Watch your crops mushrooming

ERIC MUELLER of Mueller’s Mushrooms says you can expand a commercial oyster mushroom kit into two or three kits to grow at home:

What you’ll need

• Oyster mushroom “kit” (mixture of mycelium and some substrate — i.e., growing medium — like straw) sold by various producers

• Disposable gloves (for handling mushroom spawn and mixing)

• Clear or translucent plastic tub, at least 54 quarts

• Spray bottle with weak bleach mixture (a tablespoon of bleach mixed with a quart of water)

• Paper towels (to dry the tub)

• Presterilized 10-pound ice bags (available online or at Smart & Final stores)

• Twist ties to close your bags (may come with the bags)

• Big sack (about 20 pounds) of fresh coffee grounds, preferably used and discarded that day

• Pushpin thumbtack for quickly making air holes in the bags

• Spray bottle of water for misting your kits

1

Assemble your materials. The longer your spawn is exposed to air, the more likely it will become contaminated with bacteria, which compete with mushrooms for nutrients. Move as quickly as you can to get the spawn mixed with your substrate — here, coffee grounds — and packaged.

2

Don your gloves. The gloves will protect your hands and the mixture from any possible contaminants.

3

Clean your tub and gloves with bleach solution. Use paper towels to dry the tub and your gloved hands.

4

Start mixing. Pour the coffee grounds into the sterilized tub and, working quickly, start mixing the mushroom spawn into the coffee grounds, adding a few handfuls of spawn at a time.

5

Pack the bags with the mixture quickly. Start adding the well-mixed coffee grounds and mushroom spawn into the ice bags, packing the contents firmly into the bag. We filled about 2¾ bags with the mixture.

6

Tie the bags closed and poke in air holes. When the bags are full, push out as much air as

you can and then twist the tops closed, securing them with twist ties. Then using the pushpin, poke holes up and down the bag. Mueller poked about four or five holes in a line on each of the bag’s four sides.

7

Find a place to keep your kits and don’t move them. If conditions are right, Mueller said, the mycelium should start fruiting (i.e., making mushrooms) in a couple weeks. The right conditions include filtered light, humidity, a comfortable temperature (in the 60s or 70s) and air flow. It’s best to store your kits in a translucent tub — put the tub over the top of the kits without a lid, or cut a hole in the tub and stuff it with “teddy bear guts” (polyester fiber) so air can get in without contaminants. Once you create your kits, the less you move them the faster they’ll fruit.

8

Slice a few holes once the kits start turning white. If you see white moldy stuff appearing in the coffee grounds, rejoice! That means the mycelium is growing. Use a razor blade or very sharp knife to carefully cut two to four slices in the plastic so the mushrooms will be able to emerge. The more cuts you make, the smaller your mushrooms will be, Mueller said, so go easy. Replace the tub, make sure it stays hydrated and wait for the mushrooms to emerge.

9

Harvest when the tops flatten out but the edges are still slightly curled. Wait much later and the mushrooms will form spores. They’re still OK to eat, Mueller said, but they get messy.

Alternate method: Use an empty gallon water jug. If you're a regular coffee drinker, you can try a more modest technique, slowly filling an empty gallon water jug with a handful of the mushroom kit and then that day's coffee grounds, storing the kit in a clean, cool place each day until the jug is full.

Mueller suggests cutting three-quarters of the way around the top of the jug, so the top hinges back and you can easily reach inside.

Add a handful of the mushroom kit to the bottom with your cooled coffee grounds, then close the jug with plastic wrap (to keep out contaminants) until you add mycelium mix and grounds the next day.

Keep the unused mushroom kit in a clean, cool location between fillings, and when the jug is full, close the hinged top with waterproof tape and unscrew the lid of the jug, so air can get inside (you can also use your pushpin to poke a few holes in the plastic).

Cover the jug with your translucent tub (you can put the jug on its side), misting occasionally to keep humidity high. Once the mycelium starts to grow, remove the screw top so the mushrooms can grow out the top. It’s an easy way to create successive plantings too.

Final tip: Think good thoughts

about your mushrooms, but don’t fret over them, Mueller said. “Sing them songs about squirrels ... or whatever,” he said, laughing. “Think about them a lot, but don’t overthink this, because everything has an effect, and belief and intent are powerful things.”