FUNGUS AMONG US: GROWING GOURMET SHIITAKE MUSHROOMS

There are fungus among us, and many of them are easy to grow organically and taste delicious.  Shiitake mushrooms, Lentinula edodes, are well known for their anti-cancer, antibacterial and antiviral properties, and also show promise in lowering blood pressure and cholesterol.  A 100 gram serving  of Shiitake contains approximately 33 grams of protein, 29 grams of dietary fiber, 11.6 mg of vitamin C, 23 mg of calcium and is an exceptional producer of vitamin D with 110 IU.  Shiitake mushrooms impart a mild garlic flavor, and enhance a wide variety of culinary dishes, from soups to stir-fries.   First cultivated in China during the Sung Dynasty (960-1127 AD), Shiitake have gained in popularity ever since.  The ancient technique for Shiitake cultivation included selecting hardwood logs already harboring the mushroom, and then vigorously beating the logs with wooden clubs in order to mash mushroom spore into tree bark.  Once beaten, the logs were buried beneath soil for a year and watered until mushrooms appeared.   Results from this method were inconsistent, and depended on logs already bearing the mushroom. Centuries of Shiitake cultivation have greatly improved the technique, and now anyone can easily grow and enjoy an abundance of delectable and healthful Shiitake mushrooms with a few simple tools and materials.
 
Recent development in mushroom cultivation utilizes fresh cut oak, beech or chestnut logs approximately 4  long and 6  wide. Logs for Shiitake cultivation are cut in the autumn following leaf drop, but before winter when sap flow ceases.  Once logs have been cut, Shiitake spawn must be introduced into the logs immediately, to provide the Shiitake a head start over other competing fungi.  Mushroom spawn, which is similar to the vegetative part of a plant which can be reproduced by cuttings or divisions, is grown on either wooden plugs or a grain and sawdust mixture.  Plug spawn consists of wooden dowels thoroughly permeated by Shiitake mycelium, a fungal network of thread-like cells, and are easier to use than sawdust spawn because they do not require specialized tools for inoculation.  Shiitake plug spawn, as well as other edible and medicinal mushroom spawn, can be acquired by mail order through either www.fungiperfecti.com or www.mushroompeople.com. Once logs have been selected, 5/16  diameter holes are drilled 1  deep every 6  along the log in a uniform pattern until the entire bark surface is covered in alternating rows.  Inoculated plugs should fit drilled holes snuggly, and one or two blows with a hammer will place the top of the plug just below the surface of the bark.  Clean hands are important during this process so as to prevent contamination of the plugs.  Melted cheese wax or paraffin should be used to seal holes once plugs are hammered in, and can be painted on with a 1 -2  clean paint brush.  Sealing inoculated holes helps to maintain high humidity and reduce insect and microbial damage to the spawn.  
 
During incubation, logs require shade, good air movement and access to water if rains are not dependable.   Logs should be watered  for one hour twice per month during dry seasons in order to maintain adequate moisture to sustain mycelium growth.  Logs can be set just above ground level on blocks during incubation, or if numerous logs are inoculated, they can be stacked to replicate the cabin-style, with horizontal layers of logs.  Covering logs with a tarp or shade cloth will aid colonization and prevent humidity fluctuations. There are a numerous signs indicating Shiitake mushroom progression through the logs.  White colored mycelium will appear on the ends of logs in star-shaped patterns after 6-24 months.  Also, a pleasing sweet to slightly astringent aroma will begin to permeate from the logs once they are fully saturated with Shiitake mycelium.  Mushroom flushes will typically occur during spring or fall when ambient moisture level is at its highest.  Mushrooms will be ready to harvest when caps are approximately 2 - 4  wide.   A sharp knife or scissors should be used to cut mushroom stems close to the base of the log, and should never be torn from logs to reduce exposing areas where insect pests or mold could become established. Shiitake mushrooms can be eaten fresh, frozen, cooked or dried and stored for later use.   
 
An often overlooked attribute of Shiitake mushroom cultivation is their ability to enhance a shade landscape setting.  The mushrooms are very attractive when fruiting, and can add a unique and functional element to the garden.  Logs will continue to produce mushroom flushes for 4-8 years, depending on log size and growing conditions.  Shiitakes have few natural predators once established, so deer and rabbit damage is not a concern.  For those interested in edible mushroom cultivation, I recommend both books written by Paul Stamets, Mycelium Running and Growing Gourmet and Medicinal Mushrooms.  Marvin’s Organic Gardens has been growing organic edible mushrooms for over a decade and would be glad to answer any questions you might have throughout the process.  Please contact Wes Duren for comments or inquiries regarding mushroom cultivation.