Mushroom Cultivation: An In-Depth Guide

Mushrooms are a fun and delicious food to cook with and can be a great addition to homemade pizzas, burgers, steaks, and salads. They are also highly nutritious. While mushrooms are not plants or animals, they are a type of fungus that requires different conditions and equipment to grow than plants. Mushrooms can be grown commercially or at home, and there are many techniques to do so. For example, mushrooms can be grown on logs placed outdoors or in containers with various substrates, such as compost, straw, or coffee grounds. They can also be grown indoors, where they are less exposed to the environment, and require less space.

Mushrooms are fungi, not plants

Mushrooms are a type of fungus, and while they may be commonly considered vegetables due to their usage in food, they are not part of the plant kingdom. The distinction between mushrooms and plants is important as it affects how we understand, support, and engage with these organisms.

Taxonomists use six broad categories to organize all living things: Archaebacteria, Eubacteria, Protista, Plants, Fungi, and Animals. Fungi, including mushrooms, were historically classified as plants, but this is no longer the case. The French entomologist René Antoine Ferchault de Réaumur, for example, described fungi as pathogenic to insects, indicating a distinction from plants.

Fungi are more closely related to animals than to plants. Molecular evidence demonstrates that fungi share a more recent common ancestor with animals than with plants. Fungi, unlike plants, do not have chlorophyll for food production, and they do not eat or digest food like animals. Instead, the mycelium of a fungus grows into and around its food source, secreting enzymes for external digestion, and then absorbs the already digested nutrients.

The mushroom is the fruiting body of a fungus, akin to an apple that spreads spores similar to how a fruit spreads seeds. The mycelium of the fungus grows underground, similar to the roots of a plant, while the mushroom fruits above ground. The largest recorded living organism is a mushroom ring of mycorrhiza, a mutualistic symbiotic relationship between the mushroom's roots and the roots of nearby plants.

In summary, mushrooms are fungi, not plants, and this classification has important implications for our understanding and engagement with these organisms. Fungi have unique characteristics and a distinct evolutionary history that sets them apart from plants and animals.

Different types of mushrooms

Mushrooms are fungi that require specific conditions and equipment to grow, unlike plants. The growing process often begins in a laboratory, where spores are inoculated into sterile cereal grains and incubated. The substrate, or growing medium, is then prepared, typically using synthetic compost or manure-based compost. The pasteurized substrate is placed in trays or beds, and spawn is mixed in, with a top layer applied. The temperature and humidity are carefully controlled throughout the growing period. After about three weeks, the first mushrooms are ready for harvest, which is done entirely by hand.

There are various types of mushrooms, each with its own unique characteristics and growing requirements. Here is an overview of some of the different types:

Shiitake Mushrooms

Shiitake mushrooms are one of the oldest cultivated varieties and are widely grown globally, contributing to a quarter of annual mushroom production. They can be cultivated using the traditional \"soak and strike\" method on logs or the more modern and efficient bag method using hardwood sawdust. Shiitake mushrooms are versatile and can be used fresh or dried, offering a long shelf life and medicinal benefits.

Oyster Mushrooms

Oyster mushrooms are widely cultivated and also grow wild. They are one of the easiest mushrooms to grow at home, making them a popular choice for beginners. Oyster mushrooms have a mild and sweet flavor, providing a gentle introduction to more adventurous varieties. They fruit in the spring, and their cultivation does not require high temperatures, making them suitable for cold climates.

Portobello Mushrooms

Portobello mushrooms are the mature form of button mushrooms, featuring a fully open cap and a more prominent meaty texture. They are larger than cremini or button mushrooms but retain a mild flavor. Portobellos are versatile in the kitchen and can be used as vegan burgers, stuffed, or baked.

Milky Mushrooms

Milky mushrooms thrive in warmer climates with temperatures above 30 degrees Celsius. They have large fruiting bodies with thick, solid stems and a meaty texture. Milky mushrooms are high in ergothioneine, a powerful antioxidant, and have a long shelf life. They are widely cultivated in India, with an annual production exceeding 40,000 tons.

