Mushroom cultivation is an intricate, but rewarding art. The fungal networks called mycelium need specific conditions to produce healthy mushrooms. If the conditions are off, the mycelium will be too busy fighting microbes to produce healthy fruiting mushrooms. For the beginner, I recommend a mushroom growing kit. These kits come with a pasteurized substrate, grain spawn, and a suitable container for cultivation. These kits provide novice growers the opportunity to go through the steps of growing mushrooms with little risk of contamination. The resourceful and bold can gather and pasteurize their own substrate, although I would recommend buying mushroom spawn for first timers. The cultivation of spawn is a time consuming process. In this article, I will cover how to grow mushroom on substrate. Mushrooms can also be grow on logs, but that will not be covered in this article. I will also demonstrate mycological applications beyond growing edible and medicinal mushrooms.
Growing from Mushroom Kit:
Substrate: Sawdust, straw
Sturdy plastic bags or burlap sack
70% alcohol solution
five cups of potable water
tea leaves/coffee grounds(optional)
How to inoculate mushrooms with a kit:
1.Clean the preparation area, try to minimize noise and air flow to prevent dust particles blowing around. Wipe hands with alcohol solution to sterilize.
2. Place substrate in bag and add water and less than of a cup of hydrogen peroxide. If you are using sawdust pellets, break them down by squeezing the bag or with your sterilized hand.
3.Fresh brewed coffee grounds and tea leaves can be added for additional nitrogen
4.Sterilize the outside of the spawn bag. Break up the grains in the spawn bag, then cut the bag with a sterilized knife. Add spawn to the substrate bag and distribute as evenly as possible.
5. Seal the bag to prevent contaminants; kit bags usually have a filter patch to let air in (1).
Keep the mushroom bag in a cool dark place such as a closet or your basement for about 2 weeks to a month When growing outside, keep it in a well-shaded area. The mushroom can incubate at temperatures between 10℃ to 26℃. However, 15℃ is the optimal temperature for thriving mycelium.
After 2 weeks to a month, structures will begin to appear in the mycelium. These structures are called primordial mounds. They are emerging fruiting bodies of the mushrooms. Cut a slit in the bag around the primordial mounds. Next, cover the growing bag so that it is exposed to light only on the side with the opening. This will focus the growth of mushrooms in one area, which will result in a better harvest. At this point, the growing bag can be taken outside especially if the indoor environment is too dry.
Once the mushrooms are sufficiently big, they can be broken off the block. Mushroom can be dried in the sun for storage or medicinal use. Drying in the sun increases the vitamin D content immensely. However, high humidity that produced great growing conditions, is not ideal for drying. Even in the hot sun, high humidity can lead to rot of the mushrooms. Drying in the oven is recommended for areas where humidity is high.
DIY Substrate and Spawn:
Without a mushroom kit, you must supply your own substrate and spawn. The substrate is a medium on which the mycelium can thrive. These include, but are not limited to; straw, sawdust, compost, paper, cardboard, tea leaves, and coffee grounds. It can also be grown on a wide variety of dead biomass, don’t be afraid to experiment. When choosing a substrate, make sure it is untreated with chemicals as these can accumulate in the mushrooms. Some species of mushrooms grow better on particular substrates, so do your research.
Pasteurization of the substrate is a process to eliminate harmful microbes, giving your spawn a head start to colonize the substrate. The aim is to pasteurize, not to sterilize the substrate. Sterilizing the mushroom gets rid of all bacteria, where as pasteurization mainly destroys harmful bacteria. One of the easiest ways to pasteurize is to boil water, then bring the water to 71-76℃. Add the substrate for about an hour.
Cold incubation is alternative way to give the mycelium a head start. This involves inoculating a substrate without pasteurization, then keeping the substrate at 2 to 10 degrees celsius. This can be done in cold climates by leaving the substrate outside in the spring or the fall. These method works best with cold tolerant mushroom, such as oyster mushrooms.
