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This book should help advance the cause of mycology and mushroom biology worldwide. It will be an important reference for those who are interested in research as well as in the cultivation of mushrooms. Growing Gourmet and Medicinal Mushrooms is unique not only in its treatment of the technical aspects of growing gourmet and medicinal mushrooms, but also in its emphasis on the environmental importance of mushrooms in terms of world biological diversity. —S. T. Chang, Ph.D., The Chinese University of Hong Kong Growing Gourmet and Medicinal Mushrooms is a visionary quest— and Paul Stamets is your best possible guide—not just for informing you about growing mushrooms, but for transforming you into a myco-warrior, an active participant in a heroic, Gaian process of planetary health through mushroom cultivation. —Gary Lincoff, author of The Audubon Field Guide to Mushrooms Stamets draws on the collective experience of centuries of mushroom cultivation, creating a revolutionary model for the use of higher fungi. Not only does he cover every aspect of cultivation, he also addresses the issues of environmentalism, health, and business. —Alan Bessette, Ph.D., Utica College of Syracuse University Growing Gourmet and Medicinal Mushrooms is the most comprehensive treatment of the subject I have seen in my thirty years as a mycologist and mushroom specialist. —S. C. Jong, Ph.D., The American Type Culture Collection Pick up this book and prepare to be swept away into the world of mushroom cultivation on the tide of Paul’s contagious enthusiasm. Doers and dreamers, students and teachers will all find something to enjoy in this book. —Nancy Smith Weber, Ph.D., Forest Sciences Department, Oregon State University This book, a true labor of love, makes a major contribution to our knowledge of the practical production of gourmet and medicinal mushrooms. —Dan Royse, Ph.D., Penn State College of Agricultural Sciences C opyright © 1993, 2000 by Paul Stamets All rights reserved. Published in the United States by Ten Speed P; ress, an imprint of the Crown Publishing Group, a division of Random House, Inc., New York. www.crownpublishing.com www.tenspeed.com Ten Speed Press and the Ten Speed Press colophon are registered trademarks of Random House, Inc. Photograph of Chinese rank badge (Wild Goose, 4th Rank) on this page courtesy of Beverley Jackson. Cover design by Andrew Lenzer and Jeff Brandenburg Interior design by Jeff Brandenburg Library of Congress Cataloging-in-Publication Data Stamets, Paul. Growing gourmet and medicinal mushrooms = [Shokuyo oyobi yakuyo kinoko no saibai] : a companion guide to The Mushroom Cultivator / by Paul Stamets. — 3rd ed. p. cm. Includes bibliographical references (p.). eISBN: 978-1-60774-138-1 1. Mushroom culture. I. Title: Growing gourmet and medicinal mushrooms. II. Title: Shokuyo oyobi yakuyo kinoko no saibai. SB353.S73 2000 635′.8-dc21 v3.1 00-042584 Mycotopia: An environment wherein ecological equilibrium is enhanced through the judicious use of fungi for the betterment of all lifeforms. To my family and the Warriors of Hwa Rang Do Contents Foreword Acknowledgments Introduction C HAPTER 1. Mushrooms, Civilization, and History C HAPTER 2. The Role of Mushrooms in Nature The Mycorrhizal Gourmet Mushrooms: Matsutake, Boletus, Chanterelles, and Truffles Parasitic Mushrooms: Blights of the Forest Saprophytic Mushrooms: The Decomposers The Global Environmental Shift and the Loss of Species Diversity Catastrophia: Nature as a Substrate Supplier Mushrooms and Toxic Wastes Mushroom Mycelium and Mycofiltration C HAPTER 3. Selecting a Candidate for Cultivation C HAPTER 4. Natural Culture: Creating Mycological Landscapes Methods of Mushroom Culture Spore-Mass Inoculation Transplantation: Mining Mycelium from Wild Patches Inoculating Outdoor Substrates with Pure Cultured Spawn When to Inoculate an Outdoor Mushroom Patch Site Location of a Mushroom Patch Stumps as Platforms for Growing Mushrooms Log Culture C HAPTER 5. Permaculture with a Mycological Twist: The Stametsian Model for a Synergistic Mycosphere C HAPTER 6. Materials for Formulating a Fruiting Substrate Raw Materials Suitable Wood Types: Candidate Tree Species Cereal Straws Paper Products: Newspaper, Cardboard, Books Corncobs and Cornstalks Coffee and Banana Plants Sugarcane Bagasse Seed Hulls Soybean Roughage (Okara) Supplements Structure of the Habitat C HAPTER 7. Biological Efficiency: An Expression of Yield C HAPTER 8. Homemade vs. Commercial Spawn C HAPTER 9. The Mushroom Life Cycle C HAPTER 10. The Six Vectors of Contamination C HAPTER 11. Mind and Methods for Mushroom Culture Overview of Techniques for Cultivating Mushrooms C HAPTER 12. Culturing Mushroom Mycelium on Agar Media Preparing Nutrified Agar Media Pouring Agar Media Starting a Mushroom Strain by Cloning Cloning Wild vs. Cultivated Mushrooms How to Collect Spores Germinating Spores Purifying a Culture C HAPTER 13. The Stock Culture Library: A Genetic Bank of Mushroom Strains Preserving the Culture Library The Stamets “P” Value System Iconic Types of Mushroom Mycelium The Event of Volunteer Primordia on Nutrified Agar Media C HAPTER 14. Evaluating a Mushroom Strain Features for Evaluating and Selecting a Mushroom Strain C HAPTER 15. Generating Grain Spawn Formulas for Creating Grain Spawn First-Generation Grain Spawn Masters Second-and Third-Generation Grain Spawn Autoclavable Spawn Bags Liquid-inoculation Techniques Spore-Mass Inoculation Liquid-inoculation Techniques: Mycelial Fragmentation and Fermentation Pelletized (Granular) Spawn Matching the Spawn with the Substrate: Critical Choices on the Mycelial Path Spawn Storage C HAPTER 16. Creating Sawdust Spawn C HAPTER 17. Growing Mushrooms on Enriched Sawdust The Supplemented Sawdust “Fruiting” Formula: Creating the Production Block Testing for Moisture Content Choosing a Sterilizer, aka Retort or Autoclave Sterilization of Supplemented Substrates Post-Autoclaving Unloading the Autoclave Atmospheric Steam Sterilization of Sawdust Substrates Inoculation of Supplemented Sawdust: Creating the Production Block Incubation of the Production Blocks Achieving Full Colonization on Supplemented Sawdust Handling the Blocks Post-Full Colonization C HAPTER 18. Cultivating Gourmet Mushrooms on Agricultural Waste Products Alternative Fruiting Formulas Heat-Treating the Bulk Substrate The Hot Water Bath Method: Submerged Pasteurization The “Phase II” Chamber: Steam Pasteurization Alternative Methods for Rendering Straw and Other Bulk Materials for Cultivation The Hydrated Lime Bath The Bleach Bath The Hydrogen Peroxide Technique The High-Pressure Extrusion Method The Detergent Bath Yeast Fermentation C HAPTER 19. Cropping Containers Tray Culture Vertical Wall Culture Slanted Wall or A-Frame Culture Bag Culture Column Culture Bottle Culture C HAPTER 20. Casing: A Topsoil Promoting Mushroom Formation C HAPTER 21. Growth Parameters for Gourmet and Medicinal Mushroom Species Spawn Run: Colonizing the Substrate Primordia Formation: The Initiation Strategy Fruitbody (Mushroom) Development The Gilled Mushrooms The Himematsutake Mushroom Agaricus blazei The Portobello Mushroom Agaricus brunnescens The Black Poplar Mushroom Agrocybe aegerita The Shaggy Mane Coprinus comatus The Enoki Mushroom Flammulina velutipes The Clustered Wood-lovers The Brown-Gilled Woodlover Hypholoma capnoides Kuritake (The Chestnut Mushroom) Hypholoma sublateritium The Beech Mushrooms Buna-Shimeji Hypsizygus tessulatus Shirotamogitake Hypsizygus ulmarius The Shiitake Mushroom Lentinula edodes The Nameko Mushroom Pholiota nameko The Oyster Mushrooms Golden Oyster Mushroom Pleurotus citrinopileatus The Abalone Mushroom Pleurotus cystidiosus The Pink Oyster Mushroom Pleurotus djamor The King Oyster Mushroom Pleurotus eryngii The Tarragon Oyster Mushroom Pleurotus euosmus The Tree Oyster Mushroom Pleurotus ostreatus The Phoenix or Indian Oyster Mushroom Pleurotus pulmonarius, “P. sajor-caju” The King Tuber Oyster Mushroom Pleurotus tuberregium The Caramel Capped Psilocybes Psilocybe cyanescens complex The King Stropharia Mushroom Stropharia rugosoannulata The Paddy Straw Mushroom Volvariella volvacea The Polypore Mushrooms Reishi or Ling Chi Ganoderma lucidum Maitake or Hen-of-the-Woods Grifola frondosa Zhu Ling or the Umbrella Polypore Polyporus umbellatus Turkey Tail or Yun Zhi Trametes versicolor The Lion’s Mane Hericium erinaceus The Wood Ears Auricularia polytricha The Jelly Mushrooms White Jelly Mushroom Tremella fuciformis The Cauliflower Mushrooms The Cauliflower Mushroom Sparassis crispa The Morels (Land-Fish Mushrooms) The Morel Life Cycle The Development of Indoor Morel Cultivation The Black Morels Morchella angusticeps and Allies C HAPTER 22. Maximizing the Substrate’s Potential through Species Sequencing C HAPTER 23. Harvesting, Storing, and Packaging Mushrooms for Market Harvesting the Crop Packaging and Storing the Crop for Market Drying Mushrooms Marketing the Product C HAPTER 24. Mushroom Recipes: Enjoying the Fruits of Your Labors C HAPTER 25. Cultivation Problems and Their Solutions: A Troubleshooting Guide Agar Culture Grain Culture Straw Culture Supplemented Sawdust Culture Pre-harvest Period Harvest Stage Post-harvest APPENDICES APPENDIX 1. Description of Environments for a Mushroom Farm The Laboratory Complex The Growing Room Complex APPENDIX 2. Designing and Building a Spawn Laboratory Design Criteria for a Spawn Laboratory Good Clean Room Habits: Helpful Suggestions for Minimizing Contamination in the Laboratory APPENDIX 3. The Growing Room: An Environment for Mushroom Formation and Growth Design Criteria for the Growing Rooms Managing the Growing Rooms: Good Habits for the Personnel APPENDIX 4. Resource Directory Recommended Mushroom Field Guides Mushroom Book Suppliers Annual Mushroom Festivals and Events Mushroom Cultivation Seminars and Training Centers Mushroom Study Tours and Adventures International Mushroom Associations North American Mushroom Societies and Associations Mushroom Growers Associations Sources for Mushroom Cultures Sources for Mushroom Spawn Sources for Marketing Information Mushroom Newsletters and Journals Mushroom Museums Sources for Medicinal Mushroom Products Mycological Resources on the Internet APPENDIX 5. Analyses of Basic Materials Used in Substrate Preparation APPENDIX 6. Data Conversion Tables Glossary Bibliography Photo and Illustration Credits Index Mushrooms—fleshy fungi—are the premier recyclers on the planet. Fungi are essential to recycling organic wastes and the efficient return of nutrients back into the ecosystem. Not only are they recognized for their importance within the environment, but also for their effect on human evolution and health. Yet, to date, the inherent biological power embodied within the mycelial network of mushrooms largely remains a vast, untapped resource. As we begin the twenty-first century, ecologists, foresters, bioremediators, pharmacologists, and mushroom growers are converging at a new frontier of knowledge, wherein enormous biodynamic forces are at play. Only recently have we learned enough about the cultivation of mushrooms to tap into their inherent biological power. Working with mushroom mycelium en masse will empower every country, farm, recycling center, and individual with direct economic, ecological, and medical benefits. Through the genius of evolution, the Earth has selected fungal networks as a governing force managing ecosystems. This sentient network responds quickly to catastrophia. I believe the mycelium is Earth’s natural Internet, a neural network of communicating cells. All landmasses are crisscrossed with interspersing mosaics of mycelial colonies. With more than a mile of cells in a cubic inch of soil, the fungi are moving steadily, although silently all around us. This vast mass of cells, in the hundreds of billions of tons, represents a collective intelligence, like a computer honed to improve itself. Only now are scientists discovering that it is the microbial community upon which all higher life forms are dependent. And only now do we know how to join in alliance with them to improve life. As we begin a new century, myco-technology is a perfect example of the equation of good environmentalism, good health, and good business. This book strives to create new models for the future use of higher fungi in the environment. As woodland habitats, especially old growth forests, are lost to development, mushroom diversity also declines. Wilderness habitats still offer vast genetic resources for new strains. The temperate forests of North America, particularly the mycologically rich Pacific Northwest, may well be viewed in the twenty-first century as