Mushrooms are nutritious and delicious, whether they’re eaten fresh or made into gravies, sauces or side dishes. Learn how to grow mushrooms indoors and you’ll have a fun DIY project for yourself and your kids. You'll also save money, because gourmet mushrooms can be expensive to buy.
Where to Grow Mushrooms
Successfully growing mushrooms indoors requires a place that’s cool, humid and dark or dimly lit.
- When you’re deciding where to grow mushrooms, consider your basement or a cabinet under your kitchen sink. Use a thermometer to be sure the temperature is in the proper range for mushroom production.
- Common mushrooms grown at home, like white button types, need a temperature range of 55 to 60 degrees Fahrenheit. Cold weather gourmet mushrooms like enokis need a constant temperature of 40 to 50 degrees Fahrenheit. Shiitakes prefer 72 to 78 degrees Fahrenheit and oyster mushrooms need a range of 55 to 65 degrees Fahrenheit.
- If your basement or cabinet is too warm for the variety you choose, try growing mushrooms in the winter instead.
How to Grow Mushrooms
Always start your mushroom growing project with a clean work area and clean hands to help avoid contamination.
- The easiest way to grow mushrooms indoors is with a mushroom-growing kit and supplies. Most mushroom starter kits contain the supplies you’ll need for shiitake or oyster mushroom farming. Oyster mushrooms are the easiest for beginners to grow.
- If you decide to gather your own supplies for growing mushrooms, research the variety you plan to grow before you begin.
- Mushrooms grow from dust-like spores, not seeds. Unlike most plants, they don’t need soil. The spores germinate on organic substrates, which you can think of as a growing medium. The substrate could be straw, wood chips, coffee grounds, grain or other organic matter.
- When the spores germinate on the substrate, and tiny, thread-like, white roots appear, the result is called spawn. The tiny roots are called mycelium.
- Some mushroom starter kits come with spawn that’s ready to use. Other kits contain organic matter and spores that you combine to make spawn.
- Mushrooms can grow in spawn, but it's better to apply the spawn to another growing medium, such as a log or a blend of compost with certain nutrients and other kinds of organic matter, such as corncobs or cotton hulls. Ask your local County Extension Service agent for help, or research mushroom compost online, if you want to make your own blend.
- Some cooks and chefs may want to grow different varieties together, but you can’t do this unless the mushrooms use the same substrate and need the same growing conditions.
More Advice on Growing Mushrooms
Some experts say you should always cook mushrooms before eating them. Follow the manufacturer's directions in your mushroom-growing kit.
- When you're finished with your mushroom growing medium, use it in your garden.
- The straw or wood chips used to grow your mushrooms can be used as garden mulch or added to your compost pile. Just don't use anything that shows signs of insect pests or diseases.
- Growing mushrooms in a dark place helps retain moisture, so the spores can reproduce. The exception is when you’re growing shiitakes on a log. Shiitake mushroom logs should be placed outside. Lean them against something or stack them so they don’t touch the soil. This prevents other fungi in the soil getting into the logs.
Common Mushrooms Grown at Home
Common mushrooms grown indoors include white buttons, shiitakes, portobellos and oyster mushrooms.
- Other types of mushrooms aren’t recommended for indoor mushroom farming. Truffles, for example, have a mutually beneficial relationship with certain kinds of trees.
- Some mushroom farmers, gardeners, cooks and researchers believe medicinal mushrooms can prevent or treat diseases. Shiitake mushrooms are thought to lower cholesterol and white button mushrooms contain large amounts of vitamin B complex. Studies of medicinal mushrooms are on-going.
- Never forage for wild mushrooms unless you are a mushroom expert. Some wild mushrooms are toxic, while others are simply tough or bad-tasting.
Mushroom Growing Kits and Supplies
You can purchase mushroom growing kits with all the materials you need to grow mushrooms at home. If you're a true DIY-er, you can buy the materials you need for mushroom farming. You'll also need a few tools, such as a hammer, a drill and a spray bottle, depending on the varieties you grow.
Successfully Growing Mushrooms in Straw
- Make a few holes in the side of a plastic bucket or a plastic storage bin or tub that has a lid. The holes should be about 3/8-inch wide and spaced 8 inches apart.
- Wash the bucket or bin thoroughly with hot water and antibacterial soap, rinse it and dry it with a clean cloth. Put it aside.
- Next, pasteurize some straw to use as a growing medium. Chop the straw into 2 to 4-inch pieces. Put the straw aside while you wash and rinse a large pot to use on the stove. Use an outdoor cooker instead, if you want to keep humidity and odors out of your home.
- Fill the pot with water, leaving enough room to add the straw without making it overflow. Bring the water to a boil, carefully lower the straw into the pot and let it boil for 15 minutes. This will help prevent or lessen the growth of unwanted organisms.
- Use tongs to remove the straw from the water. Let it drain and spread it out on a clean tarp. Cover it with another clean tarp and let the straw cool completely. This can take an hour or more.
- Mix the moist, cool straw with mushroom spawn, such as sawdust spawn. Pack the straw tightly into your prepared bucket or bin and put the lid on it.
- Put the bucket into another bucket without holes, or wrap the bucket or bin loosely with plastic. Leave it for about a week, so the mycelium can form.
- Uncover the bucket or bin and leave it for another one or two weeks in a dark, damp location.
- The first tiny mushrooms to appear are called pins. They'll double in size every day until they're almost ready to harvest.
- Oyster mushrooms are ready to harvest when their rims point downward and curl over slightly.
- Your substrate may produce another harvest in three or four weeks, although it will be about half the size of the first harvest.
- If you see any signs of contamination, such as mold or spoilage, do not eat the mushrooms. It's vital to keep everything clean and sanitary when you're growing mushrooms.
Successfully Growing Mushrooms on a Log
Unlike mushrooms that need organic matter for growing media, shiitake mushrooms grow on hardwood logs.
- Hardwood logs that have been pre-inoculated with shiitake spores are available. Simply soak them in water overnight and stand them upright or lay them horizontally on top of something to keep them off the ground.
- Keep the logs hydrated and you can harvest every two or three months.
- If you’d rather, cut your own log or have someone cut one for you. The best logs for shiitakes come from oaks or sugar maples.
- Cut the log about three to four feet long and three to six inches across. If possible, use the log within three weeks of cutting.
- For best results, order the shiitake plugs for the log before it's cut, so they’ll arrive before the log begins to age. Some plugs are made of organic matter, such as sawdust mixed with nutrients and shiitake spores, and some are hardwood dowels growing shiitake spawn.
- Drill some holes in the log. Make the holes as big as the plugs and space them about three inches apart. Insert the plugs and cover the holes, along with any other bare spots on the log, with a specialty wax called plug wax or with cheese wax, a clear, paraffin-based food-grade wax.
- Take the log outdoors to a shaded location and lean it against something or stack it on top of bricks or rocks to keep it off the soil. Cover it with burlap.
- Shiitakes need moisture to grow, so water the log regularly and during any dry spells. Watch for insects, slugs and hungry chipmunks or squirrels.
- Small, white bumps will appear in about a week. When they do, remove the burlap and replace it with a lightweight row cover until the mushrooms are ready to harvest. They're ready when you can see gills underneath the caps and the edges of the shiitakes curl down slightly.
- Your mushroom log may produce for up to four or five years. Expect your biggest harvest of shiitakes in the second and third years.
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