Indoor Gardening: Edible Mushrooms

Venturing into the world of indoor mushroom growing can be intimidating at first. Spawn, substrate and sterilization aren’t the traditional jargon employed by tomato, spinach and cucumber growers. But don’t let a few new vocabulary words overwhelm you. In reality, mushrooms are relatively easy to produce at home without a significant investment of time, money or space. They don’t require expensive grow lights or fertilizers and they are relatively low maintenance.

The first, and perhaps most difficult step, is simply choosing which variety to grow. There are many types of mushrooms that can be grown indoors, including button, oyster, shiitake, and portobello. Each variety has its own environmental requirements, so it’s important to choose the right one for your space and skill level. For the novice mycologist, oyster mushrooms are generally a comfortable entry point. They’re easy to grow with minimal effort.

Once you have chosen your mushroom variety, it’s time to gather needed supplies. This is where the new lingo comes into play. You’ll need spawn (the “seeds” of the mushroom) for your chosen variety, substrate (the material for the mushrooms to grow on), a container with a lid, a spray bottle, drill with a small bit and alcohol (for sterilization). Typical substrates or primarily comprised of straw or sawdust from hardwoods such as maple, beech or ironwood. This is the medium where the mushroom’s mycelium will establish itself, gather moisture and feed on the carbon held within the material.

Plastic tubs or mushroom grow bags act as suitable containers. For our oyster mushroom example, I’d recommend starting with a plastic tub and hardwood sawdust substrate. Drill small holes all around the sides and lid of the tub to allow for proper ventilation. Then, sterilize the container and lid with alcohol.

Before placing your substrate into the container, it will first need to be sterilized or pasteurized. This ensures that your mushrooms are pure and eliminates the risk of unwanted mold, fungi or bacteria taking hold. Mix your hardwood sawdust substrate with water in a large pot until it is moist but not soaked. Bring the mixture to a boil before letting it cool to room temperature. With the substrate prepared, pour it into your container and thoroughly mix in your spawn. A ratio of 5-10% spawn-to-substrate would be ideal for oyster mushrooms.

JASON MISPAGEL Indoor Gardener

Now, seal the container with the lid and let it incubate for several weeks in a warm, dark place (68F to 75F). During this time, the spawn will grow and colonize the substrate.

Initially, small white mycelium spots will form on the sawdust. Once they’ve covered the substrate in its entirety, it’s ready for fruiting (the period when edible mushrooms will form). Remove the lid from the container and move it to a location with indirect light (i.e., a windowsill or spare room with a light on) and high humidity. Mushrooms don’t use light to photosynthesize like plants do, so their needs are very minimal. Instead, light is the trigger for them to begin fruiting.

Mist the substrate with water several times a day to keep it moist and, within a few days, you should begin to see mushrooms growing out of the substrate. Once the oyster caps are open but have not become flat, carefully pick them from the substrate by twisting at their base. They’re ready to eat! Continue misting the substrate, even after harvesting, to encourage new mushroom growth.

Hopefully your first fruitful harvest will provide the inspiration to dig a little deeper into mycology and all the various substrate combinations, mushroom types and growing methodologies. Happy growing!