pharmaceutical companies viewed the Amazon Basin earlier in the twentieth century. Hence, mushroom cultivators should preserve this gene pool now for its incalculable, future value. The importance of many mushroom species may not be recognized for decades to come. In many ways, this book is an offspring of the marriage of many cultures arising from the worldwide use of mushrooms as food, as religious sacraments in Mesoamerica, and as medicine in Asia. We now benefit from the collective experience of lifetimes of mushroom cultivation. As cultivators we must continue to share, explore, and expand the horizons of the human/fungal relationship. In the future, humans and mushrooms must bond in an evolutionary partnership. By empowering legions of individuals with the skills of tissue culture and mycelial management, future generations will be able to better manage our resources and improve life on this planet. Now that the medical community widely recognizes the healthstimulating properties of mushrooms, a combined market for gourmet and medicinal foods is rapidly emerging. People with compromised immune systems would be wise to create their own medicinal mushroom gardens. I envision the establishment of a community-based, resource-driven industry, utilizing recyclable materials in a fashion that strengthens ecological equilibrium and human health. As recycling centers flourish, their by-products include streams of organic waste, which cultivators can divert into mushroom production. I foresee a network of environmentally sensitive and imaginative individuals presiding over this new industry, which has previously been controlled by a few mega-businesses. The decentralization began with The Mushroom Cultivator in 1983, and continues with Growing Gourmet and Medicinal Mushrooms. Join me in the next phase of this continuing revolution. I first acknowledge the Mushrooms who have been my greatest teachers. They are the Body Intellect, the Neural Network of this book. My family has been extremely patient and forgiving during this multiyear project. Azureus and LaDena have tolerated my insistent need for their modeling talents and have helped on many mushroom projects. Dusty Wu Yao is credited for her research skills, support, humor, and love. My parents have taught me many things. My father championed education and science and impressed upon me that a laboratory is a natural asset to every home. My mother taught me patience and kindness, and that precognition is a natural part of the human experience. My brother John first piqued my interest for mushrooms upon his return from adventures in Colombia and Mexico. Additionally, his knowledge on the scientific method of photography has greatly helped improve my own techniques. In some mysterious way, their combined influences set the stage for my unfolding love of fungi. Other people warrant acknowledgement in their assistance in the completion of this book. Andrew Weil played a critical role in helping build the creative milieu, the wellspring of spiritual chi from which this manuscript flowed. Gary Lincoff was extremely helpful in uncovering some of the more obscure references and waged intellectual combat with admirable skill. Brother Bill Stamets is thanked for his critical editorial remarks. Satit Thaithatgoon, my friend from Thailand, is appreciated for his insights about mushroom culture and life. I must thank Kit and Harley Barnhart for their advice on photographic technique. Michael Beug deserves acknowledgment for his unwavering support through all these years. Erik Remmen kept me healthy and strong through the many years of rigorous training in the ancient and noble martial art of Hwarang Do. Joseph Ammirati, David Arora, Julie Bennett, Alan and Arleen Bessette, David Brigham, Janet Butz, Jonathan Caldwell, Alice Chen, Jeff Chilton, Ken Cochran, Don Coombs, Kim and Troy Donahue, Robert Ellingham, Gaston Guzman, Paxton Hoag, John Holliday, Rick Hoss, Lou Hsu, Eric Iseman, Loren Israelson, Omon Isikhuemhen, Barbara King, Mike Knoke, Alexander Krenov, Gary Leatham, Andrew Lenzer, Mike Maki, Andrew H. Miller, Orson and Hope Miller, Scott Moore, Tomiro Motohashi, Peter Mohs, Yoshikazu Murai, Takashi Mizuno, Takeshi Nakazawa, Louise North, George Osgood, Christiane Pischl, David Price, Paul Przybylowicz, Warren Rekow, Scott Redhead, Rusty Rodriguez, Maggie Rogers, Luiz Amaro Pachoa de Silva, Bulmaro Solano, Lillian Stamets, David Sumerlin, Ralph Tew, Harry Thiers, Tom O’Dell, James Trappe, Solomon Wasser, Dusty Yao, and Rytas Vilgalys all helped in their own special ways. The late Jim Roberts, of Lambert Spawn, gained my respect and admiration for his devotion to helping the gourmet mushroom industry. And, I will never forget the generosity shown to me by the late Alexander Smith and Daniel Stuntz who were instrumental in encouraging me to continue in the field of mycology—in spite of those who fervently opposed me. Companies that unselfishly contributed photographic material to this work, and to whom I am grateful, are The BOTS Group, The Minnesota Forest Resource Center, The Growing Company, DXN Company, Morel Mountain, Organotech, and Ostrom’s Mushroom Farms. I would also like to thank The Mushroom Council and the American Mushroom Institute. The Evergreen State College generously supported my studies with Psilocybe mushrooms and in scanning electron microscopy. Finally, I wish to acknowledge all those bewildered and bemushroomed researchers who have paved the way into the future. For your help on this odyssey through life, I will forever be in your debt. Mushrooms have never ceased to amaze me. The more I study them, the more I realize how little I have known, and how much more there is to learn. For thousands of years, fungi have evoked a host of responses from people—from fear and loathing to reverent adulation. And I am no exception. When I was a little boy, wild mushrooms were looked upon with foreboding. It was not as if my parents were afraid of them, but our Irish heritage lacked a tradition of teaching children anything nice about mushrooms. In this peculiar climate of ignorance, rains fell and mushrooms magically sprang forth, wilted in the sun, rotted, and vanished without a trace. Given the scare stories told about “experts” dying after eating wild mushrooms, my family gave me the best advice they could: Stay away from all mushrooms, except those bought in the store. Naturally rebellious, I took this admonition as a challenge, a call to arms, firing up an already overactive imagination in a boy hungry for excitement. When we were seven, my twin brother and I made a startling mycological discovery—Puffballs! We were told that they were not poisonous but if the spores got into our eyes, we would be instantly blinded! This information was quickly put to good use. We would viciously assault each other with mature puffballs, which would burst upon impact and emit a cloud of brown spores. The battle would continue until all the puffballs in sight had been hurled. They provided us with hours of delight over the years. Neither one of us ever went blind—although we both suffer from very poor eyesight. You must realize that to a seven-year-old these free, ready-made missiles satisfied instincts for warfare on the most primal of levels. This is my earliest memory of mushrooms, and to this day I consider it to be a positive emotional experience. (Although I admit a psychiatrist might like to explore these feelings in greater detail.) Not until I became a teenager did my hunter-gatherer instincts resurface, when a relative returned from extensive travels in South America. With a twinkle in his eyes, he spoke of his experiences with the sacred Psilocybe mushrooms. I immediately set out to find these species, not in the jungles of Colombia, but in the fields and forests of Washington State where they were rumored to grow. For the first several years, my searches provided me with an abundance of excellent edible species, but no Psilocybes. Nevertheless, I was hooked. When hiking through the mountains, I encountered so many mushrooms. Each was a mystery until I could match them with descriptions in a field guide. I soon came to learn that a mushroom was described as “edible,” “poisonous,” or my favorite, “unknown,” based on the experiences of others like me, who boldly ingested them. People are rarely neutral in their opinion about mushrooms— either they love them or they hate them. I took delight in striking fear into the hearts of the latter group, whose illogical distrust of fungi provoked my overactive imagination. When I enrolled in the Evergreen State College in 1975, my skills at mushroom identification earned the support of a professor with similar interests. My initial interest was taxonomy, and I soon focused on fungal microscopy. The scanning electron microscope revealed new worlds, dimensional landscapes I never dreamed possible. As my interest grew, the need for fresh material year-round became essential. Naturally, these needs were aptly met by learning cultivation techniques, first in petri dishes, then on grain, and eventually on a wide variety of materials. In the quest for fresh specimens, I had embarked upon an irrevocable path that would steer my life on its current odyssey. Paul Stamets in the virgin rainforest of Washington State, in route to collect new strains of wild mushrooms. Humanity’s use of mushrooms extends back to Paleolithic times. Few people—even anthropologists—comprehend how influential mushrooms have been in affecting the course of human evolution. They have played pivotal roles in ancient Greece, India, and Mesoamerica. True to their beguiling nature, fungi have always elicited deep emotional responses: from adulation by those who understand them to outright fear by those who do not. The historical record reveals that mushrooms have been used for less than benign purposes. Claudius II and Pope Clement VII were both killed by enemies who poisoned them with deadly Amanitas. Buddha died, according to legend, from a mushroom that grew underground. Buddha was given the mushroom by a peasant who believed it to be a delicacy. In ancient verse, that mushroom was linked to the phrase “pig’s foot” but has never been identified. (Although Truffles grow underground, and pigs are used to find them, no deadly poisonous species are known.) The oldest archaeological record of probable mushroom use is a Tassili image from a cave dating back 5000 years B.C. (Lhote, 1987). The artist’s intent is clear. Mushrooms with electrified auras are depicted outlining a bee-masked dancing shaman. The spiritual interpretation of this image transcends time and is obvious. No wonder the word “bemushroomed” has evolved to reflect the devout mushroom lover’s state of mind. In the fall of 1991, hikers in the Italian Alps came across the wellpreserved remains of a man who died over 5,300 years ago, approximately 1,700 years later than the Tassili cave artist. Dubbed the “Iceman” or “Oetzi” by the news media, he was well-equipped with a knapsack, flint axe, a string of dried Birch Polypores (Piptoporus betulinus), a tinder fungus (Fomes fomentarius), and another as-yet-unidentified mushroom that may have had magicospiritual significance (Peintner et al. 1998). Polypores can be used as spunk for starting fires and medicine for treating wounds. Further, a rich tea with immuno-enhancing and antibacterial properties can be prepared by boiling these mushrooms. Equipped for traversing the high alpine wilderness, this intrepid adventurer had discovered the value of the noble polypores. Even today, this knowledge can be life-saving for anyone astray in the wilderness. 