July/August 1993

Mushrooms:
A Fine Agricultural Crop

During the last 30 years, mushroom production has increased 20-fold. According to Dr. Philip Miles, professor of biology at State University of New York in Buffalo, worldwide production of phoenix tail oyster mushrooms, Pleurotus sajor-caju, has exploded. The most recent statistics show 909,000 metric tons of production, mostly in mainland China. Shiitake has become a worldwide, multi-billion dollar industry. During the 1980s, it was the number one agricultural crop exported from Japan to the international market. In Asian countries, an everyday meal at home may consist of 30 percent mushrooms. I am convinced that the consumer demand for exotic mushrooms in this country also promises a diverse and growing mushroom market in the future.

Many cultivated species are sold in specialty shops and supermarkets. The Monterey Market in Berkeley carries over 10 different types of fresh edible fungi grown by local small farmers. Recent retail prices of mushrooms at Monterey Market were as follows:

Type Price per pound

Shiitake $5.89 to $11.50

Oyster $3.98

Matsutake $19.00

White truffles $75.00

Black truffles $135.00

Of these five species, only shiitake and oyster mushrooms are domesticated. Matsutake and truffles are wild. They must interact with trees and wild animals in the woodlots in which they grow.

Many levels of production are possible

Mushrooms can be grown by anyone, from backyard gardeners to large-scale corporations. They do not require arable land, special light, or large amounts of water. Mushrooms do not compete with other plants, and even enhance the growth of many plants.

Mushrooms can be cultivated in agar, boiled straw, compost, on logs and stumps, even in the lawn. They can be grown outdoors or indoors. "Just-add-water" kits or spawn raised under laboratory conditions are available.

The mushroom life cycle is not only shorter than many crops (six to seven weeks for one shiitake crop), but the yield is very high.

California's environment is
excellent for mushroom cultivation

California has excellent climatic and topographical conditions for growing mushrooms. A variety of mushrooms can be grown from coastal range areas to the Sierra Nevada Mountain forests. Due to the cool moist winter in northern California, mushrooms can be grown outside yearlong. They can be grown indoors in incubation and growing houses. California oak is excellent for growing log mushrooms.

California also offers social and market benefits as more people become health conscious and interested in the medicinal values of mushrooms and other fungi and herbs. There are more than 86 edible fungi species, 42 of which have medicinal value, that grow in the Bay area of California. I am now compiling a handbook on these wild mushrooms. There is great potential for domestication of many of these species.

Recycling of agriculture
and forest waste

Many low-grade agricultural waste products can be used for mushroom cultivation, including the stalks of agricultural produce, corn cobs, cotton shells, sugar cane segments, sugar beets, methane, industry waste from cotton mills, slaughterhouses, meat processing plants, and paper factories, and sewage from livestock feedlots. Cellulose and some nutrients must be added to the waste materials to foster rapid growth.

According to the Food and Agriculture Organization, about 20 million tons of usable agricultural "waste" are discarded each year. An English researcher found that developed countries burn about 60 percent of usable waste products every year. Recycling waste products for mushroom cultivation is one method of conservation in this era of great concern for our natural resources. Oak sawdust, a waste product in many American forests, is an excellent substance for shiitake mushrooms. Much of this valuable resource is burned each year. For East Asian farmers, mushroom production is an important part of their sustainable agriculture system.

Not only do mushrooms provide food, but mushroom waste can be recycled into fertilizers and additives that improve tree plantation soil conditions.

Nutritional and medicinal value
of mushrooms

Besides their diverse and interesting culinary uses, mushrooms have nutritional and medicinal value. Some mushrooms contain cancer-fighting properties and some aid the body's immune system. Shiitake mushrooms and other fungi are good sources of protein, vitamins, and minerals. Shiitake contains proteins, lipids, and carbohydrates; vitamins A, B1, B2, C, D2; niacin, phosphorus, iron, calcium, and other minerals. According to Dr. Kanichi Mori, shiitake mushrooms lower serum cholesterol, have strong anti-tumor and anti-viral properties, very low fat, no starch, and more vitamin B12 than milk and fish. He considers shiitake nutritionally more valuable than the western staples corn, turnips, potatoes, tomatoes, and carrots. Although they have less protein than meat, the amount is comparable to peas and green beans.

Edible mushroom varieties

The Chinese have cultivated mushrooms for centuries. Of the 300 edible mushroom species (including 294 basidiomycotina and six ascomycotina) about 30 have been domesticated. Only about 10 species can be commercially mass grown because of the genetic difficulties in artificial growing. These 10 species are:

Common name Scientific name

button Agaricus bisporus

shiitake Lentinus edodes

enoki Flammulina velutipes

straw Volvariella volvacea

common oyster Pleurotus ostreatus

phoenix tail Pleurotus sajor-caju

oyster Pleurotus abolonus

golden top oyster Pleurotus citrinopileatu

bear head Hericium erinaceus

wood ear Auricularia auricula

hair wood ear Auricularia polutricha

silver ear Tremella fuciformis

ling zhi Ganoderma lucidum

The need for education and
research

Mushroom growers need both experience and education. Mushrooms are often thought of as an easy crop to produce with a high price potential. People often find mushroom cultivation is not as easy as they thought it would be. Much of the necessary knowledge must be acquired through practical experience, but understanding the principles of mushroom cultivation demystifies the process, allowing the grower to successfully adapt and develop cultivation methods.

The author:

Dr. Mo-mei Chen is a professor of forest pathology, mycology, and biogeography at the Chinese Academy of Forestry. She has been a mushroom business production consultant for 20 years. In 1980 she studied shiitake production at the Tottori Mycological Institute (Shiitake Research Center), Japan. Since 1986 she has contributed her mushroom knowledge and expertise to the Bay Area. Dr. Chen is currently a visiting professor at UC Berkeley, Dept. of Plant Pathology, and a consultant at Bio-Integral Resource Center's China Project, Berkeley. She can be reached at the Department of Plant Pathology, Universtiy of California, Berkeley, CA 94720.

Suppliers

Fungi Perfecti
P.O. Box 7634
Olympia, WA 98507
(206) 426-9292

Far West Fungi
P.O. Box 428
South San Francisco, CA 94083
(415) 871-0786

Cultivation information

Growing mushrooms (button mushrooms), ANR publication 2640, available for $1.50 from ANR Publications, 6701 San Pablo Avenue, Oakland, CA 94608-1239. (8 pages)

Mushrooms (a small-scale agriculture alternative) (shiitake mushrooms), available free from the Small Farm Center. (2 pages)

Stamets P., and J.S. Chilton. The Mushroom Cultivator: a practical guide to growing mushrooms at home. Agarikon Press, Olympia Washington. 1983. (415 pages). Available from Fungi Perfecti (see suppliers above).