Rather than getting rid of that old pair of jeans or composting those spent coffee grounds, consider using them to grow mushrooms instead. Mycologist Tradd Cotter has been researching innovative mushroom cultivation practices for more than 20 years. In his new book, Organic Mushroom Farming and Mycoremediation , he takes “organic” one step further by introducing an entirely new way of thinking—one that looks at the potential to grow mushrooms on just about anything, just about anywhere, and by anyone. In the following excerpt, Cotter explores how to grow oyster mushrooms using recycled materials.
Buy this book from Chelsea Green: Organic Mushroom Farming and Mycoremediation
Use Recycled Materials to Grow Oyster Mushrooms
In the United States, an average of 35 percent of home waste and 60 percent of business waste is suitable for use as a mushroom growing substrate. Mushrooms can be grown on toilet and paper towel rolls, egg cartons, newspapers, magazines, coffee grounds, tea bags, old cotton clothing, tissue boxes, shredded paper, cardboard boxes, and many other common materials. In addition to yielding a bountiful mushroom harvest, these products can also be used to expand myce- lium into a biomass that could conceivably be used to inoculate larger waste streams or substrates for a wide spectrum of applications, including composting, mycoremediation projects, and creating value-added consumer goods such as insulation.
To recycle and compost with mushrooms, start by simply identifying your biodegradable waste. Separate your weekly garbage for a few weeks to de- termine exactly how much waste of each type—paper, cardboard, glass, plastics, food—you are generating. (This will also help you determine where you can improve consumer packaging decisions, reducing your plastic and Styrofoam purchases as you shift to packaging that can be put to better use with mushrooms.)
Open your cupboards, look in your refrigerator, and peek in your cellar for anything you are consistently producing as waste. Check with local businesses about the waste they pay to get rid of, and you may be surprised to find them willing to let you cart off some of their trash. Dumpsters and other sites where debris is often piled up on street corners or behind restaurants and businesses are also great areas for collecting recyclable debris. Smaller companies that cannot afford or don’t have the space for a recycling dumpster often just flatten boxes and stack them up for trash removal; those boxes can be gold for a mushroom cultivation operation.
I try to think of treating my home and life like a “space bubble,” attempting to minimize the nonrecyclable goods I bring in, pretending that landfills do not exist. Thinking this way involves a shift in consciousness where you start to look at everything available in terms of its potential to be recycled and its potential as a cultivation resource. Here are a couple of my favorite mushroom composting and recycling projects.
Cultivating Mushrooms on Clothing
I started growing mushrooms on clothes when I first became interested in mycoremediation of waste dyes and pigments. There was a textile mill near our farm that manufactured denim for the production of jeans and other clothing. My wife Olga and I went to the mill one day and were greeted by a few friendly folks. I told them I was interested in remediating the indigo carmine they were allowed to release into the waterway based on EPA daily allowable standards. They looked at me a bit nervously, as if I were a whistle-blowing undercover environmentalist; picking up on that, I quickly told them about my mycoremediation research and passions. The man I was speaking to happened to be the owner, and he was excited to hear about the prospect of lessening the mill’s environmental impact. The following week I decided to grow mushrooms on old jeans to see if they could decolorize the indigo carmine that makes them blue.
My first experiment was a success, with oyster mushrooms colonizing and fruiting very well on old cotton jeans, but the decolorization of the indigo carmine that I expected was not evident. Turkey tail mushrooms and a few other species are more efficient at the decolorization process, but what I learned is that old cotton clothing can support fruiting oyster mushrooms. (This could be potentially valuable survival information for anyone directly impacted by a natural disaster, where there is a huge amount of debris, but food is scarce.) Old cotton shirts, bits of rugs, hemp and sisal rope—any material composed of natural plant fibers, including cotton, hemp, and bamboo, can be used to cultivate mushrooms. It only needs water and a bit of oyster mushroom mycelium to get started.
Step-By-Step Cultivation on Clothing
Step 1. Soak the clothing in fresh water. The water does not have to be sterile or clean, only free of heavy metals.
Step 2. Flatten the clothing on a surface. Sprinkle the mushroom starter culture over the surface sparingly. Remember, more spawn will speed the process, not necessarily produce more mushrooms.
Step 3. Roll the clothing tightly, or if you have more than one article of clothing, stack it in spawned layers. Place the clothing in a plastic bag or an enclosed container with a few holes.
Step 4. Check the moisture content of the clothing every few days during colonization to make sure the fabric does not dry out; mist or water it as needed. Room temperature or cooler is perfectly fine for colonizing clothing scraps.
