Oyster Mushrooms

Oyster mushrooms (Pleurotus species) are a good choice for beginning mushroom cultivators because they are easier to grow than many of the other species, and they can be grown on a small scale with a moderate initial investment. Although commonly grown on sterile straw from wheat or rice, they will also grow on a wide variety of high-cellulose waste materials. Some of these materials do not require sterilization, only pasteurization, which is less expensive. Another advantage of growing oyster mushrooms is that a high percentage of the substrate converts to fruiting bodies, increasing the potential profitability.

Oyster mushrooms can become an integral part of a sustainable agriculture system. Many types of organic wastes from crop production or the food processing industry can be used to support oyster mushroom production.

Although there are no books devoted entirely to oyster mushroom production, Stamets' books provide basic information. Research on using various agricultural and forest wastes as substrates is reported in the recently published Mushroom Biology and Mushroom Products, edited by D.J. Royse. Peter Oei documents a number of commercial production systems for some strains grown in developing countries.

There are an increasing number of Web sites devoted to oyster mushroom production. Lawrence Weingarten describes his production process on his Web site, complete with photos at
http://www.mycowest.org/cult/i-grow/i-grow-1.htm.

A Canadian Web site also offers additional advice:
Oyster Mushroom Cultivation (Site http://www.gov.ns.ca/nsaf/elibrary/archive/hort/vegetables/pihve94-03.htm no longer active.)

The MushWorld Web site, contains excellent technical information about growing oyster mushrooms. The site requires registration, but it is free.

Oyster mushroom cultivation has one significant drawback: some people are allergic to the spores. In these cases, air-cleaning equipment or respirators are necessary in order to safely work in the production facility.

The consumer market for oyster mushrooms is being developed by the larger mushroom companies as they diversify their operations. However, because of the short shelf life of many oyster mushroom varieties, this species may offer a special advantage to the local grower who markets directly and can consistently deliver a fresh, high-quality product.

Choosing a Mushroom Species

A mushroom cultivation kit is a handy way to begin to understand the fungal life cycle. Once you successfully use the kit, you can begin to learn the steps that precede that final fruiting stage of the mushroom life cycle. Purchase spawn that will grow on materials you have available. Then design and test a system that duplicates the conditions favorable to all stages of growth. You can use this experience to learn how to create sterile cultures and spawn for the species you are growing.

Choose the species to grow by thinking about:
What waste materials are readily available to use as a growth medium?
What kind of facility or environment is available?
How much will the necessary equipment cost?
What level of skill is required to manage the life cycle of the fungus?
What is market demand for this species?

According to these criteria, oyster (Pleurotus species) and shiitake (Lentinus edodes) mushrooms are probably best for most novices, although the maitake (Grifola frondosa) is also a possibility. The former two are relatively easy to grow, and there is already a market for them, largely because commercial producers of white button (Agaricus bisporus) mushrooms have been diversifying into specialty mushrooms. If you intend to grow mushrooms commercially, shiitake or oyster mushrooms are your best choices. These two species are more thoroughly covered in the following sections.

A chart in the Appendix lists other common species and the materials on which they can be cultivated. Test each species you are considering against each of the questions listed above.

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Mushrooms on the Farm and in the Garden

Fungi cycle nutrients that nourish new life in the soil. Recognizing this essential function, inventive gardeners integrate mushrooms into farm, garden, and permaculture systems. Mushrooms can also be grown in lawns, polytunnels, vegetable gardens, and woodlands.

Terri Marie Beauséjour, a writer for Mushroom the Journal, encourages creativity and imagination when planting mushrooms in a garden. Look at the "fungamentals," she writes, the necessities such as available substrates, microhabitats, sun, shade, wind, and humidity conditions. Gardens offer ample substrates—organic waste materials—while plants provide shade and humidity. Plug-inoculated blocks buried among plantings work well for oyster and Stropharia rugoso-annulata mushrooms. Beauséjour suggests using a misting sprinkler for mushrooms in gardens.

Grower and author Ken Litchfield notes that mulching, a standard gardening practice, not only regulates soil temperature and humidity but also nourishes fungi. He also suggests surrounding raised beds with partially buried logs to create mushroom habitats. Inside the beds, vegetables, flowers, and shrubs offer the requisite shade and humidity for mushroom cultivation. In weedy areas, Litchfield suggests putting down organic material and covering it with wet cardboard and wood chips, an ideal substrate for fungi.

These methods of production are not likely to yield huge numbers of mushrooms. However, they can provide an attractive addition to directly marketed produce.

Mushrooms in Permaculture* Design

*Permaculture is a system of combining perennials, trees, shrubs, and vines to create a "permanent agriculture." Using an intensive design process, the natural elements of an ecosystem are replaced by food-producing relatives, creating an edible landscape.

Paul Stamets was an early advocate of integrating a variety of mushrooms into a permaculture system. In his design, agricultural wastes like cornstalks, wheat straw, or rice straw can be used as growing media for oyster mushrooms. After harvest, the spent substrate can be recycled as fodder or mulch for garden soils.