2000+ year-old Mesoamerican mushroom stone. Fear of mushroom poisoning pervades every culture, sometimes reaching phobic extremes. The term mycophobic describes those individuals and cultures who look upon fungi with fear and loathing. The English and Irish epitomize mycophobic cultures. In contrast, mycophilic societies can be found throughout Asia and Eastern Europe, especially among Polish, Russian, and Italian peoples. These societies have enjoyed a long history of mushroom use, with as many as a hundred common names to describe the mushroom varieties they love. An investment banker named R. Gordon Wasson intensively studied the use of mushrooms by diverse cultures. His studies concentrated on the use of mushrooms by Mesoamerican, Russian, English, and Indian cultures. With the French mycologist Dr. Roger Heim, Wasson published research on Psilocybe mushrooms in Mesoamerica, and on Amanita mushrooms in Eurasia/Siberia. Wasson’s studies spanned a lifetime marked by a passionate love for fungi. His publications include Mushrooms, Russia, and History; The Wondrous Mushroom: Mycolatry in Mesoamerica; Maria Sabina and Her Mazatec Mushroom Velada; and Persephone’s Quest: Entheogens and the Origins of Religion. More than any individual of the twentieth century, Wasson kindled interest in ethnomycology to its present state of intense study. Wasson died on Christmas Day in 1986. One of Wasson’s most provocative findings can be found in Soma: Divine Mushroom of Immortality (1976) where he postulated that the mysterious Soma in Vedic literature, a red fruit leading to spontaneous enlightenment for those who ingested it, was actually a mushroom. The Vedic symbolism carefully disguised its true identity: Amanita muscaria, the hallucinogenic Fly Agaric. Many cultures portray Amanita muscaria as the archetypal mushroom, invoking both fear and admiration. Although some Vedic scholars disagree with his interpretation, Wasson’s exhaustive research still stands (Brough, 1971 and Wasson, 1972). Meso-American mushroom stones, circa 300 B.C., from the Pacific slope of Guatemala. Aristotle, Plato, Homer, and Sophocles all participated in religious ceremonies at Eleusis where an unusual temple honored Demeter, the Goddess of Earth. For over two millennia, thousands of pilgrims journeyed fourteen miles from Athens to Eleusis, paying the equivalent of a month’s wage for the privilege of attending the annual ceremony. The pilgrims were ritually harassed on their journey to the temple, apparently in good humor. Upon arriving at the temple, they gathered in the initiation hall, a great telestrion. Inside the temple, pilgrims sat in rows that descended step-wise to a hidden, central chamber from which a fungal concoction was served. An odd feature was an array of columns, beyond any apparent structural need, whose designed purpose escapes archaeologists. The pilgrims spent the night together and reportedly came away forever changed. In this pavilion crowded with pillars, ceremonies occurred, known by historians as the Eleusinian Mysteries. No revelation of the ceremony’s secrets could be mentioned under the punishment of imprisonment or death. These ceremonies continued until repressed in the early centuries of the Christian era. In 1977, at a mushroom conference on the Olympic Peninsula, R. Gordon Wasson, Albert Hofmann, and Carl Ruck first postulated that the Eleusinian Mysteries centered on the use of psychoactive fungi. Their papers were later published in a book entitled The Road to Eleusis: Unveiling the Secret of the Mysteries (1978). That Aristotle and other founders of Western philosophy undertook such intellectual adventures, and that this secret ceremony persisted for nearly 2,000 years, underscores the profound impact that fungal rites have had on the evolution of Western consciousness. Pre-classic Mayan mushroom stone from Kaminaljuyu Highlands of Guatemala, circa 500 B.C. Mushrooms can be classified into three basic ecological groups: mycorrhizal, parasitic, and saprophytic. Although this book centers on the cultivation of the gourmet and medicinal saprophytic species, other mushrooms are also discussed. The Mycorrhizal Gourmet Mushrooms: Matsutake, Boletus, Chanterelles, and Truffles Mycorrhizal mushrooms form a mutually dependent, beneficial relationship with the roots of host plants, ranging from trees to grasses. “Myco” means mushrooms, while “rhizal” means roots. The collection of filament of cells that grow into the mushroom body is called the mycelium. The mycelia of these mycorrhizal mushrooms can form an exterior sheath covering the roots of plants and are called ectomycorrhizal. When they invade the interior root cells of host plants they are called endomycorrhizal. In either case, both organisms benefit from this association. Plant growth is accelerated. The resident mushroom mycelium increases the plant’s absorption of nutrients, nitrogenous compounds, and essential elements (phosphorus, copper, and zinc). By growing beyond the immediate root zone, the mycelium channels and concentrates nutrients from afar. Plants with mycorrhizal fungal partners can also resist diseases far better than those without. Most ecologists now recognize that a forest’s health is directly related to the presence, abundance, and variety of mycorrhizal associations. The mycelial component of topsoil within a typical Douglas fir forest in the Pacific Northwest approaches 10% of the total biomass. Even this estimate may be low, not taking into account the mass of the endomycorrhizae and the many yeast-like fungi that thrive in the topsoil. The nuances of climate, soil chemistry, and predominant microflora play determinate roles in the cultivation of mycorrhizal mushrooms in natural settings. Species native to a region are likely to adapt much more readily to designed habitats than exotic species. I am much more inclined to spend time attempting the cultivation of native mycorrhizal species than to import exotic candidates from afar. Here is a relevant example. A Truffle market in France. Truffle orchards are well established in France, Spain, and Italy, with the renowned Perigold Black Truffle, Tuber melanosporum, fetching up to $500 per pound. Only in the past thirty years has tissue culture of Truffle mycelia become widely practiced, allowing the development of planted Truffle orchards. Landowners seeking an economic return without resorting to cutting trees are naturally attracted to this prospective investment. The idea is enticing. Think of having an orchard of oaks or filberts, yielding pounds of Truffles per year for decades at several hundred dollars a pound! Several companies in this country have, in the past twenty years, marketed Truffle-inoculated trees for commercial use. Calcareous soils (i.e., high in calcium) in Texas, Washington, and Oregon have been suggested as ideal sites. Tens of thousands of dollars have been exhausted in this endeavor. Only two would-be Truffle orchards have had any success thus far, with only a small percentage of trees producing. This discouraging state of affairs should be fair warning to investors seeking profitable enterprises in the arena of Truffle cultivation. Suffice it to say that the only ones to have made money in the Truffle tree industry are those who have resold “inoculated” seedlings to other would-be trufflateurs. A group of Oregon trufflateurs has been growing the Oregon White Truffle, Tuber gibbosum. Douglas fir seedlings are inoculated with mycelium from this native species and planted in plots similar to Christmas tree farms. Several years pass before the first harvests begin. However, since Oregon White Truffles were naturally occurring nearby, whether or not the inoculation process caused the truffles to form is unclear. In Sweden, Eric Danell (1994; 1997), who is the first to grow Chantarelles (Cantharellus cibarius) with a potted pine tree in a greenhouse, is continuing an ambitious project of cultivating mycorrhizal mushrooms using a community of microorganisms as allies. (See photo here.) At the Invermay Agricultural Center in New Zealand, scientists have succeeded in inoculating pines with Matsutake (Tricholoma magnivelare) mycelia in the hope that mushrooms will appear a decade later. In New Zealand, mycorrhizal inoculations are more successful because of the extremely limited number of natural mycorrhizal candidates, in contrast to the hundreds seen in the forestlands of North America. These pilot projects hold great promise for replenishing the fungal genome of threatened mycorrhizal mushrooms in endangered ecosystems. Mycorrhizal mushrooms in Europe have suffered a radical decline in years of late. The combined effects of acid rain and other industrial pollutants, even the disaster at Chernobyl, have been suggested to explain the sudden decline of both the quantity and diversity of wild mycorrhizal mushrooms. Most mycologists believe the sudden availability of deadwood is responsible for the comparative increase in the numbers of saprophytic mushrooms. The decline in Europe portends, in a worst case scenario, a total ecological collapse of the mycorrhizal community, followed by a widespread die-back of the forests. In the past ten years, the diversity of mycorrhizal mushrooms in Europe has fallen by more than 50%! Some species, such as the Chanterelle, have all but disappeared from regions in the Netherlands where it was abundant only twenty years ago (see Arnolds, 1992; Leck, 1991; Lizon 1993, 1995). Many biologists view these mushrooms as indicator species, the first domino to fall in a series leading to the failure of the forest’s life-support systems. One method for inoculating mycorrhizae calls for the planting of young seedlings near the root zones of proven Truffle trees. The new seedlings acclimate and become “infected” with the mycorrhizae of a neighboring, parent tree. In this fashion, a second generation of trees carrying the mycorrhizal fungus is generated. After a few years, the new trees are dug up and replanted into new environments. This method has had the longest tradition of success in Europe. Scanning electron micrograph of an emerging root tip being mycorrhized by mushroom mycelia. Scanning electron micrograph of mycelia encasing the root of a tree, known as ectomycorrhizae. Another approach, modestly successful, is to dip exposed roots of seedlings into water enriched with the spore-mass of a mycorrhizal candidate. First, mushrooms are gathered from the wild and soaked in water. Thousands of spores are washed off the gills, resulting in an enriched broth of inoculum. A spore-mass slurry coming from several mature mushrooms and diluted into a 5-gallon bucket can inoculate a hundred or more seedlings. The concept is wonderfully simple. Unfortunately, success is not guaranteed. Broadcasting spore-mass onto the root zones of likely candidates is another venue that costs little in time and effort. Habitats should be selected on the basis of their parallels in nature. For instance, Chanterelles can be found in oak forests of the Midwest and in Douglas fir forests of the West. Casting spore-mass of Chanterelles into forests similar to those where Chanterelles proliferate is obviously the best choice. Although the success rate is not high, the rewards are well worth the minimum effort involved. Bear in mind that tree roots confirmed to be mycorrhized with a gourmet mushroom will not necessarily result in harvestable mushrooms. Fungi and their host trees may have long associations without the appearance of edible fruitbodies. (For more information, consult Fox, 1983.) On sterilized media, most mycorrhizal mushrooms grow slowly, compared to the saprophytic mushrooms. Their long evolved dependence on root by-products and complex soils makes media preparation inherently more complicated. Some mycorrhizal species, like Pisolithus tinctorius, a puffball favoring pines, grow quite readily on sterilized media. A major industry has evolved providing foresters with seedlings inoculated with this fungus. Mycorrhized seedlings are healthier and grow faster than non-mycorrhized ones. Unfortunately, the gourmet mycorrhizal mushroom species do not fall into the readily cultured species category. The famous Matsutake may take weeks before its mycelium fully colonizes the media on a single petri dish! Unfortunately, this rate of growth is the rule rather than the exception with the majority of gourmet mycorrhizal species. The first authenticated success in the cultivation of the Chantarelle: Pinus sylvestris in companionship with Cantharellus cibarius. Chanterelles are one of the most popularly collected wild mushrooms. In the Pacific Northwest of North America the harvesting of Chanterelles has become a controversial, multi-million dollar business. Like Matsutake, Chanterelles also form mycorrhizal associations with trees. Additionally, they demonstrate a unique interdependence on soil yeasts and pseudomonads. This type of mycorrhizal relationship makes tissue culture most difficult. At least three organisms must be cultured simultaneously: the host tree, the mushroom, and soil microflora. A red soil yeast, Rhodotorula glutinis, is crucial in stimulating spore germination. The Chanterelle life cycle may have more dimensions of biological complexity. Cultivators have yet to grow Chanterelles to the fruitbody stage under laboratory conditions. Not only do other microorganisms play essential roles, the timing of their introduction appears critical to success in the mycorrhizal theater. Senescence occurs with both saprophytic and mycorrhizal mushroom species. Often the first sign of senescence is not the inability of mycelia to grow vegetatively, but the loss of the formation of the sexually reproducing organ: the mushroom. Furthermore, the