Shiitake mushrooms are one of many edible forms of fungi grown commercially today. Their use can be found mainly in restaurants, farm markets or health food specialty stores. Shiitake mushrooms have been a part of Oriental diets for centuries and as such became a natural product for farming. There are two methods of farming shiitake mushrooms; mushrooms can be grown on logs or in forms molded from sawdust. There are advantages and disadvantages to both types.
Log grown shiitake mushrooms are grown on hardwood logs cut and soaked in water. Sawdust shiitake mushrooms are grown in logs molded from sawdust and grains. The log growing method takes substantially more room because of the logs. Using sawdust methods, growers can use shelving systems and racks which provide greater use of space. Log grown mushrooms are prone to humidity and temperature variations in the weather and in the logs. Sawdust grown mushrooms can be grown in controlled environments where the humidity and temperature can be monitored and maintained easier.
Log growing methods started in China over 900 years ago whereas sawdust growing methods have only been in use since the 1970s. Log growing spread to the US as popularity for the shiitake mushroom spread in the later half of the 20th century. While many US mushroom farms still use log growing methods most Chinese and Japanese farms use the sawdust growing method.
Log grown mushrooms can only be harvested naturally in Spring and Autumn; they can also be forced into production up to two more times. Sawdust grown mushrooms can be grown year-round because they are not prone to climate and weather.
Growing shiitake mushrooms on logs is labor intensive whereas sawdust grown mushrooms can be picked quickly by hand or machine. Daily harvesting is required for log grown mushrooms. Once a log has "dried out" it can no longer be used for production. Sawdust logs can be formed when needed. Mushroom strains used with logs can take months to years to produce a crop. Mushrooms in sawdust can be harvested within weeks cutting the harvest time by months.
Log grown shiitake mushrooms are considered higher in value and quality than sawdust grown shiitake mushrooms. The value can be from two to eight times higher for log grown mushrooms. Log grown mushrooms, according to a 2002 study by Brauer et al., are almost twice as high in health and medicinal value than mushrooms grown in sawdust. Capital investment for sawdust mushroom farming is higher than for log mushroom farming.