Because mushrooms don’t contain chlorophyll, cultivating them is a little different from what’s required for green plants. The fastest and easiest method is to buy an indoor grow block or kit—usually about $30.
Kits are available for a limited variety of mushrooms, sold individually because each type needs a specially formulated growing medium, called a substrate. But no matter which species you order, indoor growing requirements are basically the same.
The blocks—which weigh about 3.5 kilograms and are a compact 15 by 22 centimetres—need to be placed in a humid area (somewhere between 80 and 95 per cent relative humidity) with a temperature range between 12 and 20˚C; so avoid the main part of your home or greenhouse.
“The average house is usually too dry in winter,” says Bill Wylie, president of Wylie Mycologicals in Wiarton, Ontario, “while greenhouses get too much light and tend to be too warm in spring and summer.” Instead, he recommends a damp basement or garage. Since mushrooms grow naturally in wooded areas, he suggests people mimic those conditions by giving the fungi dappled light for part of the day. Strong, direct light can produce deformed specimens.
Also, avoid watering. “If you water, you risk introducing bacteria and contaminating the block,” explains Wylie. Instead, maintain constant levels of humidity in the room. If that’s a problem, boost the moisture level with occasional misting, or tent a plastic dry cleaner’s bag punched with holes over the kit—just make sure the plastic doesn’t touch the grow block.
A few days after starting, dot-sized growths will form on the surface of the block; a week later, you’ll be harvesting mushrooms. An average block, which yields more than one harvest, will produce about one kilogram in total.
Mushrooms can also be grown outside in the garden. “They’re incredibly beautiful and highly underrated garden plants,” says Roseanne Van Ee, an interpretive naturalist who runs fall mushroom “safaris” through Outdoor Discoveries in Vernon, B.C. “There’s a whole range that people can introduce to the garden and enjoy as accent plants or prized edibles.” But be patient; it may take a year or more for mushrooms to fruit.
It’s also possible to order mushroom spawn (ready-to-grow fungal spores—sometimes included with a soil medium and manure—used as a starter) or logs plugged with spawn to place in the garden. As a rule, spawn is best spread in spring, but when to spread it or lay logs and how to care for outdoor mushrooms depends on region and microclimate.
The logs must remain undisturbed while the spawn grows, which can take up to two years. When ordering them, ask if the logs are ready to fruit or whether they need a period of rest.
If they are ready for fruiting, you can “shock” the logs by soaking them in cold water for 48 hours before putting them in the garden (in 60 to 80 per cent shade). Or put the logs out dry and let nature do the work. Wet, warm spring weather is usually enough to encourage fruiting; light watering may be necessary, however, during prolonged dry spells.
Outdoor growing, though, isn’t for everyone. “You’re faced with lots of contaminant problems and animals—insects, slugs, deer—and you’re always fighting the elements,” says Wylie.
In that sense at least, growing mushrooms is like gambling on anything else in the garden—only with a bit of luck, this gamble may pay off in delicious dividends.