Step 5. When the entire mass of clothing seems to have been completely colonized by the mycelium, increase ventilation by adding more holes or cracking the lid of the container, but not enough that the clothing will quickly dry out. Keep the surfaces misted slightly to induce mushroom formation. The colonization process can vary from one to two weeks depending on how much spawn you use. At this point the mushrooms are not interested in fruiting so no light is needed to promote primordia formation.
Step 6. Once mushrooms begin to appear, which can occur a few days to weeks after colonization depending on temperatures and spawn amount used, they will double in size every day. Mist as frequently as needed to keep the mushrooms from drying out at a young state. When the mushrooms stop growing, they are ready to harvest.
Cultivating Oyster Mushrooms on Spent Coffee Grounds
Cultivating oyster mushrooms on spent coffee grounds is a simple and enjoyable home activity for all ages, resulting in some good edible mushrooms to boot. If your home brewing doesn’t provide enough grounds, try asking your local coffee shop or roaster if you can leave a bucket for them to toss their grounds into, especially if they would otherwise go into the trash. If you’re not able to inoculate your grounds with spawn right away, freeze them until you’re ready to do so; otherwise molds will form within days.
Although the yields you’ll get from this method are not as high as when you use commercial oyster mushroom formulas, such as pasteurized wheat straw or cotton waste, if you factor in the production costs, the lower-yield coffee grounds method becomes as economically viable as the more sophisticated cultivation.
If you simply recycle your own grounds you can expect to produce a few pounds of beautiful oyster mushrooms a week—at which point you’ll need to create an oyster mushroom dressing, sautéing your harvest in a balsamic vinaigrette and tossing it over fresh greens crumbled with feta cheese. (Please note: although I have primarily used this process for cultivating oyster mushrooms, some European growers have successfully fruited parasols from coffee grounds.)
Step-by-Step Cultivation on Coffee Grounds
To begin, you’ll need a container with a lid, a steady supply of coffee grounds (with or without paper filters), and grain- or sawdust-based oyster mushroom spawn.
Step 1. Carefully collect the cooled and spent coffee filter, grounds and all, and place it into the container faceup. If using a press or strainer just add the grounds to your container once they are drained well.
Step 2. Massage your mushroom spawn bag to separate the grain or sawdust into individual bits to maximize the spreading capability.
Step 3. Sprinkle the mushroom spawn sparingly over the surface of the coffee grounds. You only need a small amount. Crack the container lid so it can breathe. The container can be located anywhere, such as a kitchen counter, garage, or any other space where there is indirect light, never direct sun.
Step 4. Add coffee grounds and filters daily, sprinkling spawn sparingly over each layer as you add more. After just a few days, mycelium will start to be visible as white threads growing together.
Step 5. Fill the container almost to the top, leaving just a few inches of space to make room for developing mushrooms. When you stop adding filters and coffee, the mycelium will finish colonizing.
Step 6. Once the container is completely colonized, expose it to diffuse natural or fluorescent light at room temperature. (If it gets direct sunlight the mycelium and mushrooms will dry up and you won’t get a harvest!) Keep the surface misted lightly and the lid just cracked, to preserve moisture. If you have filled a 5-gallon bucket or similar large container, you can drill 1/2-inch holes around the sides, every 10 inches or so, where the mushrooms can also emerge, but you will need to either mist the holes several times a day indoors or cover the container with a large, clear bag to make a humidity tent until the primordia have safely emerged and are no longer at risk of drying out.
Step 7. Two to three weeks after the colonization is complete, mushrooms should begin to form. Remember that mushrooms only form when they run out of food or space, at which point they recharge their battery and fruit. Baby mushrooms will appear overnight, so check your buckets at least once a day and keep the surface misted, though not underwater. The mushrooms should double in size every day. Harvest them when the fruitbodies’ growth slows. You may notice a powdery spore deposit forming underneath the caps when they are ready to harvest.
Step 8. After you’ve harvested the mushrooms, allow the mycelium to rest by not watering or adding any additional growing media, and it may fruit again in a few weeks. During the rest period no light is needed if you need to move the container. Soaking the coffee grounds with a generous amount of water after a few weeks of resting can help shock the mycelium into fruiting more prolifically. Once rehydrated, the biomass will respond with additional fruitings.
Step 9. After the second flush, your coffee grounds substrate will be pretty much spent as a mushroom growing medium. However, being full of fungal life, it has now become a living compost starter and can be mixed into your outdoor compost pile to help with the decomposition, or you can use it to inoculate cardboard cultures. Worms also love this spent media, so adding the grounds to your vermicomposting bin could possibly start a worm revolution.
Buy this book from Chelsea Green: Organic Mushroom Farming and Mycoremediation.