Days to germination: Approximately 3 weeks
Days to harvest: 8 to 10 weeks
Light requirements: No light is best
Water requirements: Keep damp at all times
Soil: Manure, straw or sawdust
Mushrooms are probably not a good choice for a beginner gardener as they can take a bit of expertise to get growing. Though getting a commercial “kit” isn’t necessary, it can be an introduction into growing mushrooms and teach you the basics.
There are many kinds of mushrooms that you grow yourself, including: oyster mushrooms, white button mushrooms and even the rather expensive shiitake mushrooms.
One good feature about mushrooms is that you typically grow them indoors, which can make it a good project for anyone without outside garden space.
Mushrooms are enjoyed either cooked or raw, though some types (like shiitake) have a more appealing texture after they have been cooked. They are an excellent source for an obscure mineral called selenium, as well as potassium and several B vitamins.
Starting from Seed
Mushrooms are a fungus, and do not grow like true plants. So your techniques for mushrooms are going to very different from any other growing you do.
Firstly, mushrooms have no seeds. They have spores which look like dust to the naked eye because each spore is microscopic. While it is possible to purchase loose spores, it’s more common to purchase “spawn”. Mushroom spawn is sort of like buying seedlings, but not quite. When you buy spawn, you get little plugs that have been treated with spores. It’s much easier to handle and work with spawn.
You will also need to get the right growing surface for your mushrooms before you can “plant” them. They don’t grow on soil. Each kind of mushroom has its preferred material for growing. For example, oyster mushrooms grow best on straw, button mushrooms on manure, and shiitake mushrooms do best on either sawdust or actual logs of wood.
You need an organic material that will hold moisture, such as sawdust, aged manure, aged compost, shredded newspapers or straw. You can also grow mushrooms on logs, which may be a bit inconvenient indoors.
Containers and Location
Because of how mushrooms are grown, they will always be grown in containers. Trying to grow mushrooms outside or on any naturally occurring substrate (like an old tree in the yard) is an invitation to wild mushroom species that can contaminate your crop. Considering the number of poisonous mushrooms that exist, there is a real risk to your health if something unexpected decides to grow along with your mushrooms.
So find a place in your home where you can keep your mushrooms in the dark. You’ll need to be able to adjust the temperature as well. A closet or small unused room can work fine. Even an empty kitchen cabinet will work for a small crop. Once you have your material and a location set up, you can start your mushroom.
For containers, you’ll need sturdy boxes or bins that are 8 to 12 inches deep. They should have holes for drainage but your straw or compost shouldn’t ever be wet enough to warrant dripping.
Once you have your materials and a location ready, you can plant your spawn. Fill your containers with substrate, and gently pack it down. Give it a watering. Enough so that it’s thoroughly moist not soaked. The spacing for your mushrooms will depend on the type you are growing. Big shiitake mushrooms will take more room than little button ones. The supplier where you get your spawn should have instructions about spacing.
Heat up your growing material to around 70F. You can either heat the room, or use a heating pad for this. Once it’s thoroughly warmed, put your spawn plugs into the surface of the material. Keep everything warm, and you should start to see that there are fungus filaments spreading from the spawn plug into your growing material. They look like fine strands of cotton. It takes about 3 weeks to get to this point.
After that, you need to bring the temperature down to around 55F. Add a little potting soil around the plugs, and keep everything moist and in the dark. A light layer of plastic over the containers can help keep the moisture in, but don’t seal it up too tightly. They still need air.
Check in about a month, and you should start to see young mushrooms starting to form.
Once the mushrooms have gotten established and have started to grow, there is very little for you to do. Keep your chosen material damp, and maintain an even temperature in your growing room. When you water the “soil”, you need to be gentle about it. A spray bottle works best.
Though mushrooms need darkness and steady temperature, they do also need some fresh air. You can’t close them up in a damp room and just hope for the best. After the mushrooms have started to grow, allow a little ventilation without creating drafts or letting your growing material dry out.
Pests and Diseases
Given the nature of mushrooms, and the fact that you will be growing them indoors, there really isn’t much to worry about in terms of insects or even diseases. Too much moisture, and they can rot. That’s all you need to worry about.
Harvest and Storage
When your mushrooms are full-sized, you can start to harvest. Gently twist the mushroom at the base until it comes loose. Do not pull directly, or you will damage the the fungus fibers growing under the surface. With a gentle picking, you will continue to get new mushrooms growing for several more weeks. They will not keep producing mushrooms forever though. Eventually you will need to replant new spawn once your current batch is exhausted.
The best way to store mushrooms is in the refrigerator, in a loose paper bag. Mushrooms do not store very well beyond that, though they can shrink considerably. Use a dehydrator to dry sliced mushrooms, or a low-set oven. Thin slices may be dried crisp, but most pieces will likely be rubbery in texture rather than hard.
They can also be frozen, but it’s not an ideal preservation method for mushrooms. You really need to either cook them first, or give then a 2-minutes blanch in boiling water. After freezing, mushrooms also have a tendency to get discolored when you thaw them out.
But since you are growing your mushrooms indoors, you can always just have a “garden” of them growing for year-round fresh harvesting.