Mushrooms are fascinating organisms that can provide many benefits for humans, such as food, medicine, and environmental remediation. Growing your own mushrooms can be a rewarding and enjoyable hobby, as well as a potential source of income. In this blog post, we will share with you some of the basic principles and methods of mushroom cultivation, and how you can get started with your own mushroom project.
The Life Cycle of Mushrooms
Before we dive into the details of mushroom cultivation, let’s first understand the life cycle of mushrooms. Mushrooms are the fruiting bodies of fungi, which are composed of microscopic filaments called hyphae. The hyphae form a network called mycelium, which is the vegetative part of the fungus that grows on a substrate (a material that provides nutrients and support for the fungus). The mycelium can remain dormant or active for a long time, depending on the environmental conditions.
When the mycelium senses favourable conditions, such as moisture, temperature, light, and oxygen, it produces primordia, which are small bumps that develop into mushrooms. The mushrooms produce spores, which are tiny reproductive cells that can be dispersed by wind, water, animals, or humans. The spores germinate and grow into new hyphae, completing the life cycle.
The life cycle of mushrooms can be divided into four stages: spore, spawn, substrate, and fruiting. Each stage requires different techniques and conditions to optimize the growth and yield of mushrooms.
Spore Stage
The spore stage is the beginning of mushroom cultivation. Spores are the seeds of mushrooms, but they are very different from plant seeds. Spores are microscopic and have no protective coating or stored food. They are also genetically diverse and unpredictable. Therefore, spores are not usually used directly for mushroom cultivation, unless you want to experiment with new strains or varieties.
Instead, most mushroom cultivators use spawn, which is any material that has been inoculated with mycelium. Spawn can be made from grains (such as rye, wheat, millet, or sorghum), sawdust, wood chips, straw, or cardboard. Spawn can be purchased from reputable suppliers or made at home using sterile techniques.
To make your own spawn from spores, you will need:
- Spore syringe or print: A spore syringe contains a liquid suspension of spores in sterile water. A spore print is a collection of spores on a piece of paper or foil. You can buy spore syringes or prints online or from local mushroom enthusiasts. Make sure to choose spores from a species that you want to grow and that is suitable for your climate and substrate.
- Sterilized grain jars: You will need glass jars with lids that have been filled with grains (such as rye berries) and sterilized in a pressure cooker or autoclave. You can also buy pre-sterilized grain jars online or from local suppliers.
- Glove box or laminar flow hood: You will need a sterile environment to inoculate your grain jars with spores. A glove box is a simple plastic container with holes for your hands and gloves attached to them. A laminar flow hood is a more advanced device that creates a stream of filtered air to prevent contamination.
- Alcohol lamp or lighter: You will need a flame source to sterilize your needle before inoculation.
- Alcohol wipes: You will need alcohol wipes to clean your jar lids before inoculation.
To inoculate your grain jars with spores, follow these steps:
- Shake your spore syringe well to distribute the spores evenly in the liquid.
- Wipe your jar lid with an alcohol wipe and let it dry.
- Flame your needle until it glows red and let it cool slightly.
- Insert your needle through the hole in the lid and inject about 1 ml of spore solution into the jar.
- Repeat for each jar using a fresh needle or flaming it between each use.
- Label your jars with the date and strain name.
- Store your jars in a dark place at room temperature (about 20–25°C) for 2–4 weeks until you see white mycelium growing throughout the grains.
Spawn Stage
The spawn stage is when you multiply your mycelium to prepare for substrate inoculation. Spawn can be used as it is or expanded to produce more spawn using the same or different materials. For example, you can use grain spawn to inoculate more grains, sawdust, wood chips, or straw.
Substrate Stage
The substrate stage is when you prepare and inoculate your substrate with spawn. A substrate is any material that provides nutrients and support for the mycelium to grow and produce mushrooms. Different types of mushrooms prefer different types of substrates, depending on their natural habitats and nutritional needs. Some common substrates for mushroom cultivation are:
- Straw: Straw is a cheap and widely available substrate that can be used to grow many types of mushrooms, such as oyster, shiitake, king oyster, and enoki. Straw is high in cellulose and lignin, which are complex carbohydrates that fungi can digest. Straw also has a loose structure that allows for good air exchange and water retention. However, straw also contains many contaminants and competitors, such as bacteria and molds, that can inhibit mushroom growth. Therefore, straw needs to be pasteurized or sterilized before inoculation. This can be done by soaking the straw in hot water (65–80°C) for 30–60 minutes, or by steaming it in a pressure cooker or autoclave for 90 minutes at 15 psi.
- Sawdust: Sawdust is another cheap and widely available substrate that can be used to grow many types of mushrooms, such as shiitake, oyster, lion’s mane, reishi, and maitake. Sawdust is high in lignin and cellulose, which are complex carbohydrates that fungi can digest. Sawdust also has a fine structure that allows for good colonization and fruiting. However, sawdust also contains many contaminants and competitors, such as bacteria and molds, that can inhibit mushroom growth. Therefore, sawdust needs to be sterilized before inoculation. This can be done by loading the sawdust into filter patch bags or glass jars with lids that have holes covered with micropore tape or polyfill. The bags or jars are then steamed in a pressure cooker or autoclave for 90 minutes at 15 psi.
- Wood chips: Wood chips are a natural and sustainable substrate that can be used to grow many types of mushrooms, such as shiitake, oyster, lion’s mane, reishi, and maitake. Wood chips are high in lignin and cellulose, which are complex carbohydrates that fungi can digest. Wood chips also have a coarse structure that allows for good air exchange and water retention. However, wood chips also contain many contaminants and competitors, such as bacteria and molds, that can inhibit mushroom growth. Therefore, wood chips need to be pasteurized or sterilized before inoculation. This can be done by soaking the wood chips in hot water (65–80°C) for 30–60 minutes, or by steaming them in a pressure cooker or autoclave for 90 minutes at 15 psi.
- Coffee grounds: Coffee grounds are a waste product that can be recycled as a substrate to grow some types of mushrooms, such as oyster and shiitake. Coffee grounds are high in nitrogen and cellulose, which are nutrients that fungi can use. Coffee grounds also have a fine structure that allows for good colonization and fruiting. However, coffee grounds also contain many contaminants and competitors, such as bacteria and molds, that can inhibit mushroom growth. Therefore, coffee grounds need to be pasteurized or sterilized before inoculation. This can be done by baking the coffee grounds in an oven at 160°C for 60 minutes, or by microwaving them for 10 minutes on high power.
To inoculate your substrate with spawn, follow these steps:
- Break up your spawn into small pieces using your hands or a clean knife.
- Mix your spawn with your substrate in a clean bucket or container using a ratio of 1:10 to 1:5 (spawn to substrate).
- Fill your growing container with the spawn-substrate mixture. You can use plastic bags with holes punched in them (grow bags), plastic buckets with holes drilled in them (grow buckets), wooden boxes with holes drilled in them (grow boxes), or any other suitable container.
- Seal your growing container with tape or a lid to prevent contamination.
- Label your growing container with the date and strain name.
- Store your growing container in a dark place at room temperature (about 20–25°C) for 2–4 weeks