slowness from sowing the mycelium to the final stages of harvest confounds the quick feedback all cultivators need to refine their techniques. Thus, experiments trying to model how Matsutakes grow may take twenty to forty years each, the age the trees must be to support healthy, fruiting colonies of these prized fungi. Faster methods are clearly desirable, but presently only the natural model has shown any clue to success. Given the huge hurdle of time for honing laboratory techniques, I favor the “low-tech” approach of planting trees adjacent to known producers of Chanterelles, Matsutake, Truffles, and Boletus. After several years, the trees can be uprooted, inspected for mycorrhizae, and replanted in new environments. The value of the contributing forest can then be viewed, not in terms of board feet of lumber, but in terms of its ability for creating satellite, mushroom/tree colonies. When industrial or suburban development threatens entire forests, and is unavoidable, future-oriented foresters may consider the removal of the mycorrhizae as a last-ditch effort to salvage as many mycological communities as possible by simple transplantation techniques, although on a much grander scale. Until laboratory techniques evolve to establish a proven track record of successful marriages that result in harvestable crops, I hesitate to recommend mycorrhizal mushroom cultivation as an economic endeavor. Mycorrhizal cultivation pales in comparison to the predictability of growing saprophytic mushrooms like Oyster and Shiitake mushrooms. The industry simply needs the benefit of many more years of mycological research to better decipher the complex models of mycorrhizal mushroom cultivation. Oyster and Honey mushrooms sharing a stump. Parasitic Mushrooms: Blights of the Forest? Parasitic fungi are the bane of foresters. They do immeasurable damage to the health of resident tree species, but in the process create new habitats for many other organisms. Although the ecological damage caused by parasitic fungi is well understood, we are only just learning of their importance in the forest ecosystem. Comparatively few mushrooms are true parasites. Parasites live off a host plant, endangering the host’s health as it grows. Of all the parasitic mushrooms that are edible, the Honey mushroom, Armillaria mellea, is the best known. One of these Honey mushrooms, known as Armillaria gallica, made national headlines when scientists reported finding in Michigan a single colony covering 37 acres, weighing at least 220,000 pounds, with an estimated age of 1,500 years! Washington State soon responded with reports of a colony of Armillaria ostoyae covering 2,200 acres and at least 2,400 years old. With the exception of the trembling Aspen forests of Colorado, this fungus is the largest known living organism on the planet. And, it is a marauding parasite! On a well-traveled trail in the Snoqualmie Forest of Washington State, hikers have been stepping upon the largest and perhaps oldest polypore: Bridgeoporus (Oxyporus) nobilissimus, a conk that grows up to several feet in diameter and can weigh hundreds of pounds!1 This “parasitic” species grows primarily on old-growth Abies procera (California red fir) or on their stumps. Less than a dozen specimens have ever been collected. This mushroom is the first ever to be listed on any list, private or public, as an endangered species. Known only from the old-growth forests of the Pacific Northwest, the Noble Polypore’s ability to produce a conk that lives for hundreds of years distinguishes it from any other mushroom known to North America. This fact—that it produces a fruiting body that survives for centuries —suggests that the Noble Polypore has unique anti-rotting properties, antibiotics, or other compounds that could be useful medicinally. Located at the Kew Gardens in Scotland, another ancient polypore, Rigidioporus ulmarius, might also be medically significant, holding the Guinness Book of Records for the largest mushroom in the world—with an estimated weight of more than 625 pounds (284 kilograms). These examples from the fungal kingdom attract my attention in the search for candidates having potentially new medicines. With the loss of old-growth forests, cultivator– mycologists can play an all-important role in saving the fungal genome, especially in old-growth forests, a potential treasure trove of new medicines. Intrepid amateur mycologist Richard Gaines points to parasitic fungus attacking a yew tree. In the past, a parasitic fungus has been looked upon as biologically evil. This view is rapidly changing as science progresses. Montana State University researchers have discovered a new parasitic fungus attacking the yew tree. This new species is called Taxomyces andreanae and is medically significant for one notable feature: it produces minute quantities of the potent anticarcinogen Taxol, a proven treatment for breast cancer (Stone, 1993). This new fungus was studied and now a synthetic form of this potent drug is available for cancer patients. Recently, a leaf fungus isolated in the Congo has been discovered that duplicates the effect of insulin, but is orally active. Even well known medicines from fungi harbor surprises. A mycologist at Cornell University (Hodge et al. 1996) recently discovered that the fungus responsible for the multibillion dollar drug, cyclosporin, has a sexual stage in Cordyceps subsessilis, a parasitic mushroom attacking scarab beetle larvae. Of the estimated 1,500,000 species of fungi, approximately 70,000 have been identified (Hawksworth et al. 1995), and about 10,000 are mushrooms. We are just beginning to discover the importance of species hidden within this barely explored genome. Many saprophytic fungi can be weakly parasitic in their behavior, especially if a host tree is dying from other causes. These can be called facultative parasites: saprophytic fungi activated by favorable conditions to behave parasitically. Some parasitic fungi continue to grow long after their host has died. Oyster mushrooms (Pleurotus ostreatus) are classic saprophytes, although they are frequently found on dying cottonwood, oak, poplar, birch, maple, and alder trees. These appear to be operating parasitically when they are only exploiting a rapidly evolving ecological niche. Most of the parasitic fungi are microfungi and are barely visible to the naked eye. In mass, they cause the formation of cankers and shoot blights. Often their preeminence in a middle-aged forest is symptomatic of other imbalances within the ecosystem. Acid rain, groundwater pollution, insect damage, and loss of protective habitat all are contributing factors unleashing parasitic fungi. After a tree dies, from parasitic fungi or other causes, saprophytic fungi come into play. The cultivation of the Button mushroom in caves near Paris in 1868. Note candle used for illumination. (Robinson, 1885) Saprophytic Mushrooms: The Decomposers Most of the gourmet mushrooms are saprophytic, wood-decomposing fungi. Saprophytic fungi are the premier recyclers on the planet. The filamentous mycelial network is designed to weave between and through the cell walls of plants. The enzymes and acids they secrete degrade large molecular complexes into simpler compounds. All ecosystems depend upon fungi’s ability to decompose organic plant matter soon after it is rendered available. The end result of their activity is the return of carbon, hydrogen, nitrogen, and minerals back into the ecosystem in forms usable to plants, insects, and other organisms. As decomposers, they can be separated into three key groups. Some mushroom species cross over from one category to another depending upon prevailing conditions. Primary Decomposers: These are the fungi first to capture a twig, a blade of grass, a chip of wood, a log or stump. Primary decomposers are typically fast-growing, sending out ropy strands of mycelium that quickly attach to and decompose plant tissue. Most of the decomposers degrade wood. Hence, the majority of these saprophytes are woodland species, such as Oyster mushrooms (Pleurotus species), Shiitake (Lentinula edodes), and King Stropharia (Stropharia rugosoannulata). However, each species has developed specific sets of enzymes to break down lignin-cellulose, the structural components of most plant cells. Once the enzymes of one mushroom species have broken down the lignin-cellulose to its fullest potential, other saprophytes utilizing their own repertoire of enzymes can reduce this material even further. Secondary Decomposers: These mushrooms rely on the previous activity of other fungi to partially break down a substrate to a state wherein they can thrive. Secondary decomposers typically grow from composted material. The actions of other fungi, actinomycetes, bacteria, and yeasts all operate within compost. As plant residue is degraded by these microorganisms, the mass, structure, and composition of the compost is reduced, and proportionately available nitrogen is increased. Heat, carbon dioxide, ammonia, and other gases are emitted as by-products of the composting process. Once these microorganisms (especially actinomycetes) have completed their life cycles, the compost is susceptible to invasion by a select secondary decomposer. A classic example of a secondary decomposer is the Button Mushroom, Agaricus brunnescens, the most commonly cultivated mushroom. Another example is Stropharia ambigua, which invades outdoor mushroom beds after wood chips have been first decomposed by a primary saprophyte. Tertiary Decomposers: An amorphous group, the fungi represented by this group are typically soil dwellers. They survive in habitats that are years in the making from the activity of the primary and secondary decomposers. Fungi existing in these reduced substrates are remarkable in that the habitat appears inhospitable for most other mushrooms. A classic example of a tertiary decomposer is Aleuria aurantia, the Orange Peel Mushroom. This complex group of fungi often poses unique problems to would-be cultivators. Panaeolus subbalteatus is yet another example. Although one can grow it on composted substrates, this mushroom has the reputation of growing prolifically in the discarded compost from Button mushroom farms. Other tertiary decomposers include species of Conocybe, Agrocybe, Pluteus, and some Agaricus species. The floor of a forest is constantly being replenished by new organic matter. Primary, secondary, and tertiary decomposers can all occupy the same location. In the complex environment of the forest floor, a “habitat” can actually be described as the overlaying of several, mixed into one. And, over time, as each habitat is being transformed, successions of mushrooms occur. This model becomes infinitely complex when taking into account the interrelationships of not only the fungi to one another, but also the fungi to other microorganisms (yeasts, bacteria, protozoa), plants, insects, and mammals. Primary and secondary decomposers afford the most opportunities for cultivation. To select the best species for cultivation, several variables must be carefully matched. Climate, available raw materials, and the mushroom strains all must interplay for cultivation to result in success. Native species are the best choices when you are designing outdoor mushroom landscapes. Temperature-tolerant varieties of mushrooms are more forgiving and easier to grow than those that thrive within finite temperature limits. In warmer climates, moisture is typically more rapidly lost, narrowing the opportunity for mushroom growth. Obviously, growing mushrooms outdoors in a desert climate is more difficult than growing mushrooms in moist environments where they naturally abound. Clearly, the site selection of the mushroom habitat is crucial. The more exposed a habitat is to direct midday sun, the more difficult it is for mushrooms to flourish. Many mushrooms actually benefit from indirect sunlight, especially in the northern latitudes. Pacific Northwest mushroom hunters have long noted that mushrooms grow most prolifically, not in the darkest depths of a woodlands, but in environments where shade and “dappled” sunlight are combined. Sensitivity-to-light studies have established that various species differ in their optimal response to wavebands of sunlight. Nevertheless, few mushrooms enjoy prolonged exposure to direct sunlight. The Global Environmental Shift and the Loss of Species Diversity Studies in Europe show a frightening loss of species diversity in forestlands, most evident with the mycorrhizal species. Many mycologists fear many mushroom varieties, and even species, will soon become extinct. As the mycorrhizal species decline in both numbers and variety, the