Maitake mushrooms are grown in Japan and the Northeastern United States, originating from the roots of old trees, particularly oak trees. They are sometimes grown by mushroom cultivators in these areas, but are not sold widely in the United States as of 2015, and are primarily found in supplement stores.
Mushroom cultivators may grow maitake mushrooms, but they do not tend to grow as large as wild specimens. Some of these mushrooms found in the United States have weighed up to 50 pounds, and those that harvest these mushrooms can fill their cars up to capacity and still leave plenty of maitake in the forest.
Maitake mushrooms can be grown anywhere with the right artificial conditions. Cultivators typically use artificial logs made of sawdust and fillers, such as bran, in order to feed the growing mushrooms. These mushrooms are first spawned on the log for 30 days. The mushroom-covered logs are then placed in a special controlled-environment room where the humidity, temperature and airflow can be carefully regulated. Once small mushrooms begin growing on the log visibly, the log is moved to another room with conditions that are engineered to allow the mushrooms to grow quickly and easily. Maitake mushrooms can only be harvested once after being grown. The process goes from lab to the harvest and consumption in about 10 to 14 weeks.