Mushrooms are one of the most intriguing and rewarding foods to grow at home, but they are also very different from conventional plants. Unlike vegetables and flowers that grow from seeds, mushrooms are the fruiting bodies of fungi and are cultivated in a unique way. Growing mushrooms is less about planting a seed in soil and more about creating the right environment for fungal growth. This makes the process fascinating for gardeners and food enthusiasts who want to explore a new challenge. Understanding the biology of mushrooms, the growing conditions required and the practical steps involved is key to success.
Understanding mushrooms and fungi
Before learning how to plant mushrooms, it helps to understand what they are. Mushrooms are the reproductive structures of fungi, similar to how apples are the fruit of apple trees. The main body of the fungus, known as mycelium, is a network of fine filaments called hyphae that grow through organic material such as soil, compost, straw or wood. When conditions are right, the mycelium produces mushrooms, which release spores to spread and reproduce. Unlike plants, mushrooms do not rely on photosynthesis, so light plays a much smaller role in their growth compared to other crops.
Mushroom spores and spawn
Mushrooms reproduce via spores rather than seeds. These spores are microscopic and difficult to handle directly for home growers. Instead, mushroom cultivation typically begins with spawn, which is a carrier material such as grain or sawdust that has been inoculated with mycelium. This spawn acts as the equivalent of seed for mushroom growing. By planting spawn into a suitable growing medium, gardeners introduce mycelium that will colonise the substrate and eventually produce mushrooms.
Choosing mushroom varieties
There are many types of mushrooms that can be grown at home, each with its own requirements. Common button mushrooms and chestnut mushrooms are often grown on composted manure. Oyster mushrooms are more versatile and can be grown on straw, cardboard or wood chips. Shiitake mushrooms typically grow on hardwood logs. Each variety has different flavours, textures and cultivation methods. For beginners, oyster mushrooms are often recommended because they are fast growing and forgiving, while button mushrooms are popular for their familiarity. Choosing the right variety depends on taste, space and the materials available.
Preparing the growing medium
Mushrooms require a substrate rich in organic matter for the mycelium to feed on. The preparation of this medium varies by variety. For button mushrooms, composted manure is the traditional choice, providing the nutrients needed for growth. For oyster mushrooms, straw is often chopped, soaked and pasteurised to kill competing organisms. For shiitake mushrooms, freshly cut hardwood logs are used, as the mycelium feeds on the wood over several months. Preparing the substrate correctly is one of the most important steps, as contamination from other fungi or bacteria can ruin a crop.
Planting mushroom spawn
Planting mushrooms involves mixing the spawn into the prepared growing medium. For compost based mushrooms, the spawn is scattered and mixed evenly into the compost. For straw based systems, the straw is layered with spawn in containers or bags. For logs, holes are drilled and filled with spawn, which is then sealed with wax to prevent drying out. Once the spawn has been introduced, the mycelium begins to spread throughout the medium, a process known as colonisation. This stage usually takes several weeks and requires warm, humid conditions.
Conditions for colonisation
During colonisation, mushrooms need steady warmth and moisture but not light. A temperature of around 20 to 24 degrees Celsius is ideal for most species. The growing medium should be kept damp but not waterlogged, as too much water can suffocate the mycelium. Containers can be covered with breathable lids or placed in dark areas to create the right environment. Over time, white threads of mycelium spread through the substrate, and once it is fully colonised, the fungus is ready to produce mushrooms.
Initiating mushroom growth
To encourage mushrooms to form, conditions must be altered to mimic the natural triggers fungi experience in the wild. For many mushrooms, this involves lowering the temperature and increasing humidity. For example, oyster mushrooms will begin fruiting when exposed to cooler air and higher levels of moisture. Button mushrooms require a layer of casing soil spread over the colonised compost to help trigger fruiting. Light can also play a role, not for energy but as a signal that it is time to fruit. Providing gentle indirect light is often enough to encourage mushroom development.