populations of saprophytic and parasitic fungi initially rise as a direct result of the increased availability of deadwood debris. However, as woodlots are burned and replanted, the complex mosaic of the natural forest is replaced by a highly uniform, mono-species landscape. Because the replanted trees are nearly identical in age, the cycle of debris replenishing the forest floor is interrupted. This new “ecosystem” cannot support the myriad fungi, insects, small mammals, birds, mosses, and flora so characteristic of ancestral forests. In pursuit of commercial forests, the native ecology has been supplanted by a biologically anemic woodlot. This woodlot landscape is barren in terms of species diversity. With the loss of every ecological niche, the sphere of biodiversity shrinks. At some presently unknown level, the diversity will fall below the critical mass needed for sustaining a healthy forestland. Once passed, the forest may not ever recover without direct and drastic counteraction: the insertion of multiage trees of different species, with varying canopies and undergrowth. Even with such extraordinary action, the complexity of a replanted forest cannot match that which has evolved for thousands of years. Little is understood about prerequisite microflora—yeasts, bacteria, and micro-fungi—upon which the ancient forests are dependent. As the number of species declines, whole communities of organisms disappear. New associations are likewise limited. If this trend continues, I believe the future of new forests, indeed the planet, is threatened. Apart from the impact of wood harvest, the health of biologically diverse forests is in increasing jeopardy due to acid rain and other airborne toxins. Eventually, the populations of all fungi— saprophytic and mycorrhizal—suffer as the critical mass of dead trees declines more rapidly than it is replenished. North Americans have already experienced the results of habitat loss from the European forests. Importation of wild picked mushrooms from Mexico, the United States, and Canada to Europe has escalated radically in the past twenty years. This increase in demand is not due just to the growing popularity of eating wild mushrooms. It is a direct reflection of the decreased availability of wild mushrooms from regions of the world suffering from ecological shock. The woodlands of North America are only a few decades behind the forests of Europe and Asia. With the loss of habitat of the mycorrhizal gourmet mushrooms, market demands for gourmet mushrooms should shift to those that can be cultivated. Thus, the pressure on this not-yet-renewable resource would be alleviated. I believe the judicious use of saprophytic fungi by homeowners as well as foresters may well prevent widespread parasitic disease vectors. Selecting and controlling the types of saprophytic fungi occupying these ecological niches can benefit both forester and forestland. Catastrophia: Nature as a Substrate Supplier Many saprophytic fungi benefit from catastrophic events in the forests. When hurricane-force winds rage across woodlands, enormous masses of dead debris are generated. The older trees are especially prone to fall. Once the higher canopy is gone, the growth of a younger, lower canopy of trees is triggered by the suddenly available sunlight. The continued survival of young trees is dependent upon the quick recycling of nutrients by the saprophytic fungi in decomposing deadwood. Every time catastrophes occur—hurricanes, tornadoes, volcanoes, floods, and even earthquakes—the resulting deadwood becomes a stream of inexpensive substrate materials. In a sense, the cost of mushroom production is underwritten by natural disasters. Unfortunately, to date, few individuals and communities take advantage of catastrophia as a fortuitous event for enhancing mycelial growth. However, once the economic value of recycling with gourmet and medicinal mushrooms is clearly understood, and with the increasing popularity of backyard cultivation, catastrophia can be viewed as a positive event, at least in terms of providing new economic opportunities and positive environmental consequences for those who are mycologically astute. Mushrooms and Toxic Wastes In heavily industrialized areas, the soils are typically contaminated with a wide variety of pollutants, particularly petroleum-based compounds, polychlorinated biphenols (PCBs), heavy metals, pesticide-related compounds, and even radioactive wastes. Mushrooms grown in polluted environments can absorb toxins directly into their tissues, especially heavy metals (Bressa, 1988; Stijve 1974, 1976, 1992). As a result, mushrooms grown in these environments should not be eaten. Recently, a visitor to Ternobyl, a city about 60 miles from Chernobyl, the site of the world’s worst nuclear power plant accident, returned to the United States with a jar of pickled mushrooms. The mushrooms were radioactive enough to set off Geiger counter alarms as the baggage was being processed. Customs officials promptly confiscated the mushrooms. Unfortunately, most toxins are not so readily detected. A number of fungi can, however, be used to detoxify contaminated environments, in a process called “bioremediation.” The white rot fungi (particularly Phanerochaete chrysosporium) and brown rot fungi (notably Gloephyllum species) are the most widely used. Most of these wood-rotters produce lignin peroxidases and cellulases, which have unusually powerful degradative properties. These extracellular enzymes have evolved to break down plant fiber, primarily lignincellulose, the structural component in woody plants, into simpler forms. By happenstance, these same enzymes also reduce recalcitrant hydrocarbons and other manufactured toxins. Given the number of industrial pollutants that are hydrocarbon-based, fungi are excellent candidates for toxic waste cleanup and are viewed by scientists and government agencies with increasing interest. Current and prospective future uses include the detoxification of PCB (polychloralbiphenols), PCP (pentachlorophenol), oil, and pesticide/herbicide residues. They are even being explored for ameliorating the impact of radioactive wastes by sequestering heavy metals. A far-reaching patent has been applied for using mycelial mats to break down toxic wastes, particularly those that are hydrocarbon based, including most petroleum products, pesticides, PCBs (polychlorobiphenols), and PCPs (pentachlorophenols), and for eliminating the flow of pathogenic bacteria into sensitive watersheds. This revolutionary patent also describes methods for effectively destroying nerve gas surrogates, including Sarin and VX, as well as chemical and biological warfare components by training the mushroom mycelium (Venter, A. J., 1999; Word et al. 1997; Thomas et al. 1998). Bioremediation of toxic waste sites is especially attractive because the environment is treated in situ. The contaminated soils do not have to be hauled away, eliminating the extraordinary expense of handling, transportation, and storage. Since these fungi have the ability to reduce complex hydrocarbons into elemental compounds, these compounds pose no threat to the environment. Indeed, these former pollutants could even be considered “fertilizer,” helping rather than harming the nutritional base of soils. Dozens of bioremediation companies have formed to solve the problem of toxic waste. Most of these companies look to the imperfect fungi. The higher fungi should not be disqualified for bioremediation just because they produce an edible fruitbody. Indeed, this group may hold answers to many of the toxic waste problems. The most vigorous rotters described in this book are the Ganoderma and Pleurotus mushrooms. Mushrooms grown from toxic wastes are best not eaten, as residual heavy metal toxins may be concentrated within the mushrooms. However, one experiment using Oyster mushrooms to degrade petroleum residues on an oil-saturated Department of Transportation lot near Bellingham, Washington, not only largely decomposed the oil, but the mushrooms were free of petroleum residues when analyzed (Stamets, 1999). Scanning electron micrograph of the mycelial network. Mushroom Mycelium and Mycofiltration The mycelium is a fabric of interconnected, interwoven strands of cells. One colony can range in size from a half-dollar to many acres. A cubic inch of soil can host up to a mile of mycelium. This organism can be physically separated, and yet behave as one. The exquisite lattice-like structure of the mushroom mycelium, often referred to as the mycelial network, is perfectly designed as a filtration membrane. Each colony extends long, complex chains of cells that fork repeatedly in matrix-like fashion, spreading to geographically defined borders. The mushroom mycelium, being a voracious forager for carbon and nitrogen, secretes extracellular enzymes that unlock organic complexes. The newly freed nutrients are then selectively absorbed directly through the cell walls into the mycelial network. In the rainy season, water carries nutritional particles through this filtration membrane, including bacteria, which often become a food source for the mushroom mycelium. The resulting downstream effluent is cleansed of not only carbon/nitrogen-rich compounds but also bacteria, in some cases nematodes, and legions of other microorganisms. The voracious Oyster mushrooms been found to be parasitic against nematodes (Thorn and Barron, 1984; Hibbett and Thorn, 1994). Extracellular enzymes act like an anesthetic and stun the nematodes, thus allowing the invasion of the mycelium directly into their immobilized bodies. The use of mycelium as a mycofilter is currently being studied by this author in the removal of biological contaminants from surface water passing directly into sensitive watersheds. By placing sawdust implanted with mushroom mycelium in drainage basins downstream from farms raising livestock, the mycelium acts as a sieve, which traps fecal bacteria and ameliorates the impact of a farm’s nitrogenrich outflow into aquatic ecosystems. This concept is incorporated into an integrated farm model and explored in greater detail in Chapter 5: Permaculture with a Mycological Twist. Oyster mushrooms fruiting on diesel-contaminated soil at a test bioremediation site near Bellingham, Washington, effectively “de-contaminating” the soil to a level where it could be used for highway landscaping. 1. Oxyporus nobilissimus has been placed in its own genus, Bridgeoporus (Burdsall et al. 1996). Many mushroom hunters would love to have their favorite edible mushroom growing in their backyard. Who would not want a patch of Matsutake, Shaggy Manes, Giant Puffballs, or the stately Prince gracing their property? As the different seasons roll along, gourmet mushrooms would arise in concert. Practically speaking, however, our knowledge of mushroom cultivation is currently limited to 100 species of the 10,000 thought to exist throughout the world. Through this book and the works of others, the number of cultivatible species will enlarge, especially if amateurs are encouraged to boldly experiment. Techniques for cultivating one species may be applied for cultivating another, often by substituting an ingredient, changing a formula, or altering the fruiting environment. Ironically, with species never before grown, the strategy of “benign neglect” more often leads to success than active interference with the natural progression of events. I have been particularly adept at this nonstrategy. Many of my early mushroom projects only produced when I left them alone. A list of candidates, which can be grown using current methods, follows. Currently we do not know how to grow those species marked by an asterisk (*). However, I believe techniques for their cultivation will soon be perfected, given a little experimentation. This list is by no means exhaustive, and will be much amended in the future. Many of these mushrooms are described as good edibles in the field guides, as listed in the Resource Directory in this book. (See Appendix 4.) Woodland Mushrooms The Wood Ears Auricularia auricula Auricularia polytricha The Prince Agaricus augustus The Almond Agaricus Agaricus subrufescens The Sylvan Agaricus Agaricus sylvicola Agaricus lilaceps* Black Poplar Agrocybe Agrocybe aegerita The Clustered Woodlovers Hypholoma capnoides Hypholoma sublateritium Psilocybe cyanescens and allies Oyster-like Mushrooms Hypsizygus ulmarius Hypsizygus tessulatus (= H. marmoreus) Pleurotus citrinopileatus (= P. cornucopiae var. citrinopileatus) Pleurotus cornucopiae Pleurotus cystidiosus (= P. abalonus, P. smithii (?)) Pleurotus djamor (=P. flabellatus, P. salmoneo-stramineus) Pleurotus dryinus* Pleurotus eryngii Pleurotus euosmus Pleurotus ostreatus Pleurotus pulmonarius (= “sajor-caju”) Tricholoma giganteum The Deer Mushroom Pluteus cervinus Shiitake Mushroom Lentinula edodes Lentinula spp. Garden Giant or King Stropharia Stropharia rugosoannulata Most polypore mushrooms Grassland Mushrooms Meadow Mushrooms Agaricus arvensis Agaricus blazei Agaricus campestris Lepiota procera Horse Mushroom Agaricus arvensis The Giant Puffball Calvatia gigantea and allies* Smooth Lepiota Lepiota naucina* The Parasol Mushroom Lepiota procera Fairy Ring Mushroom Marasmius oreades Dung Inhabiting Mushrooms The Button Mushrooms Agaricus brunnescens Agaricus bitorquis (= rodmanii) The Magic Mushrooms Psilocybe cubensis Panaeolus cyanescens (= Copelandia cyanescens) Panaeolus subbalteatus Panaeolus tropicalis (Copelandia tropicalis) Compost/Litter/Disturbed Habitat Mushrooms Shaggy Manes Coprinus comatus Scaly Lepiota Lepiota rachodes* The Termite Mushrooms Termitomyces spp.