Shaggy manes (Coprinus comatus), Stamets notes, do well on manured soils and near compost piles. The King stropharia or wine cap mushroom (Stropharia rugoso-annulata) grows best outdoors and plays a key role as a recycler of woody debris. Bees, attracted to the sweet mycelium, help pollinate the green garden plants. The mushrooms are good to eat when small. Large, mature mushrooms attract fly larvae that make excellent fish or poultry food. These can supplement feed for other on-farm enterprises or be sold to pet stores.

Stamets also uses King stropharia mushrooms for their ecological benefits. He found that, when established along waterways, they acted as microfilters of fecal coliform bacteria generated by his small herd of cattle. He also planted them along greywater runoff areas. Stamets believes mushrooms can play a large role in mycofiltration.

Stamets grows shiitakes, namekos (Pholiota nameko), and Lion’s mane (Hericium erinaceus) mushrooms on inoculated logs set in a fence row, while other species like maitake (Grifola frondosa), reishi (Ganoderma lucidum), and clustered wood-lovers are cultivated on stumps as part of a hardwood forest management system. He introduces mycorrhizal species such as chanterelles, King boletes, and others to new areas by "satellite planting," in which seedlings are planted near trees that have a desired mushroom species growing around them. After several years, the seedlings and their mycorhizal associates are transplanted, creating new patches of mushrooms. Morels are more difficult to propagate, but some types can be encouraged through the use of small burns.

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Growing Mushrooms

Mushroom production is completely different from growing green plants. Mushrooms do not contain chlorophyll and therefore depend on other plant material (the "substrate") for their food. The part of the organism that we see and call a mushroom is really just the fruiting body. Unseen is the mycelium—tiny threads that grow throughout the substrate and collect nutrients by breaking down the organic material. This is the main body of the mushroom. Generally, each mushroom species prefers a particular growing medium, although some species can grow on a wide range of materials.

If you are considering mushroom production, become thoroughly familiar with the life cycles of fungi. A very general description is included below. A plant pathology textbook is a good resource for learning more about these complex life cycles.

Once you are familiar with the various fungi life cycles, learn the growth requirements of each of the species you are considering. Two basic references are The Mushroom Cultivator, by Stamets and Chilton, and the aforementioned Growing Gourmet and Medicinal Mushrooms by Stamets (See Resources).

Growing mushrooms outdoors as a part of a market garden involves little effort after you have inoculated the logs or other substrate with the mushroom spawn. Your duties are mainly to maintain humidity and monitor for fruiting. When mushrooms appear, you add them to your other garden products and sell them. (See Mushrooms on the Farm and in the Garden, Below)

Most available markets, however, require more mushrooms than occasional fruiting provides. Indoor production can fill the gaps when outside fruiting lags. The entire operation can also be conducted inside. However, indoor mushroom production demands a much higher level of knowledge, continuous monitoring, and timely manipulation of environmental conditions.

These are the steps in mushroom production—a cycle that takes about 15 weeks (time varies by species) from start to finish.

• Choosing a growing medium
• Pasteurizing or sterilizing the medium
• Seeding the beds with spawn (material from mature mushrooms grown on sterile media)
• Maintaining optimal temperature, moisture, and other conditions for mycelium growth and the conditions that favor fruiting (This is the most challenging step.)
• Harvesting, packaging, and selling the mushrooms
• Cleaning the facility and beginning again

The substrate on which the mushrooms will fruit must be sterilized or pasteurized in order to destroy any fungal and/or bacterial competitors. Low-tech substrate preparation methods are described in the books by Paul Stamets and by Peter Oei (See Resources).

To produce spawn, you inoculate a pasteurized medium, usually grain, with the sterile culture of a particular mushroom species. After the culture has grown throughout the medium, it is called spawn. Producing spawn requires exacting laboratory procedures. Terri Marie Beauséjour, cultivation chair for the Mycological Society of San Francisco, has written an excellent article that can help the beginner who is put off by the technical aspects of mushroom cultivation. Titled "Getting Started with Mushroom Cultivation: The Wisdom of Simplicity," it is available on the Web at www.mykoweb.com/articles/cultivation.html.

Many mushroom suppliers sell several kinds of spawn, and the beginning mushroom farmer should take advantage of this selection in early trials to determine which species grow best on available materials. Eventually, learning to produce spawn might reduce your cost of production. Evaluate this possibility only after you have mastered the later stages of cultivation.

While the mycelium is growing—and until it fully occupies the substrate—the mushroom farmer typically manipulates the growing environment to favor mycelial growth. The atmospheric conditions are then changed to initiate "pinheads," and then to complete fruiting. For example, in oyster mushroom production under closely controlled conditions, the grower lowers the temperature and the CO2 in the grow room to initiate fruiting. Each species has specific requirements for its stages of development. The Mushroom Cultivator provides detailed information on the requirements for 16 species.

