Shiitake Mushrooms

Grow Shiitake Mushrooms

Anyone can grow these great-tasting and good-for-you fungi.

Leah Zerbe April 14, 2015

Shiitake mushrooms have long been used medicinally in Asia. Some studies have found the fungi to hold antitumor properties. But many shiitake mushrooms you'll find at the supermarket are grown in sawdust, not on logs, leaving them with fewer nutrients. And shiitakes grown in the sun can have much higher doses of vitamin D. While log-grown shiitakes go for up to $40 a pound in Japan, you can enjoy their superior flavor and increase your nutrient intake by growing your own at home.

Rusty Orner, owner of Quiet Creek Herb Farm and School of Country Living with his wife, Claire, shared his mushroom expertise at the Pennsylvania Association for Sustainable Agriculture's 19th Annual Farming for the Future conference. While most participants in the room were farmers, serious gardeners, and/or sustainable-food advocates, the truth is growing shiitake mushrooms in your yard isn't very difficult. Here's how:

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Find Your Logs
You can use logs or branches from freshly cut, living hardwood trees (white, red, or pin oak, sugar maple, or ironwood). It's best to cut between October and April when the moisture content is ideal. Logs should be three to eight inches in diameter. You can also find suitable logs from timber stand improvement cuts. Cut the wood into three- to five-foot sections. Once finished, you should be able to grow mushrooms from one log for five to nine years.

Select Your Spawn
To grow shiitake mushrooms, you need to make a one-time investment in spawn, the fungus tissue used to propagate mushrooms. Ornel trusts family-owned Field & Forest Products. Spawn comes in different forms, including wooden dowels called plugs, as well as sawdust and grain mixes, but plugs are easiest for beginners. It's best to inoculate your cut logs within two weeks of cutting to prevent fungal infection, so time your cutting according to your weather.

Drill Diamonds
Once the temperature in your area is consistently above freezing at night, it's time to drill holes into the wood. The plugs should come with instructions indicating what size drill bit to use. "You want to drill, inoculate, and seal all in one day," explains Joe Krawczyk, owner of Field & Forest Products.

Keeping a two-inch margin at the top and bottom of the log, drill holes in a diamond pattern, with the top and bottom of the diamond six to eight inches apart and the diamond's sides about an inch apart. You can make as many diamonds as will fit on the log. Fill the holes with your plugs according to the instructions, and seal with wax. Many plug kits include their own wax, but cheesewax or beeswax, warmed until it just turns soft, will work. Avoid paraffin waxes: they are laced with toxic chemicals.

Stack 'Em Up
Take your inoculated logs outside and lean them in an area that receives half sun and half shade. Ornel says propping them under white pine trees is a perfect environment. Expect the fruit to pop out 8 to 16 months after inoculating. Check frequently as the fruiting time approaches. Once they pop, the window of opportunity for harvesting the mushrooms is only about a week. If everything goes as planned, each log could produce one to one and a half pounds of mushrooms twice a year.

Give 'Em A Thump
You can induce production after the first year by thumping your logs in the spring, summer, or fall. "I've been doing this 30 years, and it works," says Krawczyk. Simply pick up the vertical log and let it slide down so the bottom slams into the ground. This movement, particularly if done when rain is in the forecast, is said to spur growth. Lore also has it that doing this causes thunder, so be careful.

Pick Only The Right Mushrooms
It's important to be sure of what you're harvesting off your log, since some mushrooms are poisonus. The good news is most poisonous mushrooms don't grow on logs, and shiitakes have a distinctive look: Their main characteristics are a white stem with gills that are not directly attached to the stem. "The gills should be tightly packed," explains Krawczyk, "and the mushroom cap brown to black, depending on humidity." You also want to make sure the mushrooms you harvest are sprouting from your inoculation sites, not elsewhere on the log. If you're still not sure, invest in a good mushroom guide with color photos to make sure what you're picking is a shiitake.

Eat Fresh Or Dry
Mycologist Paul Stamets  has done some interesting research showing that mushrooms left to dry in the sun have a lot more vitamin D, a vital daily nutrient. The mushrooms take about two days to dry, but the method may yield mushrooms with signficantly higher nutrients. You can store them in a glass jar in a dark place for up to a year, says Ornel. To revive a dried shiitake, soak it in water for 30 minutes, or add the dried mushrooms to soups.