* The Blewit Lepista nuda Termitomyces robustus is one of the best of the edible mushrooms but defies human attempts at cultivation. So far only ants know the secret to growing this delicacy. Gardening with gourmet and medicinal mushrooms. Natural culture is the cultivation of mushrooms outdoors. After mycological landscapes are constructed and inoculated, the forces of nature take control. For these mycological landscapes to be sustainable, a continual flow of organic debris is essential. Although the cultivator may choose to install desired species, respect towards nature’s selection of preferred mushrooms is the only path to successful cultivation. Wild species in the landscape are natural allies. The responsibility of the cultivator is to design a habitat incorporating both wild and cultivated mushrooms, and seeking the right fits. Yet, the complex nature of creating species mosaics is still being understood. Only through the cumulative experiences of mycological landscapers can the knowledge base of this new model expand. I also call this laissez-faire cultivation. After the mushroom patch has been inoculated, it is left alone, subject to the whims of nature, except for some timely watering. The mushroom habitat is specifically designed, paying particular attention to site location, topography, sun exposure, and the use of native woods and/or garden by-products. Once prepared, the cultivator launches the selected mushroom species into a constructed habitat by spawning. In general, native mushroom species do better than exotic ones. However, even those obstacles to growing exotic species are easily overcome with some forethought to design, and the helpful suggestions of an experienced cultivator. Every day, gardeners, landscapers, rhododendron growers, arborists, and nurseries utilize the very components needed for growing mushrooms. Every pile of debris, whether it is tree trimmings, sawdust, wood chips, or a mixture of these materials, will support mushrooms. Unless selectively inoculated, debris piles become habitats of miscellaneous “weed” mushrooms, making the likelihood of growing a desirable mushroom remote. When inoculating an outdoor environment with mushroom spawn, the cultivator relinquishes much control to natural forces. There are obvious advantages and disadvantages to natural culture. First, the mushroom patch is controlled by volatile weather patterns. This also means that outdoor beds have the advantage of needing minimum maintenance. The ratio of hours spent per pound of mushrooms grown becomes quite efficient. The key to success is creating an environment wherein the planted mycelium naturally and vigorously expands. A major advantage of growing outdoors compared to growing indoors is that competitors are not concentrated in a tight space. When cultivating mushrooms outdoors entropy is your ally. The rate of growth, time to fruiting, and quality of the crop depends upon the quality of the spawn, substrate materials, and weather conditions. Generally, when mushrooms are fruiting in the wild, the inoculated patches also produce. Mushrooms that fruit primarily in the summer, such as the King Stropharia (Stropharia rugosoannulata) require frequent watering. Shaggy Manes (Coprinus comatus) prefer the cool fall rains, thus requiring little attention. In comparison to indoor cultivation, the outdoor crops are not as frequent. However, the crops can be just as intense, sometimes more so, especially when paying modest attention to the needs of the mushroom mycelium at critical junctions in its life cycle. While the cultivator is competing with molds indoors, wild mushrooms are the major competitors outdoors. You may plant one species in an environment where another species is already firmly established. This is especially likely if you use old sawdust, chips, or base materials. Starting with fresh materials is the simplest way to avoid this problem. Piles of aged wood chips commonly support four or five species of mushrooms within just a few square feet. Unless, the cultivator uses a high rate of inoculation (25% spawn/substrate) and uniformly clean wood chips, the concurrence of diverse mushroom species should be expected. If, for instance, the backyard cultivator gets mixed wood chips in the early spring from a county road maintenance crew, and uses a dilute 5–10% inoculation rate of sawdust spawn into the chips, the mushroom patch is likely to have more wild species emerging along with the desired mushrooms. In the Pacific Northwest of North America, I find a 5–10% inoculation rate usually results in some mushrooms showing late in the first year, the most substantial crops occurring in the second and third years, and a dramatic drop-off in the fourth year. As the patch ages, it is normal to see more diverse mushroom varieties cooccurring with the planted mushroom species. I am constantly fascinated by the way nature reestablishes a polyculture environment at the earliest opportunity. Some mycologists believe a predetermined sequence of mycorrhizal and saprophytic species prevails, for instance, around a Douglas fir tree, as it matures. In complex natural habitats, the interlacing of mycelial networks is common. Underneath a single tree, twenty or more species may thrive. I look forward to the time when mycotopian foresters will design whole species mosaics upon whose foundation vast ecosystems can flourish. This book will describe simpler precursor models for mixing and sequencing species. I hope imaginative and skilled cultivators will further develop these concepts. In one of my outdoor wood-chip beds, I created a “polyculture” mushroom patch about 50 by 100 feet in size. In the spring I acquired mixed wood chips from the county utility company—mostly alder and Douglas fir—and inoculated three species into it. One year after inoculation, in late April through May, Morels showed. From June to early September, King Stropharia erupted with force, providing our family with several hundred pounds. In late September through much of November, an assortment of Clustered Woodlovers (Hypholoma-like) species popped up. With noncoincident fruiting cycles, this Zen-like polyculture approach is limited only by your imagination. Species succession can be accomplished indoors. Here is one example. After Shiitake stops producing on logs or sawdust, the substrate can be broken apart, remoistened, resterilized, and reinoculated with another gourmet mushroom; in this case, I recommend Oyster mushrooms. Once the Oyster mushroom life cycle is completed, the substrate can be again sterilized, and inoculated with the next species. Shiitake, Oyster, King Stropharia, and finally Shaggy Manes can all be grown on the same substrate, increasingly reducing the substrate mass, without the addition of new materials. The majority of the substrate mass that does not evolve into gases, is regenerated into mushrooms. The conversion of substrate mass-tomushroom mass is mind boggling. These concepts are further developed in Chapter 22. The following is a list of decomposer mushrooms most frequently occurring in wood chips in the northern temperate regions of North America. In general, these natural competitors are easy to distinguish from the gourmet mushroom species described in this book. Those that are mildly poisonous are labeled with*; those that are deadly have two**. This list is by no means comprehensive. Many other species, especially the poisonous mycorrhizal Amanita, Hebeloma, Inocybe, and Cortinarius species are not listed here. Mushrooms from these genera can inhabit the same plot of ground where a cultivator may lay down wood chips, even if the host tree is far removed. The mushrooms in the Galerina autumnalis and Pholiotina filaris groups are deadly poisonous. Some species in the genus Psilocybe contain psilocybin and psilocin, compounds that often cause uncontrolled laughter, hallucinations, and sometimes spiritual experiences. Outdoor cultivators must hone their skills at mushroom identification to avert the accidental ingestion of a poisonous mushroom. Recommended mushroom field guides and mushroom identification courses are listed in the Resource Directory in this book. Some Wild Mushrooms Naturally Found in Beds of Wood Chips Ground Lovers Agrocybe spp. and Pholiota spp. The Sweaters Clitocybe spp.* The Inky Caps Coprinus atramentarius* C. comatus C. disseminatus C. lagopus C. micaceus and allies The Vomited Scrambled Egg Fungus Fuligo cristata The Deadly Galerinas Galerina autumnalis and allies** Red-Staining Lepiotas Lepiota spp.* The Clustered Woodlover Hypholoma capnoides The Green-Gilled Clustered Woodlover Hypholoma fasciculare * The Chestnut Mushroom Hypholoma sublateritium The Deadly Ringed Cone Head Pholiotina filaris and allies ** Pholiota terrestris and allies The Deer Mushroom Pluteus atrocapillus (= cervinus) Black Spored Silky Stems Psathyrella spp. The Caramel Capped Psilocybes Psilocybe cyanescens and allies Methods of Mushroom Culture Mushrooms can be cultivated through a variety of methods. Some techniques are exquisitely simple, and demand little or no technical expertise. Others—involving sterile tissue culture—are much more technically demanding. The simpler methods take little time, but also require more patience and forgiveness on the part of the cultivator, lest the mushrooms do not appear on your timetable. As one progresses to the more technically demanding methods, the probability of success is substantially increased, with mushrooms appearing exactly on the day scheduled. The simpler methods for mushroom cultivation, demanding little or no technical expertise, are outlined in this chapter. They are spore-mass inoculation, transplantation, and inoculation with pure cultured spawn. Collecting the spores of the delicious Lepiota rachodes, a Parasol Mushroom, on two panes of glass, which are then folded together, creating a spore booklet. Spore-Mass Inoculation By far the simplest way to grow mushrooms is to broadcast spores onto prepared substrates outdoors. First, spores of the desired species must be collected. Spore collection techniques vary, according to the shape, size, and type of the mushroom candidate. For gilled mushrooms, the cap can be severed from the stem, and laid, gills down, on top of clean typing paper, glass, or similar surface. A glass jar or bowl is placed over the mushroom to lessen the loss of water. After 12 hours, most mushrooms will have released thousands of spores, falling according to the radiating symmetry of the gills, in a symmetrically attractive outline called a sporeprint. This method is ideal for mushroom hunters “on the go” who might not be able to make use of the spores immediately. After the spores have fallen, the spore print can be sealed, stored, and saved for future use. It can even be mailed without harm. By collecting spores of many mushrooms, one creates a species library. Spore collections can resemble stamp or coin collections, but are potentially more valuable. A mushroom hunter may find a species only once in a lifetime. Under these circumstances, the existence of a spore print may be the only resource a cultivator has for future propagation. I prefer taking spore prints on panes of glass, using duct tape as binding along one edge. The glass panes are folded together, and masking tape is used to seal the three remaining edges. This spore booklet is then registered with written notes affixed to its face as to the name of mushroom, the date of collection, the county and locality of the find. Spores collected in this fashion remain viable for years, although viability decreases over time. They should be stored in a dark, cool location, low in humidity and free from temperature fluctuation. Techniques for creating cultures from