Revised November, 2021.
Although over 2,000 varieties of mushrooms are edible, only a handful have become important in the American diet. The mushrooms most familiar to U.S. buyers are the "whites," or common button agaricus. Other varieties of agaricus, the criminis and portabellas, are known as the “browns.” Shiitake (shee tah kay), oyster, wood ear and enoki (e nok e) mushrooms are also popular. Particularly in the Pacific Northwest and the northeastern United States, seasonal species such as morels, oysters and chanterelles are gathered in the wild and sold at farmers' markets and through retail stores. U.S. consumers continue to purchase fresh, canned and dried mushrooms, both domestic and imported. The per capita consumption of fresh mushrooms was 3 pounds in 2015.
The United States produced 844 billion pounds of mushrooms in 2019. The total value of the crop was $1.1 billion in 2019. The number of commercial mushroom growers was 347, a decrease of 11 growers from the previous season. (NASS)
Most commercially produced mushrooms are agaricus species. During the 2020 season, the sale of agaricus mushrooms totaled $1.09 billion. Of the 796 million pounds of agaricus produced that season, the majority, or 824 million pounds, were grown for the fresh market and 55.6 million pounds were processed. (NASS)
Pennsylvania is the leading state producing agaricus mushrooms. The state supplies 66 percent of the nation’s production, with California second at 14 percent of U.S. production. The farms that produced Pennsylvania's large crop of mushrooms in 2020 are concentrated in the southeastern portion of the state. (NASS)
Specialty mushrooms, include shiitake, oyster and similar unusual mushrooms. Sales for commercially grown specialty mushrooms in 2019-2020 were $67.4 million, up 2 percent from the previous season. The average price received by growers is $3.37 per pound, down 7 cents form previous season estimate. A specialty grower is defined as having at least 200 natural wood logs in production of some commercial indoor growing area, and $200 or more in sales. (NASS)
Certified Organic Agaricus and Special Mushrooms
Growers produced 127 million pounds of mushrooms that were certified organic during the 2019-2020 growing season.62 percent of the total 79.4 million pounds, were sold as certified organic mushrooms. Agaricus mushrooms accounted for 88 percent of the mushrooms sold as certified organic and specialty were the remainder. (NASS)
Most hobbyists or small-scale growers should begin by cultivating such easy-to-produce specialty mushrooms as shiitakes and oyster mushrooms. The criminis and other agarics that are commercially grown by large-scale operations are labor- and technology-intensive species, and it is not cost effective to try to compete with large-scale production systems. Likewise, some of the other high-value species (morels, truffles) also are very labor or technology intensive.
Small-scale mushroom production represents an opportunity for farmers interested in an additional enterprise and is a specialty option for farmers without much land. Many small-scale production systems are well suited to market gardeners who wish to incorporate mushrooms into their vegetable production systems and for those individuals interested in using mushroom cultivation as a way to add value from the material derived from thinning woodlots and similar “waste” materials. Mushroom production can play an important role in managing farm organic wastes, encouraging the production of value-added bedding materials from agricultural and food processing by-products.
All commercial mushroom production involves the purchase or production of substrate (bedding-compost) material. This is an intensive aspect of production for large-scale producers; however, it can be quite manageable for small-scale producers and hobbyists. The substrate or compost must be “spawned” with mushroom mycelium that must then be allowed to develop in the compost mixture. This usually is done under relatively aseptic conditions. At some point, after the mycelium has fully colonized the substrate, the “cast” is exposed to air, and perhaps soil and water, to promote formation of marketable fruiting bodies.
Many hobbyist kits and other small-scale production systems use a similar strategy to produce spawn under relatively aseptic conditions. In these systems, the spawn is mixed into a sawdust-based substrate watered and stimulated to fruit. For other species like the oyster mushrooms, the substrate is chopped wheat straw or cottonseed hulls or some mixture of the two, but production is similar. Many kit manufacturers and supply houses market “ready for production” pre-spawned sealed bags of spawned substrate. This, in itself, has become a value-added business for many specialty mushroom growers.
Most U.S. specialty growers use some sort of “synthetic log” production system. Sawdust is the most popular ingredient used in synthetic substrate formulations for shiitake and many other high-value species. Sometimes sawdust is substituted for straw or corncobs. Usually a starch-based supplement, wheat bran, rice bran, millet, rye, corn and so on, is added at a 10 percent to 40 percent dry weight ratio. The starch-based material serves as an additional nutrient source for optimum growth. Many small-scale production systems are simple and inexpensive to establish, with information and materials being readily available from on-line sources and mail order suppliers.
