Commercial kits for growing mushrooms often are expensive for what you get. Usually, all they contain is a tray or other container, growing medium, and inoculant, which is material that has the mushroom spores in it. There is usually also an instruction pamphlet, but since growing mushrooms is easy, this is normally not very extensive. To my way of thinking, it isn’t worth spending $25 or more for this when you can make your own cheaply.
To make your own, you’ll need a tray that is at least 6-8 inches deep. You’ll also need high-nitrogen manure that isn’t too hot. Horse manure works well as does cow manure that has been mixed with finished compost, so it doesn’t generate so much heat that the developing mushrooms are killed.
Finally, you’ll need a dozen or so raw button mushrooms.
Put the manure in the tray. It should be broken up so it isn’t in clumps. You can wear gloves to do this but don’t be afraid or squeamish about the manure. It is what the mushrooms you’ve been eating were grown in.
Dampen the manure. It should be damp but not wet. The level of the manure should also be an inch or two below the rim of the tray.
You are then ready to make your inoculant and spread it. To do this, leave the button mushrooms you purchased at the store at room temperature for a few days to allow the caps to open and the spores to mature.
When the caps are open and the gills on the underside look dark brown or black, put the caps in a blender and add just enough water to blend them; perhaps a cup or so of water. Blend the mushrooms and water for a half-minute to a minute to make a dark slurry. This is your inoculant. Pour this over the manure.
Cover the tray and put it in a dark, warm place for one to three weeks. The bed should be kept around 70° F (21° C) and it should be checked daily to make sure that it is kept damp. As necessary, use a mister to lightly mist the top of the bed.
When you see a network of what looks like fine white hairs growing over the top of the bed, you are almost there. The network is the mycelium of the mushrooms. Cover the mycelium with an inch or so of damp potting soil or damp peat moss.
At this point the bed needs to be kept at a lower temperature; about 55° F (12° C) Again, keep the bed moist. It can be helpful to cover it with plastic wrap to retain the moisture.
In about a month, you should start seeing mushrooms popping up. The longer they are allowed to grow before harvesting, the larger they get if they have room to grow. They can be harvested by cutting them off close to the level of the dirt or gently twisting them out of the soil.
Take care with this part because there is still mycelium growing under that layer of soil and you don’t want to damage the mycelium. In fact, when you harvest some of the mushrooms, cover that area with more damp potting soil/peat moss and more mushrooms should be produced there.
The inoculant you made contains thousands of spores, so if the bed is kept cool and damp, the bed should produce mushrooms for up to 6 months.
The total cost of all of this should only be about $2-3, particularly if you buy the container tray from a dollar store. It could cost even less if you bought some fresh button mushrooms at the store and they start getting old before you have the chance to use them. Simply use them to make the inoculant.
Do you think you might try doing this sometime?
It sounds interesting so I might try it if I have the chance