spores are explained further on. For those wishing to begin a mushroom patch using fresh specimens, a more efficient method of spore collection is recommended. This method calls for the immersion of the mushroom in water to create a spore-mass slurry. Choose fairly mature mushrooms and submerge them in a 5-gallon bucket of water. A gram or two of table salt inhibits bacteria from growing while not substantially affecting the viability of the spores. With the addition of 50 milliliters of molasses, spores are stimulated into frenzied germination. After 4 hours of soaking, remove the mushrooms from the bucket. Most mushrooms will have released tens of thousands of spores. Allow the broth to sit for 24 to 48 hours at a temperature above 50°F (10°C) but under 80°F (26.7°C). In most cases, spores begin to germinate in minutes to hours, aggressively in search of new mates and nutrients. This slurry can be expanded by a factor of 10 in 48 hours. I have often dreamed, being the mad scientist that I am, of using spore-mass slurries of Morels and other species to aerially “bomb” large expanses of forestlands. This idea, as crazy as it may initially sound, warrants serious investigation. During this stage of frenzied spore germination, the mushroom patch habitat should be designed and constructed. Each species has unique requirements for substrate components for fruiting. However, mycelia of most species will run through a variety of lignin-cellulosic wastes. Only at the stage when fruitbody production is sought does the precise formulation of the substrate become crucial. Oyster (Pleurotus ostreatus; P. eryngii, and allies), King Stropharia (Stropharia rugosoannulata), and Shaggy Mane (Coprinus comatus) mushrooms thrive in a broad range of substrate formulations. Other mushrooms such as Morels (Morchella angusticeps and esculenta) are more restrictive in their requirements. Since there are several tracks that one can pursue to create suitable habitats, refer to Chapter 21 for more information. Transplantation: Mining Mycelium from Wild Patches Transplantation is the moving of mycelium from natural patches to new habitats. Most wild mushroom patches have a vast mycelial network emanating from beneath each mushroom. Not only can one harvest the mushroom, but portions of the mycelial network can be gathered and transferred to a new location. This method ensures the quick establishment of a new colony without having to germinate spores or buy commercial spawn. When transplanting mycelium, I use a paper sack or a cardboard box. Once mycelium is disturbed, it quickly dries out unless measures are taken to prevent dehydration. After it is removed from its original habitat, the mycelium will remain viable for days or weeks, as long as it is kept moist in a cool, dark place. Gathering the wild mycelium of mycorrhizal mushrooms could endanger the parent colony. Be sure you cover the divot with wood debris and press tightly back into place. In my opinion, mycorrhizal species should not be transplanted unless the parent colony is imminently threatened with loss of habitat—such as logging, construction, etc. Digging up mycelium from the root zone of a healthy forest can jeopardize the symbiotic relationship between the mushroom and its host tree. Exposed mycelium and roots become vulnerable to disease, insect invasion, and dehydration. Furthermore, transplantation of mycorrhizal species has a lower success rate than the transplantation of saprophytic mushrooms. If done properly, transplanting the mycelium of saprophytic mushrooms is not threatening to naturally occurring mushroom colonies. Some of the best sites for finding mycelium for transplantation are sawdust piles. Mycelial networks running through sawdust piles tend to be vast and relatively clean of competing fungi. Fans of mycelium are more often found along the periphery of sawdust piles than within their depths. When sawdust piles are a foot deep or more, the microclimate is better suited for molds and thermophilic fungi. These mold fungi benefit from the high carbon dioxide and heat generated from natural composting. At depths of 2–6 inches, mushroom mycelia run vigorously. It is from these areas that mushroom mycelium should be collected for transplantation to new locations. One, in effect, engages in a form of mycelial mining by encouraging the growth and the harvesting of mycelium from such environments. Ideal locations for finding such colonies are sawmills, nurseries, composting sites, recycling centers, rose and rhododendron gardens, and soil mixing companies. Establishing an outdoor mushroom bed in a garden. Sprinkling spawn on top of mulch layer. Adding more moist mulch over the spawn layer. Cross section of garden bed showing mycelium and mushroom growth. Inoculating Outdoor Substrates with Pure Cultured Spawn In the early history of mushroom cultivation, mycelium was collected from the wild and transplanted into new substrates with varying results. Soon compost spawn (for the Button Mushroom, Agaricus brunnescens) evolved with greater success. In 1933, spawn technology was revolutionized by Sinden’s discovery of grain as a spawn carrier medium. Likewise, Stoller (1962) significantly contributed to the technology of mushroom cultivation through a series of practical advances in using plastic bags, collars, and filters.1 The Mushroom Cultivator (Stamets and Chilton, 1983) explained the process of producing tissue culture for spawn generation, empowering far more cultivators than ever before. Legions of creative individuals embarked on the path of exotic mushroom production. Today, thousands of cultivators are contributing to an ever-expanding body of knowledge, and setting the stage for the cultivation of many gourmet and medicinal fungi of the future. The advantage of using commercial spawn is in acquiring mycelium of higher purity than can be harvested from nature. Commercial spawn can be bought in two forms: grain or wood (sawdust or plugs). For the inoculation of outdoor, unpasteurized substrates, wood-based spawn is far better than grain spawn. When grain spawn is introduced to an outdoor bed, insects, birds, and slugs quickly seek out the nutritious kernels for food. Sawdust spawn has the added advantage of having more particles or inoculation points per pound than does grain. With more points of inoculation, colonization is accelerated. The distances between mycelial fragments are lessened, making the time to contact less than that with grain spawn. Thus the window of vulnerability is closed to many of the diseases that eagerly await intrusion. Before spawn is used, the receiving habitat is moistened to near saturation. The spawn is then mixed thoroughly through the new habitat with your fingers or a rake. Once inoculated, the new bed is again watered. The bed can be covered with cardboard, shade cloth, scrap wood, or a similar material to protect the mycelium from sun exposure and dehydration. After inoculation, the bed is ignored, save for an occasional inspection and watering once a week, and then only when deemed necessary. Certain limitations prevail in the expansion of mycelium and its ability for colonizing new substrates. The intensity or rate of inoculation is extremely important. If the spawn is too dispersed into the substrate, the points of inoculation will not be close enough to result in the rapid reestablishment of one large contiguous mycelial mat. My own experiences show that success is seen with an inoculation rate of 5–50%, with an ideal of 20%. In other words, if you gather a 5-gallon bucket of naturally occurring mycelium, 20 gallons of prepared substrate can be inoculated with a high probability of success. Although this inoculation rate may seem high, rapid colonization is assured. More skilled cultivators, whose methods have been refined through experience, often use a less intensive inoculation rate of 10%. Inoculation rates of 5% or less often result in “island” colonies of the implanted species interspersed among naturally occurring wild colonies. At a 20% inoculation rate, colonization can be complete in as short as 1 week and as long as 8 weeks. After a new mycelial mat has been fully established, the cultivator has the option of further expanding the colony by a factor of 5, or triggering the patch into fruiting. This usually means providing shade and frequent watering. Should prevailing weather conditions not be conducive to fruiting and yet are above freezing, then the patch can be further expanded. Should the cultivator not expect that further expansion would result in full colonization by the onset of winter, then no new raw material should be added, and mushrooms should be encouraged to form. The widely cast mycelial mat, more often than not, acts as a single organism. At the time when mushrooms are forming, colonization of new organic debris declines or abates entirely. The energy of the mycelium is now channeled to fruitbody formation and development. Healthy Stropharia rugosoannulata mycelium tenaciously gripping alder chips and sawdust. Note rhizomorphs. From the same patch, a year later, the wood chips have decomposed into a rich soilloam. The mycelium of saprophytic mushrooms must move to remain healthy. When the mycelium reaches the borders of a geographically or nutritionally defined habitat, a resting period ensues. If not soon triggered into fruiting, over-incubation is likely, with the danger of “dieback.” Only very cold temperatures will keep the patch viable for a prolonged period. Typically, dieback is seen as the drastic decline in vigor of the mycelium. Once the window of opportunity has passed for fruiting, the mushroom patch might be salvaged by the reintroduction of more undecomposed organic matter, or by violent disturbance. The mycelium soon becomes a site for contamination with secondary decomposers (weed fungi) and predators (insects) coming into play. It is far better is to keep the mycelium running until fruitings can be triggered at the most opportune time. Mushroom patches are, by definition, temporary communities. King Stropharia lasts 3 to 4 years on a hardwood chip base. After the second year more material should be added. However, if the health of the patch has declined and new material is mixed in, then the mushroom patch may not recover to its original state of vigor. Mycelium that is healthy tends to be tenacious, holding the substrate particles together. This is especially true with Stropharia spp. and Oyster mushrooms. (Hericium erinaceus and Morchella spp. are exceptions.) Over-incubation results in a weakened mycelial network whereby the mycelium is incapable of holding various substrate particles together. As mycelial integrity declines, other decomposers are activated. Often, when mixing in new material at this stage, weed fungi proliferate to the decided disadvantage of the selected gourmet species. To the eye, the colony no longer looks like a continuous sheet of mycelium, but becomes spotty in its growth pattern. Soon islands of mycelia become smaller and smaller as they retreat, eventually disappearing altogether. The only recourse is to begin anew, scraping away the now-darkened wood/soil, and replacing it with a new layer of wood chips and/or other organic debris. When to Inoculate an Outdoor Mushroom Patch Outdoor beds can be inoculated in early spring to early fall. The key to a mushroom bed is that the mycelium has sufficient time to establish a substantial mycelial mat before the onset of inclement weather conditions. Springtime is generally the best time to inoculate, especially for creating large mushroom patches. As fall approaches, more modestly sized beds should be established, with a correspondingly higher rate of inoculation for faster growth. For most saprophytic species, at least 4 weeks are required to form the mycelial network with the critical mass necessary to survive the winter. Most woodland species survive wintering temperatures. Temperate woodland mushrooms have evolved protective mechanisms within their cellular network that allow them to tolerate cold temperature extremes. Surface frosts usually do not harm the terrestrially bound mushroom mycelium. As the mycelium decomposes organic matter, heat is released, which benefits subsurface mycelium. Mycelial colonization essentially stops when outdoor temperatures fall below freezing. Site Location of a Mushroom Patch A suitable site for a mushroom patch is easy to choose. The best clue is to simply take note of where you have seen mushrooms growing during the rainy season. Or just observe where water traverses after a heavy rain. A gentle slope, bordered by shrubs and other shadegiving plants, is usually ideal. Since saprophytic