Additionally, there are numerous spawn suppliers throughout the United States and Canada. Besides experimenting with different strains, commercial growers are encouraged to purchase spawn from more than one spawn supplier. Mixing inoculum and spawn sources ensures that different strains can be merged to produce the best mushroom under the specific growing conditions of the operation. Individual strains vary from one to the other. In some cases, strain variability may be extreme. In a Minnesota research study, it was demonstrated that an eleven-fold difference in yield existed across several shiitake varieties. Many spawn suppliers also sell equipment and supplies related to mushroom growing; product catalogs are often available from them upon request.
With respect to the log production of shiitakes, many hobbyists as well as commercial producers use locally sourced logs or other wood material. For instance, the hardwood tree family most recommended in the United States for shiitake cultivation is the oak genus of the beech family. All oak trees can be used with the possible exception of live oak. The thicker bark oaks such as white and chestnut oak are often preferred over the thinner bark oaks such as red, scarlet and pin oak. Beech, birch, chestnut, chink-a-pin, alder, maple, cottonwood, willow, aspen, poplar, elm and hop-hornbeam also may be suitable. As a rule, the thin-bark, low-density species provide relatively quick mushroom production but only for a short time period. Locust, walnut and all conifers are not suitable for shiitake cultivation.
In Ireland, mushroom production is a rapidly expanding new segment of agricultural production that builds on the greenhouse-production model. These new Irish mushroom farms are family-managed units where the production system consists of three to five “polythene tunnels” similar to U.S. hoop buildings. The Irish industry is based on a satellite grower system, whereby growers are linked into central compost companies that supply spawned compost. These companies then collect, grade and market the finished product. More than 70 percent of growers have contracts with central marketing groups.
Mushroom pastes, pates and creamy sauces are popular in Europe, while mushroom-based snacks, cakes, teas and beverages are often consumed in Asia. Jerky-like meat-flavored snacks, extruded "puffy" snacks, even mushroom jellies and cakes are popular in China. Mushroom wine is common in Korea, as are alcoholic drinks with mushroom extract in Japan. Patented products include mushroom and fish paste, mushroom-flavored coffee and soy sauce flavored with mushroom juice.
Many people are intrigued by mushrooms' nutritional properties in addition to their culinary appeal. Mushrooms are the only edible non-animal source of vitamin D. In addition, mushrooms contain some unsaturated fatty acids and provide several B vitamins. Some even contain significant vitamin C, as well as potassium, phosphorus, calcium and magnesium. Mushrooms contain many essential amino acids; white agaricus mushrooms, for example, contain more protein than kidney beans. Shiitake mushrooms are less nutritious but are still a good source of protein. Some mushrooms could be a viable and economical source of antioxidants in the diet. Numerous mushroom-based products have been marketed to promote weight loss.
Mushrooms have been used to treat or prevent diseases for centuries. Asian traditions maintain that some mushrooms are natural pharmaceuticals and promote good health. Researchers have confirmed that mushrooms contain substances that may reduce the risk of cancer, boost the immune system and reduce the risk of coronary heart disease. Other therapeutic applications of mushrooms include wound-healing covers, antibacterial mushroom extracts and liver function preparations. At its clinical trials Web site, the National Institutes of Health lists studies involving oyster mushrooms, agaricus mushrooms and shiitake mushrooms.
Prices for fresh mushrooms are considerably higher in winter than during the rest of the year. Some growers in temperate regions use greenhouses for winter mushroom production in an attempt to expand into the winter market. In many of the greenhouse production systems, water-soaked logs or flats of wood waste are inoculated with spawn and allowed to decompose and fruit. Following the first harvest, the logs are allowed to continue to incubate (up to three months), and the process is repeated (usually up to five times).
Some parts of the country support mushroom-marketing cooperatives. These groups may be an important asset for developing a new business and may purchase wild-harvested mushrooms and those grown by hobbyists and small commercial producers.
Marketing of specialty mushrooms in the United States is a relatively new enterprise. For most individuals, growing shiitake mushrooms will be easier than selling them. Many growers invest time and money in production and devote little effort toward marketing. Even though shiitake is becoming more popular throughout the United States, growers must be excellent marketers as well as producers to succeed financially.
In recent years, the trend for specialty mushroom sales has been toward the retail market. This trend is driven partly by an increased interest in specialty mushrooms and by the convenience packaged products offered to the consumer. In some retail markets, only 10 percent of the customers buy 90 percent of the specialty types.
Global Agricultural Trade System, Foreign Agricultural Service, USDA.
Mushrooms, National Agricultural Statistics Service, USDA.