Ever wonder where those miraculous morsels called mushrooms come from? Though their technical category of fungus doesn’t exactly entice, button mushrooms, with their smooth and creamy texture and snow white skin, are both beautiful and delicious.
And did you know that you can experience the fine flavors of fungi from the comfort of your own home? Carla Emery shows us how.
Decide where you’re going to grow mushrooms — in a cave or fallout shelter, under the kitchen sink, or whatever. Mushrooms are the only “plant” crop that doesn’t need light to grow, since they make food from manure and other decaying organic material rather than from sunshine. In fact, until the mushroom is actually ready to fruit, its growth is held back by the presence of light. So mushrooms are best grown in a basement, cellar, cave, or mine; in the dark, damp space between the floor of any building you have and the ground under it; or in a windowless building like a garage or barn, as long as it doesn’t get too cold inside.
Commercial growers build special mushroom houses where they keep the temp at 55–65˚F. Your growing place will work best if the temp hovers around 45–60˚F, but the mushrooms won’t die unless they either freeze or get way too hot.
2. In What Containers?
The growing boxes can be heavy, waxed cardboard, but wooden boxes hold up better in the long run. Make your boxes at least 6 to 8 inches deep. You can just spread them out. Or to use space more efficiently, build a shelf arrangement for them. Make the bottom shelf at least 6 inches above the floor. Make the next shelves 2 feet above each other. You can go as high as the ceiling height allows.
3. In What Soil?
Mushroom-growing soil is called “compost,” and that’s basically what it is. Different mushrooms grow best in different soils. Shaggy mane mushrooms like horse manure. Shiitake and Enoke like a sawdust/bran mix.
Buttons and oysters will grow on this mixture:
Start with 4 parts grass or straw. The compost process goes best if you plan to work a 500-lb. lot at a time. Shred the grass or straw (lawn-mowing clippings work too). Wet it with nonchlorinated water, cover, and let soak several days. Now you’re going to make a compost heap. Spread out your straw/grass a few inches high. Spread a layer of fresh cow, horse, or other manure over it. (Mike Hess says, “Horse manure’s the best. Cow and pig are inferior and to be avoided.”) Spray with water and keep adding more layers the same way until you’re out of shreddings and manure. Cover with plastic and let ’er heat! After 5 days, start checking every day to see how the center temp is doing. When the temp starts dropping, turn and circulate the heap, water as needed, cover, and continue composting. You’re done when turning no longer results in an increased temp. You have to let the manure age enough so that it won’t heat up to more than 85˚F, which would harm your mushrooms.
4. Bake the Growing Soil.
This sterilization step is really important; please don’t skip it. (You’ll hear much more about sterilization from Mike later.) Mushrooms have quite a few natural enemies: bugs, worms, molds. This step protects them; it also ensures that you won’t grow any kind of mushroom-toadstool–looking thing except exactly what you intend to. Bake each box, dirt and all, in your oven at 200˚F for at least 1 hour. Let the oven get hot before you start timing the hour. Other ways to accomplish this are to compost the manure mixture beforehand and make sure it gets up to at least 170˚F. After your soil has cooled down to no more than 70˚F, make sure it’s loose and not hardpacked.
If the compost is so dry that it doesn’t feel moist to the touch, spray before planting.
5. Load Growing Boxes.
Put your growing mix into the boxes 6 to 10 inches deep. Don’t pack it tightly. Smooth the top with a fork.
6. Plant the Spawn.
Dried spawn keeps a long time in a cool and dry place, but spawn that is moist must be refrigerated or planted right away. Sprinkle spawn over the surface. Then sprinkle more pasteurized manure-compost mixture a couple inches deep over that; work the spawn flakes with your hands gently into the soil mixture; or lift some soil, spread the spawn with a teaspoon, and then replace the soil over it. Make these plantings about 8 inches apart.
7. Maintain Humidity and Dampness.
Now sprinkle with lukewarm water and plan on keeping the mixture wet. It works best if you water with as fine a spray as you can manage. Check often enough to make sure the mushroom bed doesn’t dry out, because if you let it completely dry out, that could be the end of your hoped-for mushroom crop. For a single, small box, it helps at first to put a damp cloth over the tray. Or rig up some constantly dripping water to keep humidity high in your mushroom-growing area. On the other hand, you can drown your mushrooms with too much water. If you can squeeze some of the growing mixture in your hand and no water comes out, it’s still on the okay side. A plastic tent over your growing boxes helps hold in humidity without keeping the dirt itself oversoaked.
8. Do Casing.
About 4 weeks after you plant your spawn in the boxes, your mushroom crop is ready to . . . “flower”? . . . “fruit”? . . . grow mushrooms. For, believe it or not, the mushroom you eat is a sort of flower. Or maybe it’s more of a fruit.
The mushroom, in the form of that mycelium, does most of its early growing below ground, where the food is. It doesn’t create the part of the plant that you think of as a proper mushroom until conditions trigger its reproductive phase. There has to be enough of a mycelium, which then builds and feeds the mushroom. When mycelia — silky white threads that look like cotton — have grown out from each of your planting sites until they almost meet, it’s casing time. You may even already see the first sign of life from your mushrooms above ground — a small knob growing above ground from that mycelium underneath. Mike Hess: “If the mushroom forms a ‘knob’ above ground before casing, then casing is probably unnecessary. But no knob will form, generally, until after you case. That’s what casing is for.”
Casing works because it’s a layer of soil that’s not sterilized and, for some unknown reason, the introduction of vigorous microscopic critters atop your mycelium growth at this stage triggers fruiting! So casing encourages the mycelium to make an aboveground mushroom flower/fruit.
Here’s how to do it:
Sprinkle on anywhere from 1⁄2 to 1 inch of screened clay loam (or plain loam, but not sand and not soil with any partly rotted composting material in it).
During the fruiting stage, the plants need some fresh air. Don’t overdo it to the point of drafts, but have enough air circulation so that the natural metabolic gases can’t accumulate. At the same time, the mushroom growing place needs to have a temp as nearly steady as possible in the 50–60˚F range.
About a week or 10 days after the casing, you’ll see mushrooms starting to form. Ten days after that, you’ll be able to start picking. Harvest every day. Pick them just before they open out. When you pick, twist to prevent pulling up lots of “root,” which would cause damage to the mycelium. Water as needed, just enough so the growing soil stays damp. But if you see spotted mushrooms, that means you need more ventilation and much less water. Your beds will now continue to grow mushrooms for about 3 to 6 more months, as long as the good temperature conditions hold and bugs and other competition stay out.
11. Raise Your Own Spawn.
A box where mushrooms have been grown for several months has what is called “running spawn” all through it, at the level where you first planted spawn. You can use that dirt (unpasteurized, of course) to plant other boxes. If you dry the dirt in an airy but shaded place, you can store it under dry, dark, cool (but above freezing) conditions for maybe up to 10 years. Or the used box of soil will be a good addition to your garden or potted plants.