mushrooms are noncompetitive to neighboring plants, they pose no danger to them. In fact, plants near a mushroom bed often thrive—the result of the increased moisture retention and the release of nutrients into the root zone. An ideal location for growing mushrooms is in a vegetable, flower, and/or rhododendron garden. Gardens are favored by plentiful watering, and the shade provided by potato, zucchini, and similar broadleaf vegetable plants tend to keep humidity high near the ground. Many gardeners bring in sawdust and wood chips to make pathways between the rows of vegetables. By increasing the breadth of these pathways, or by creating small cul-de-sacs in the midst of the garden, a mushroom bed can be ideally located and maintained. Other suitable locations are exposed north sides of buildings, and against rock, brick, or cement walls. Walls are usually heat sinks, causing condensation, which provides moisture to the mushroom site as temperature fluctuates from day to night. Protected from winds, these locations have limited loss of water due to evaporation. Mushrooms love moisture. By locating a mushroom bed where moisture naturally collects, colonization is rapid and more complete, and the need for additional water for fruiting is minimized. The message here: Choose your locations with moisture foremost in mind. Choose shady locations over sunny ones. Choose north-facing slopes rather than south facing. Choose companion plants with broad leaves or canopies that shade the midday sun but allow rain to pass. The difference in results is the difference between a bountiful success or dismal failure. Giant Oyster mushrooms fruiting from a stump. Stumps as Platforms for Growing Mushrooms Stumps are especially suitable for growing gourmet mushrooms. There are few better, or more massive platforms, than the stump. Millions of stumps are all that remain of many forests of the world. In most cases, stumps are seen as having little or no economic potential. These lone tombstones of biodegradable wood fiber offer a unique, new opportunity for the mycologically astute. With selective logging being increasingly practiced, cultivating gourmet and medicinal mushrooms on stumps will be the wave of the future. The advantage of the stump is not only its sheer mass, but with roots intact, water is continuously being drawn via capillary action. Once mycelium has permeated through wood fiber, the stump’s water-carrying capacity is increased, thus further supporting mycelial growth. Candidates for stump culture must be carefully selected and matched with the appropriate species. A stump partially or fully shaded is obviously better than one in full sunlight. Stumps in ravines are better candidates than those located in the center of a clear-cut area. An uprooted stump is not as good a candidate as a well-rooted one. The presence of mosses, lichens, and/or ferns is a good indicator that the microclimate is conducive to mushroom growth. However, the presence of competitor fungi generally disqualifies a stump as a good candidate. These are some of the many factors that determine the suitability of stumpage. Cultivating mushrooms on stumps requires forethought. Stumps should be inoculated before the first season of wild mushrooms. With each mushroom season, the air becomes laden with spores, seeking new habitats. The open face of a stump, essentially a wound, is highly susceptible to colonization by wild mushrooms. With the spore cast from wild competitors, the likelihood of introducing your species of choice is greatly reduced. If stumps are not inoculated within several months of being cut, the probability of success decreases. Therefore, old stumps are poor candidates. Even so, years may pass after inoculation before mushrooms form on a stump. But once a colony begins, the same species may predominate for many years. Large-diameter stumps can harbor many communities of mushrooms. On old-growth or second-growth Douglas fir stumps common to the forests of Washington State, finding several species of mushrooms is not unusual. This natural example of “polyculture”—the simultaneous concurrence of more than one species in a single habitat—should encourage experimentally inclined cultivators. Mushroom landscapes of great complexity could be designed. However, the occurrence of poisonous mushrooms should be expected. Two notable toxic mushrooms frequent stumps: Hypholoma fasciculare (=Naematoloma fasciculare) which causes gastrointestinal upset but usually not death, and Galerina autumnalis, a mushroom that does kill. Because of the similarity in appearance between Flammulina velutipes (Enoki) and Galerina autumnalis, I hesitate to recommend the cultivation of Enoki mushrooms on stumps unless the cultivator is adept at identification. (To learn how to identify mushrooms, please refer to the recommended mushroom field guides listed in Appendix 4.) Several polypores are especially good candidates for stump cultivation, particularly Grifola frondosa, Maitake, Ganoderma lucidum, Reishi, and its close relatives. As the antiviral and anticancer properties of these mushrooms become better understood, new strategies for the cultivation of medicinal mushrooms will be developed. I envision the establishment of Maitake and Reishi mushroom tree farms wherein stumps are purposely created and selectively inoculated for maximum mushroom growth, interspersed among shade trees. Once these models are perfected, other species can be incorporated in creating a multicanopy medicinal forest. Drilling and inoculating a stump with plug spawn. Small-diameter stumps rot faster and produce crops of mushrooms sooner than bigger stumps. However, the smaller stump has a shorter mushroom-producing life span than the older stump. Often with large-diameter stumps, mushroom formation is triggered when competitors are encountered and/or coupled with wet weather conditions. The fastest I know of a stump producing mushrooms from time of inoculation is 8 weeks. In this case, an oak stump was inoculated with plug spawn of Chicken-of-the-Woods, Laetiporus (Polyporus) sulphureus. Notably, the stump face was checkered, with multiple fissures running vertically through the innermost regions of the wood. These fissures trapped water from rainfall and promoted fast mycelial growth. Another technique that improves success rates is to girdle the stump with a chain saw, interrupting direct contact between the root zone and the above-air portion. A local mycological society found that all their inoculated stumps produced which were girdled compared to a small fraction for those that were not. As with the growing of any mushrooms, the speed of colonization is a determining factor in the eventual success or failure of any cultivation project. For foresters and ecologists, actively inoculating and rotting stumps has several obvious advantages. Rather than allowing a stump to be randomly decomposed, species of economic or ecological significance can be introduced. For instance, a number of Honey mushrooms, belonging to the genus Armillaria, can operate as both saprophytes or parasites. Should clear-cuts become colonized with these deadly, root-rotting species, satellite colonies can be spread to adjacent living trees. Now that burning is increasingly restricted because of air pollution concerns, disease vectors coming from stumpage could present a new as-yet-unmeasured threat to the forest ecosystem. The Honey mushroom, Armillariella mellea, growing on a fir stump in a rhododendron garden, an ideal locus for creating a mycological landscape. The advantages of growing on stumps can be summarized as Developing a new, environmentally friendly wood products industry. Recycling wood debris of little or no economic value. Prevention of disease vectors from parasitic fungi. The rapid return of wood debris back into a nutritious food for the benefit of other citizens of the forest. Since the food chain is accelerated and enriched, ecosystems are invigorated. Few studies have been published on recycling stumps with mushrooms. One notable work from Eastern Europe, published by Pagony (1973), describes the cultivation of Oyster mushrooms (Pleurotus ostreatus) on large-diameter poplars with a 100% success rate. Inoculations in the spring resulted in fruitings appearing the ensuing fall, and continued for several years hence. An average of 4 pounds of Oyster mushrooms were harvested over 4 years (i.e., 1 pound/year/stump). Hilber (1982) also reported on the utility of using natural wood (logs and stumps) for growing Oyster mushrooms, and that per cubic meter of elm wood, the yield from one season averaged 17–22 kilograms. A study in France by Anselmi and Deandrea (1979), where poplar and willow stumps were inoculated with spawn of the Oyster mushroom, showed that this mushroom favored wood from newly felled trees, in zones that received speckled sunlight. This study confirmed that Pleurotus ostreatus only attacked deadwood and never became parasitic. Their study supports my opinion (Stamets, 1990) that the purposeful inoculation of stumps can forestall the invasion by parasites like Honey mushrooms of the Armillaria mellea complex. Mushrooms of this group first kill their host and then continue to live saprophytically. A stump with Honey mushrooms can later destroy neighboring living trees. In Washington State, one colony of Honey mushrooms is blamed for destroying thousands of acres of conifers. Inoculating a stump with the wedge and the spawn disk technique. Stumps can be inoculated by one of several simple procedures. Plug spawn can be inserted into the open face of each stump. If the stumps are checkered through with cracks, the plugs are best inserted directly into the fissures. Another method is known as the wedge or disk inoculation technique. With a chain saw, a wedge is cut or a shallow disk is sliced from the open face of the stump. The newly cut faces are packed with sawdust spawn. The cut disk is then replaced. By hammering a few nails into the stump, you can assure firm contact between the cut faces. Another method I have developed is to add spores to biodegradable chainsaw oil so that as trees are being cut, the stumps are inoculated. (Patent pending). Plug spawn of Shiitake. Spirally grooved wooden dowels help the mycelium survive from the concussion of inoculation. The broadleaf hardwoods are easier to saprophytize with the gourmet and medicinal mushroom species described in this book than the softwood pines. And within the hardwood group, the rapidly growing species such as the alders and poplars decompose more rapidly—and hence give an earlier crop—than the denser hardwoods such as the oaks. However, the denser and more massive stumps sustain colonies of mushrooms for many more years than the quick-to-rot, smaller-diameter tree species. In a colonial graveyard in New York state, a four-foot-diameter oak has consistently produced clusters of Maitake mushrooms, sometimes weighing up to 100 pounds apiece, for more than 20 years! See this image. Inoculating stumps with strains cloned from native mushrooms is favored over the use of exotic fungi. Spring inoculations give the mycelium the longest possible growing season. Stump cultivation has tremendous potential. These unexploited resources can become production sites of gourmet and medicinal mushrooms. Although more studies are needed to ascertain the proper matching of species to the wood types, I encourage you to experiment. Only a few minutes are required to inoculate a stump or dead tree. The potential rewards could span a lifetime. The “soak and strike” method for initiating Shiitake. Figure 14. Natural culture of Shiitake in the mountains of Japan. (Photographs, both from Mimura, Japan, circa 1915.) Log Culture Log culture was developed in Japan and China more than a millennium ago. Even today, thousands of small-scale Shiitake growers use log culture to provide the majority of mushrooms sold to markets. In their backyards and along hillsides, inoculated logs are stacked like cordwood or in fence-like rows. These growers supply local markets, generating a secondary income for their families. Attempts to reproduce this model of Shiitake cultivation in North America and Europe has met with modest success. The advantage of log culture is that it is a simple and natural method. The disadvantage is that the process is labor-intensive, and slow in comparison to growing mushrooms on sterilized sawdust. Besides Shiitake, many other mushrooms can be grown on logs, including Nameko (Pholiota nameko), all the true Oyster mushrooms (Pleurotus and Hypsizygus spp.), Lion’s Mane (Hericium erinaceus), Wood Ears (Auricularia auricula), Clustered Woodlovers (Hypholoma capnoi