When you can cut the time between harvests, annual production increases. Short cycles are what the large-scale commercial producers aim for, constantly looking for ways to increase efficiency. This is the competition you face if you plan to sell your product on the wholesale market.

Paul Stamets of Fungi Perfecti, an educational and mushroom supply company
(See Recources), has spent most of his life studying the growth and cultivation of fungi. His book Growing Gourmet & Medicinal Mushrooms (See Recources) is an invaluable resource for anyone considering the cultivation of any mushroom species. He describes several alternative methods of producing mushrooms, including growing them outdoors on logs, on stumps, and in the garden, as well as indoors in bags or on columns.

Peter Oei, in Manual on Mushroom Cultivation (See Recources), describes in some detail how alternative mushroom production systems have been used successfully in developing countries. Many ideas for low-input systems are included. In practice, it is unlikely that the beginner can successfully compete in the wholesale market against highly capitalized and efficient mushroom companies. A better choice for the beginner is to develop a niche market for high-quality fresh mushrooms, then sell them at retail, or to produce a value-added mushroom product, such as a soup mix or sauce.
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Introduction

Small-scale mushroom production represents an opportunity for farmers interested in an additional enterprise and is a specialty option for farmers without much land. This publication is designed for market gardeners who want to incorporate mushrooms into their systems and for those farmers who want to use mushroom cultivation as a way to extract value from woodlot thinnings and other "waste" materials. Mushroom production can play an important role in managing farm organic wastes when agricultural and food processing by-products are used as growing media for edible fungi. The spent substrate can then be composted and applied directly back to the soil. This publication includes resources for entrepreneurs who wish to do further research.

Many people are intrigued by mushrooms nutritional and medicinal properties, in addition to their culinary appeal. Mushrooms contain many essential amino acids; white button mushrooms, for example, contain more protein than kidney beans. Shiitake mushrooms are less nutritious, but are still a good source of protein. As a group, mushrooms also contain some unsaturated fatty acids, provide several of the B vitamins, and vitamin D. Some even contain significant vitamin C, as well as the minerals potassium, phosphorus, calcium, and magnesium.

Asian traditions maintain that some specialty mushrooms provide health benefits. Chinese doctors use at least 50 species. Two recent books, Medicinal Mushrooms: An Exploration of Tradition, Healing and Culture and Medicinal Mushrooms You Can Grow, detail existing research on the health benefits of mushrooms. See the Resource section at the end of this guide for specifics on these books and other sources of information

Producing nutritious food at a profit, while using materials that would otherwise be considered "waste," constitutes a valuable service in the self-sustaining community we might envision for the future.

Mushroom production is labor- and management-intensive. Specialty mushrooms are not a "get rich quick" enterprise. On the contrary, it takes a considerable amount of knowledge, research, planning, and capital investment to set up a production system. You must also be prepared to face sporadic fruiting, invasions of "weed" fungi, insect pests, and unreliable market prices.
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Abstrack

The market for mushrooms continues to grow due to interest in their culinary, nutritional, and health benefits. They also show potential for use in waste management. However, as fungi, mushrooms have life cycles very different from those of green plants. The choice of species to raise depends both on the growth media available and on market considerations. Oyster mushrooms, which grow on many substrates, are easiest for a beginner. Shiitake mushrooms already have earned considerable consumer demand. Only two mycorrhizal mushrooms, morels and truffles, have been commercially cultivated. Mushroom cultivation offers benefits to market gardens when it is integrated into the existing production system. A careful analysis of potential markets must be the first step in deciding whether to raise mushrooms to sell. Many information resources are available for further research.
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Fistulina Hepatica

location: North America, Europe
edibility: Choice
fungus colour: Red or redish or pink
normal size: 5-15cm
cap type: Other
stem type: Lateral, rudimentary or absent
flesh: Flesh discolours when cut, bruised or damaged
spore colour: Pink
habitat: Grows on wood

Fistulina hepatica Schaeff. ex Fr. Beefsteak Fungus or Ox Tongue Langue de boeuf, Fistuline hépatique Bracket 8-25cm across, 2-6cm thick, usually single, tongue-shaped or semicircular; upper surface pinkish to orange-red and finally purple-brown; rough with rudimentary pores, especially toward the margin; moist to tacky. Tubes up to 15mm deep; arising free, but adhering in maturity; whitish or yellowish. Pores 3 per mm, circular; whitish at first, bruising reddish brown. Stem none or rudimentary; short, thick, blood red. Flesh thick, succulent; mottled, dark flesh-pink with lighter veining, with bloodlike sap; reminiscent of raw meat. Odor pleasant. Taste sourish. Spores ovoid, smooth, 4.5-6 x 3-4µ. Deposit pinkish salmon. Habitat singly or sometimes several in a cluster on the base of living oaks or chestnuts, also dead hardwood stumps. Frequent; common in the East. Common in Europe and found in North America especially eastern areas. Season July-October. Edible-good. Comment Infected oak timber has a much richer, darker color and is much sought after by furniture makers.