Mushroom Cultivation: A Beginner's Guide To Success

Mushrooms are the fruiting bodies of fungi and can be cultivated both indoors and outdoors. They are packed with nutrition and offer a range of health benefits, including immune system support, brain health, and protection against certain types of cancer. Growing mushrooms at home is easy and can be done using logs or indoor cultivation kits. The process involves introducing mushroom spores or mycelium to a suitable substrate, allowing the mycelium to permeate the substrate, triggering mushroom development through environmental adjustments, and finally, harvesting the mature mushrooms.

Choosing the right substrate

Mushrooms are the fruiting bodies of fungi, thriving on substrates rich in organic material. The substrate in which they grow must provide them with the right mix of nutrients, including sugar, starch, lignin, fats, protein, and nitrogen. There are multiple substrates that can be used for successful growth, ranging from simple to complex. Some mushrooms grow better on a specific substrate, and the ideal conditions for each mushroom will vary.

When choosing a substrate, it is important to consider the specific needs of the mushroom species you are cultivating. Each species has unique requirements, and observing their development is key. Commonly used substrates include growing media such as compost, straw, sawdust, or even coffee grounds. Straw and sawdust should be pasteurized to kill any contaminants. Oyster mushrooms, for example, are known to grow well on hardwood logs.

It is also possible to purchase pre-made mushroom blocks filled with oat bran, sawdust, or other substrate materials already coated with mushroom spores. These blocks should be misted three to four times a day with spring or well water, collected rainwater, or boiled tap water. Tap water should not be used as it contains chlorine that will kill the spores. After each misting, the block should be covered with plastic to hold in the humidity.

For those who wish to create their own mushroom cultures and spawn, a sterile workplace is necessary, along with a means of sterilizing agar and grain. A pressure cooker or autoclave can be used for sterilization. This process is more challenging and is not recommended for beginners.

Providing the right conditions

Mushrooms are the fruiting bodies of fungi, thriving on substrates rich in organic material. They require adequate moisture, proper temperature, and limited light. By replicating their natural habitat, you can successfully cultivate various mushroom species.

The first step in providing the right conditions for mushroom growth is to select the appropriate substrate. The substrate is the material on which the mushrooms will grow and can include compost, straw, sawdust, or even coffee grounds. The substrate must provide the mushrooms with the right mix of nutrients, including sugar, starch, lignin, fats, protein, and nitrogen.

Once you have selected your substrate, it is important to treat it properly. This may include pasteurization, sterilization, lime bath, peroxide bath, or cold fermentation. For example, if you are using straw or sawdust, you may want to pasteurize it to kill off any contaminants.

After treating the substrate, you will need to inoculate it with mushroom spores or mycelium. Mycelium is a thread-like network of fungus that will permeate the substrate fully before mushroom development is triggered through environmental adjustments.

To create the optimal environment for colonization, maintain a temperature of around 70-80°F and a high relative humidity to minimize drying out the substrate or spawn. Keep the environment clean to prevent contamination, and maintain some airflow. You can increase humidity by routinely spraying the substrate with water and covering it with plastic after misting.

Once the mycelium has fully colonized the substrate, you can induce fruiting by controlling temperature, light, humidity, and airflow to match the recommended conditions for your chosen mushroom species. For example, only white button mushrooms need to grow in the dark, while other species can grow in indirect light.

Inoculation and colonisation

Inoculation is a vital step in the process of mushroom cultivation. It involves inserting the mushroom spawn (the mycelium of a mushroom) into a substrate that is suitable for growing. The spawn then colonizes the substrate, eventually leading to the growth of mushrooms. The substrate is the mushroom's food source and can include materials like straw, wood chips, sawdust, coco coir, and coffee grounds. The type of substrate chosen will depend on the type of mushroom being grown. For example, oyster mushrooms are more flexible when it comes to substrates, while other species may require a specific one.

Before inoculation, the substrate must be prepared. This includes ensuring the substrate is clean of contaminants, has optimal moisture content, and is mixed if desired. For outdoor methods, there is little concern for introducing contaminants, while most indoor methods require the substrate to be inoculated in a sterile space. If using grain or sawdust, indoor inoculation is necessary, and a strict procedure must be followed, including wiping surfaces with alcohol and sterilizing tools.

The inoculation rate, or the amount of spawn added to the substrate, impacts the speed of colonisation. A higher inoculation rate will lead to faster mycelium growth through the substrate, but it will also increase costs. For new cultivators, a high inoculation rate can boost the success rate, but as skills improve, the rate can be lowered to reduce expenses. The length of the inoculation process will vary depending on the type of mushroom, the substrate, and the conditions. Generally, it takes a few weeks for the spawn to fully colonize the substrate. After colonisation, with the right conditions (humidity, temperature, light), mushrooms will begin to grow.

There are several methods for spawn distribution during inoculation. Two common techniques are "top spawning" and "through spawning." Top spawning involves placing the spawn on top of the substrate and letting it grow down, which is suitable for inoculating full containers like mason jars. Through spawning involves mixing the spawn into individual bags or drilling holes into logs and stumps. The method chosen will depend on the substrate and the equipment available.

Fruiting and harvesting

Mushrooms like cool, humid conditions, but it is possible to grow them in more arid climates. In commercial practice, watering is typically done 2 to 3 times each week, but the amount of water used depends on the dryness of the casing, the cultivar being grown, and the stage of development. Most first-time growers apply too much water, which can seal the surface of the casing and prevent the exchange of gases essential for mushroom pin formation.

Harvestable mushrooms appear 18 to 21 days after casing. Ideally, mushrooms should be harvested just before the spores are released. The timing of fresh air introduction is very important and is something learned only through experience.

Oyster mushrooms are the easiest species to grow, and they can be grown using the bucket method.

Growing kits and supplies

If you're a beginner, it's best to start with a mushroom-growing kit. Companies like North Spore offer a range of products and kits that provide you with everything you need to simplify the cultivation process.

You can also purchase individual supplies from companies like North Spore, which include:

• Sterilized substrates for growing gourmet edible and medicinal mushrooms, such as grain bags, CVG, hardwood-based Wood Lovr, manure-based Boomr Bag, and the ShroomTek all-in-one grow bag.
• Cultivation containers: monotubs, bags, or outdoor beds, depending on your chosen method.

If you're using a log, you'll need to source the log yourself and drill holes all over it. You'll also need mushroom spawn to put into each hole, and some wax to seal it over. You'll need to keep the log damp—if it doesn't rain at least once a week, you can use a sprinkler to water it.

If you're growing indoors, you'll need a large, clear plastic tub to catch all the spores and keep the humidity high.

Frequently asked questions