Hello mushroom lovers! I’m excited to share this super easy method of creating your own mushroom kit, which I stumbled upon very recently. I’d been toying with the idea of growing my own mushrooms as a little science experiment for the kid and as another gardening project. I almost bought a $36 mushroom kit at Sky Nursery the other day, but I’m glad I didn’t! Just two days later, I attended a Hands-On Skills Fair organized by Sustainable NE Seattle and got to make my own mushroom growing kit for free! The other 20 participants and I were guided in this project by Milton Tam of the Puget Sound Mycological Society (PSMS). Check out the gallery of pics above as well as the following directions for building the mushroom kit.

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Here are a few caveats before I lay it out. Mr. Tam developed this easy technique to be used with groups. Any group of kids at a school or summer camp could do this on a picnic table after a trip to Petco and an online order of mushroom spawn or a few previously used kits which now contain mushroom spawn. His emphasis was on making kit instructions out of materials that would be easy to procure, simple to prepare, and not so messy to use. In the Sustainable NE Seattle workshop, people asked all kinds of questions about what post-consumer products they could use instead of buying stuff at Petco. It is possible to make a substrate out of coffee grinds and/or shredded newspaper. The Fungi Perfecti reference booklet mentioned below has professional instructions on that.

DIY Mushroom Kit Supply List:

4 cups of Purina Yesterday’s News recycled newspaper pellets, unscented, no artificial fragrances, softer texture (violet color on package) (one big bag of this product will make 20-22 mushroom kits)

4 cups dechlorinated tap or well water (use warm water or water that has sat out overnight uncovered so chlorine could dissipate)

1/2 cup alfalfa pellets (guinea pig or rabbit food, such as these organic ones) This is optional but improves “vigor and yield of mushrooms and allows for a second fruiting 2 weeks after the first,” according to Tam.

1 cup oyster mushroom grain spawn (or sawdust spawn) from a reputable supplier. 5 lb. bags of just the spawn are $20 from Far West Fungi, CA. NW Mycological Consultants sell 7 lbs. of grain spawn for $20, which will make 22-24 kits. Alternatively, you can break up a kit that you previously made with this recipe that has finished producing mushrooms. Here are two lists of other potential suppliers of spawn.

a large, clean plastic bin for mixing

plastic newspaper bags. These are the right size and shape and have not been treated with anti-microbials as some other plastic bags are.

DIY Mushroom Kit Instructions:

Part 1: At the workshop:

Combine the newspaper pellets and water in the plastic mixing bin and let them sit for 5-10 minutes until they absorb all the water (no pooling) Mix the soaked mixture to fluff it up a little, then add the alfalfa pellets (optional) and 1 cup grain spawn. Mix well, then fill the newspaper bag with this mixture (you’ll have to use your hands – make sure they’re clean) Pack down gently to remove air pockets, then twist and tie a knot at the end.

Part 2: At home:

Cut 4 slits about 1″ long in the plastic bag. Place kit in a dimly lit or dark, cool area (60-70 degrees F). Mark with the date. After 2.5-4 weeks, the bag should be filled with white mycelium. At this point, move the mushroom kit to a cool, well-lit room but keep it out of direct sunlight (not on a windowsill). Inspect daily for signs of baby mushrooms (primordia) growing at slits or elsewhere. Cut more holes in the bag if necessary to free the growing mushrooms. Use boiled and cooled water (or water that has stood out overnight) to mist mushrooms several times a day, as evaporation stimulates growth, but do not soak or over-wet. Mushrooms should double in size every day. Pick whole clusters when each mushroom is about 2″ in diameter. Cook in your favorite mushroom dish and enjoy! Once this first fruiting is over, you can return the kit to a cool, dark place for another 2-3 weeks and repeat the whole process a second time. Once you are done with the kit, you can break it up and use 1 cup of the material as the “mushroom spawn” ingredient for a new kit (so maybe make 5 new kits out of one spent one?), or break up and add to your garden soil or compost pile as a soil amendment.

Right now I’m at step 3. I hid the kit in a cabinet so dark and neglected that I found all kinds of canning equipment in there that I had thought was lost or had been given away. Yay! When I checked it 2.5 weeks later, it was firm and full of white stuff. I snapped that picture of it on some leaves outside, then brought it in, where I’ve been looking it over and googling what primordia look like. I also need to find a little spray bottle for misting. Stay tuned for updates on how my mushrooms turn out. I’m thinking gomba paprikás or mushroom quiche when they’re fully grown. Fingers crossed!

Update: This yielded 3 cups of oyster mushrooms and I did make gomba paprikás! Check out this follow-up post for the recipe and some additional tips!