Growing Shiitake Mushroom

Shiitake Mushroom can be grown either on natural logs or on artificial logs made of a special combination of oak sawdust, bran, millet and other additives. Most small-scale farmers will want to start with natural logs because they require less environmental control.
Further information on sawdust culture can be obtained from Professor Dan J. Royse, at Pennsylvania State University (211 Buckout Laboratory, Penn State University, University Park, PA 16802).

There are five basic steps in cultivating shiitake mushroom on logs:

* Ordering good quality culture, which is called spawn or inoculum, so that it will be on hand when needed. The shiitake mushroom that will grow from the log is the fruiting body of the whole fungus. Most of the fungus is a mat of white strands (mycelia) that grow through the log to collect the nutrients necessary for fruiting. The spawn which you will purchase is nothing more than a pure strain of living mycelia, growing either in sawdust or in hardwood dowels. Contact your County Extension Agent for help in locating a spawn supplier near you.

* Obtaining suitable hardwood logs. Usually oak, maple, beech, ironwood, chestnut or alder are used. The logs are cut green during the winter when the sap is down and are cut to 3- or 4-foot lengths for easy handling. Diameters from 2 to 6 inches seem to work well. Be careful to avoid damaging the bark. Torn bark can allow other organisms to enter the log and compete with the shiitake for nutrients.

* Inoculating the logs. Inoculate the logs with the spawn between 1 and 3 weeks after cutting to ensure optimal moisture content. Inoculate the log by drilling holes partway into the log. Then carefully packed these holes with the spawn and seal them with wax to retain moisture and keep out competing organisms.

* Allowing shiitake to colonize the wood. Once the mushroom has been introduced to the log via inoculation it takes 4 - 9 months, depending upon climate, for the mycelia to spread throughout the log. During this "spawn run" period, the logs are stacked and shaded to avoid moisture loss.

* Inducing fruiting. To induce fruiting the logs are soaked then shaded to keep the moisture level up until fruiting begins. Yields are quite variable. In some cases the spawn will not run through the log and no mushrooms will be produced. The highest yields are only attainable when all conditions are near ideal. The logs can be refruited several times without additional inoculation and can produce mushrooms for several years depending upon how often they are fruited.

There are several additional steps that must be pursued by an entrepreneur to bring the shiitake crop to the market and ultimate sale. Crop harvesting, packaging, storing, transporting, and marketing are some of the vital and important steps that are necessary. However, there are a host of different procedures practiced because factors such as the growers location, time limitations, financial considerations, etc. necessarily dictate the technique pursued.
Information Sources

Several books are available that can provide additional details on growing shiitake. Among them are: