Cultivating mushrooms no easy task

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Humans are still moving, raggedly, from hunter-gatherer to farmer. Some of the organisms we eat, exploit or befriend - grains, trees, cattle, dogs - tamed readily. Kingdoms other than plant or animal are less tractable. Fungi have come under our rule only grudgingly and rarely.

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The familiar button mushroom (Agaricus bisporus) has been cultivated for 300 years. But the most prized mushrooms are still hunted in the wildlands where they volunteer to grow; given the odd patterns of growth and the acute toxicity of some of them, the stakes are high.

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Taming mushrooms is a challenge because we're dealing with a huge, mostly invisible organism whose behavior we've barely begun to understand. What we see and eat is only the fruiting body of the fungus; most of its works - the mycelia - live underground, or in the leaf-litter layer of a forest, or inside the wood of a dead or live tree.

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Imagine trying to cultivate a tree when all you can see is its fruit, and you never know which acre of your orchard it will show up in.

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There are mushroom farms, such as Far West Fungi in Moss Landing (Monterey County), where founder John Garrone and his family grow several edible varieties.

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And there are fungus aficionados such as Ken Litchfield, whose mushroom cultivation course is being offered this fall at Oakland's Merritt College (see Resources). Litchfield and his students are trying to induce some of the wild-card mushrooms to behave more predictably.

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Under live oaks and madrones at the edge of the Merritt campus, Litchfield has set up mushroom beds with excelsior, wood chips and straw.

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"It's like a little hobbit village out here," he jokes. The largest structure is a straw-bale igloo; mushrooms will grow out of the straw in its humid interior.

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Mushrooms, Litchfield says, make their living in several ways: as symbiotes, linked to oaks and other trees; as parasites on living plants; or by decomposing dead organic matter. Some species can be either parasitic or symbiotic; others switch from one strategy to another during their life cycles.

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Opportunists
"Morels are opportunists," he explains. "That's the one that everyone wants to grow. They're not that hard to grow, but getting them to fruit predictably is a problem." Morels pop up after wildland fires; Litchfield suspects their growth is stimulated by smoke. This fall his class will make its own smoke extract and apply it experimentally to a morel pit.

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As chanterelles do with oaks, Litchfield and his students have a symbiosis with Far West. The farm uses blocks of compressed oak sawdust, inoculated with spores. The Merritt classes get the blocks, waning in productivity, that Far West is ready to recycle. Techniques that work in Merritt's experiments are passed along to the farm.

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Home mushroom-growing kits have been around for a while. Far West's Kiera Ilusorio says the shiitake kit is the biggest seller for home growers at the store in San Francisco's Ferry Building Marketplace: "They're a little easier. Tree oysters take more attention."

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Each kit comes with growing instructions. "You're trying to re-create the forest floor," she says.

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Finesse required
Ilusorio cautions that a certain amount of finesse is required. "People get the kits as gifts and don't know what to do with them. The hardest thing to hear is: 'It grew a black fuzzy lump I thought was mold, so I cut it off,' " she says.

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"The kits are like an amaryllis bulb," Litchfield says. "They fruit and then they're done. But after the first flush, you can transplant the kit into a bed of wood chips."

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Then it can go on producing and, with luck, inoculate the entire bed with mycelia. Outdoor beds need protection from snails and slugs, but mold is less a problem than for indoor growers.

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In other symbiotic relationships, Litchfield is working with Merritt's permaculture program to grow huitlacoche on corn, and has produced oyster mushrooms in worm boxes. His students also spend time in the lab and the kitchen.
"I've always used the mushrooms as an excuse to cook," he says.

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Resources

Ken Litchfield's mushroom class begins today, with late enrollment through Sept. 5. Go to peralta.edu and click on Enroll Now. For class schedule and course description, go to merrittlandhort.com.

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Far West Fungi, No. 34, Ferry Building Marketplace (Market at Embarcadero), San Francisco. (415) 989-9090 or store. farwestfungi.com.

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E-mail comments to home@sfchronicle.com. -SFGate