Spawn is a mass of mycelium that is used to inoculate substrate. Spawn can be purchased cheaply and easily. However if you have a couple months before you want to inoculate, spawn can be created at home. Growing native mushrooms is a valuable practice as they are adapted to the climate and microbes. Find and identify fresh mushrooms and cut the bottoms off, making sure the rhizomorphs stay in tact. The bottom of the mushroom is referred to as stem butts. Then soak some cardboard and split in two, the middle is exposed. Space the stem butts apart in the cardboard and fold and layer cardboard over the top. Soak cardboard with the stem butts in water and store in a container of some sort. After a few months, there will be a significant mycelium mass to inoculate substrates.
Mycorestoration and permaculture applications.
Mushrooms have other uses beyond food and medicinal teas; they are remarkably good at restoring and cleaning the environment. The mycelium build soil by breaking down biomass into nutrients. They help plants grow and degrade harmful chemicals from area.
Mushrooms like King Stropharia (Stropharia rugoso annulata) and the Elm oyster mushroom(Hypsizygus ulmarius) are excellent companions to plants in the garden. King Stropharia nickname is the Garden giant. These saprophytic mushrooms break down organic materials and enrich the soil. They also form a direct symbiotic relationship with the plants themselves. The mycelium feeds of the waste products of the plants, while it’s networks gather and transport nutrients to the plants roots. Paul Stamets experiments show that soils with Elm oyster mushroom can increase brassica plant growth by a magnitude of 4(1). To include mushrooms in your garden, cover the soil around plants with straw or wood chips, then mix spawn with the substrate. The mycelium will take hold and begin to assist the plants. Actual fruiting of the mushrooms, might not happen the first year depending on the species.
Mycofiltration is one of the ways mushrooms can be utilized in a permaculture system. Mycofiltration is the process by which mycelium in the soil filter or digest chemicals passing through. Bags of inoculated substrate are usually installed near water runoff areas to filter out pollutants and chemicals in the water. Turkey Tails(Trametes Versicolor) and Oyster(Pleurotus ostreatus) are two useful mushrooms in mycofiltration. Turkey Tails is known to filter or digest the following pathogens: Aspergillus niger, Candida albicans, Escherichia Coli, Staphylococcus Aureus, and Streptococcus pneumoniae. Oyster mushrooms(Pleurotus ostreatus) can filter or digest Aspergillus niger. Bacillus spp, Escherichia coli, Plasmodium falciparum, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Staphylococcus aureus (2). Oyster mushrooms and turkey tails are able to digest chemical warfare agents, pesticides, preservatives, petroleum hydrocarbons, byproducts of incineration, and TNT. Oyster mushrooms are extremely effective at removing mercury from the environment, it accumulates 140% of the normal levels. Turkey Tail is also able to remove mercury.
Mushroom bags can put in groundwater channels(such as swales and ponds) to remove contaminants from the water. Burlap sacks are recommended over plastic bags for this process. The containers need to be permeable to allow water to pass through. If there is any pollution in the area,these mushrooms would not be safe for eating, . However, the water passing through the substrate will be cleaner and less polluted.
After a period of time, mycelium substrates will stop producing mushrooms. At this point, the Substrate waste is known as Spent Mushroom Substrate(SMS). SMS can used as a fodder for animals and as feedstock for biofuel. The most effective use of SMS is it’s soil enhancing qualities. When SMS is added to soil, it adds organic matter and buffers ph. It slowly releases nutrients and increases the soil nutrient capacity. SMS contains microorganisms that provide disease control and degrade harmful chemicals (3).
1. Instructions for the Grow It Yourself Reishi Mushroom Kit. Hamilton, NY: Imaginary Farmer, 2012. Print.
2. Stamets, Paul. Mycelium Running: How Mushrooms Can Help save the World. Berkeley, CA: Ten Speed, 2005. Print.
3. Suess, Amy, and Jennifer Curtis. Value-added Strategies for Spent Mushroom Substrate (n.d.): n. pag. British Columbia Ministry Of Agriculture And Lands, Aug. 2006. Web. 23 June 2015.