Maintaining humidity and air flow
One of the most important aspects of mushroom growing is maintaining high humidity. Mushrooms are composed largely of water, and without enough moisture, they dry out and fail to form properly. Misting the growing area or using a humidity tent helps keep conditions ideal. At the same time, mushrooms require fresh air, as carbon dioxide build up can cause long, thin stems and poor caps. Balancing humidity and ventilation is crucial for healthy crops. Gardeners often achieve this by providing regular air exchange while ensuring moisture levels remain high.
Harvesting mushrooms
Mushrooms grow rapidly once they begin fruiting, often doubling in size within a day or two. Harvesting should be done when the caps are well formed but before they flatten and release spores. This is usually when the caps are still slightly curved underneath. Mushrooms are best picked by gently twisting and pulling them from the substrate rather than cutting, as this reduces the chance of contamination. After harvesting, the mycelium may rest for a short period before producing another flush of mushrooms. Depending on the variety and conditions, several flushes can be harvested from a single batch of spawn.
Storing and using mushrooms
Freshly harvested mushrooms are best eaten quickly, as they deteriorate faster than most vegetables. They can be stored in the fridge for up to a week in paper bags, which help absorb moisture and prevent sliminess. Some varieties, like oyster mushrooms, dry well and can be rehydrated later, while others, such as button mushrooms, are best eaten fresh. Home grown mushrooms have a distinct flavour and texture, often superior to supermarket varieties, making the effort worthwhile.
Growing mushrooms indoors
Mushrooms are often grown indoors because it is easier to control conditions of warmth, humidity and light. Spare rooms, basements, sheds and even cupboards can be used if the environment is kept suitable. Indoor cultivation also reduces the risk of contamination from other fungi. Mushroom growing kits are available for beginners, providing pre prepared substrates and spawn, making the process simpler. These kits can be an excellent way to learn before moving on to more advanced methods with raw materials.
Growing mushrooms outdoors
Certain mushrooms can be grown outdoors, particularly those suited to logs, such as shiitake. In this method, logs are inoculated with spawn and left in shady, damp areas of the garden. The mycelium gradually colonises the wood over several months, and mushrooms emerge when conditions are right. Outdoor cultivation is slower but requires less maintenance, as the environment provides much of the necessary humidity and ventilation naturally. This method appeals to those who enjoy a low effort, long term project with rewarding results.
Challenges of mushroom cultivation
Growing mushrooms comes with challenges that differ from conventional gardening. Contamination is a constant risk, as moulds and bacteria compete with mushroom mycelium. Careful preparation and hygiene are essential to prevent this. Another challenge is maintaining humidity and temperature in environments not naturally suited to mushrooms. In the UK, indoor growing often offers more reliability than outdoor growing, particularly in cold winters. Despite these difficulties, many gardeners find mushroom cultivation rewarding precisely because it requires care and attention to detail.
The sustainability of growing mushrooms
Mushrooms are not only delicious but also sustainable. They can be grown on waste materials such as straw, cardboard and coffee grounds, turning by products into valuable food. This makes them an environmentally friendly choice for gardeners interested in reducing waste and growing their own produce. Mushrooms also require relatively little space, making them suitable for urban gardening. For those seeking sustainable food options, mushrooms provide a unique and versatile crop.
Conclusion
So, how do you plant mushrooms? Unlike traditional crops, mushrooms are grown by introducing spawn into organic material and creating conditions that encourage fungal growth. By preparing the right substrate, ensuring warmth, moisture and air circulation, and harvesting at the right time, it is possible to grow mushrooms successfully at home. Whether cultivating button mushrooms on compost, oyster mushrooms on straw or shiitake on logs, the principles remain the same. Growing mushrooms is a rewarding challenge that combines science, patience and creativity, and it brings the satisfaction of harvesting fresh produce that is both tasty and sustainable.
