Mushrooms have no chlorophyll and do not use sunlight or the process of photosynthesis to make their own food. Most of these fleshy, spore-bearing fungi are saprophytes, which means they derive their food from dead or decaying matter, but some are parasites, which feed on living hosts.
Mushrooms appear outdoors naturally from spring to late autumn, but because some of the wild ones are highly poisonous, it is essential to learn from an expert before attempting to harvest them.
Fortunately, there are a few cultivated types, such as shiitake, that do not pose the danger of wild ones and that can be started indoors from kits sold in catalogs, at garden centers, and over the Internet.
Commercial button mushrooms require complete darkness, but most of the gourmet mushrooms grown indoors need some indirect light, says Paul Stamets, author of Growing Gourmet and Medicinal Mushrooms. Regarding how much light is enough, Mr. Stamets says, “If there’s sufficient light to read the instructions on a mushroom kit, there’s enough light to grow them.”
The growing medium of choice is wood or straw, which must be kept evenly moist. Air temperatures typically range between 50º and 80ºF. With a bit of luck, mushrooms from kits will appear in about two weeks.
Watching the process can be a lot of fun, and most kits will yield a small crop, but growing your own is not a way to save money on mushrooms. If you plan to eat them often, you’ll still be buying most of your supply.