Morel Mushrooms

Morel mushrooms are highly prized for their nutty, earthy flavor and meaty yet tender texture. They are typically found in the spring, and their specific growing requirements make them challenging to cultivate. Morel enthusiasts often have secret "morel spots" they return to annually for harvesting. It is important to distinguish between the edible "true morels" and the poisonous "false morels."

Black Poplar Mushrooms

Black poplar mushrooms, also known as piopinno or piopinni, primarily grow on hardwood and produce beautiful clusters of fruit. They are relatively easy to cultivate and are gaining popularity among small-scale growers, especially in Japan and Korea, where bottle farming technology is used. Black poplar mushrooms have a nutty flavor and are a wonderful addition to various dishes.

The diversity of mushroom varieties offers a range of options for growers, from beginners to experienced cultivators. Each type has its own unique characteristics, flavors, and growing requirements, contributing to the fascinating world of mushroom cultivation.

Growing mediums and substrates

Mushrooms are fungi and require different conditions and equipment to grow than plants. The entire growing process begins in a laboratory where the spores are inoculated into a sterile growing medium called a substrate. This is because mushrooms are easily contaminated.

The substrate is a key ingredient in mushroom production and there are two types of starting material generally used: synthetic compost or manure-based compost. Synthetic compost consists of wheat or rye straw, hay, crushed corn cobs, cottonseed meal, cocoa shells, and gypsum. Manure-based compost is made from stable bedding from horse stables or poultry litter. An ideal substrate will contain enough nitrogen and carbohydrates for rapid mushroom growth.

Once the substrate is prepared, it is placed in stacked wooden trays or beds in the growing house. The spawn is mixed in, and a top layer is applied, usually peat moss. It takes about three weeks to produce the first mushrooms, and temperature and humidity are carefully controlled throughout the growing period. Mushrooms mature at varying times, so they are picked by hand continuously for two to three weeks.

Different types of mushrooms require different substrates and growing conditions. For example, Shiitake mushrooms can be grown on hardwood logs, including oak, American beech, sugar maple, and hophornbeam, or in containers. Oyster mushrooms are grown on a substrate of sterilized wheat, paddy straw, or used coffee grounds, and they do not require much space. Pleurotus mushrooms can be grown on carbonaceous matter such as straw or newspaper.

Contamination and sterile conditions

Mushrooms are easily contaminated and require sterile conditions to grow. The entire growing process often begins in a laboratory, where spores are inoculated onto sterile cereal grains and incubated until they develop into a viable product. Wild harvests, outdoor log inoculation, and indoor trays can all provide the correct combination of humidity, temperature, substrate (growth medium), and inoculum (spawn or starter culture) necessary for mushroom growth.

While mushrooms can be grown outdoors on logs, as has been done for hundreds of years, they are also commonly grown indoors in containers or on shelves, as they do not require sunlight. This method allows for greater control over the growing environment, as temperature and humidity must be carefully monitored throughout the growing period.

The substrate, or growing medium, is a key ingredient in mushroom production. Two types of starting material are generally used for mushroom substrate: synthetic compost, consisting of wheat or rye straw, hay, crushed corn cobs, cottonseed meal, cocoa shells, and gypsum; or manure-based compost made from stable bedding or poultry litter. Oyster mushrooms, for example, are grown in a substrate of sterilized wheat, straw, and even used coffee grounds. An ideal substrate will contain enough nitrogen and carbohydrates, such as chitin, for rapid mushroom growth.

After the substrate is prepared, it is pasteurized and placed in stacked wooden trays or beds. The spawn is mixed in, and a top layer, usually peat moss, is applied. From this point, it takes about three weeks to produce the first mushrooms for harvest. Mushrooms mature at varying times, so hand-picking is continuous for two to three weeks. After harvesting, the growing area is pasteurized with steam before a new crop is started.

Harvesting and picking mushrooms

When harvesting mushrooms, it is important to be ecologically conscious. The actual picking of mushrooms is completely sustainable, but trampling native plants, compacting the earth, and causing erosion can harm the local ecosystem. Therefore, it is recommended to carry small baskets to a central location, rather than dragging heavy harvests around with you as you pick. This is easier on your back and on the forest floor. It is also important to leave no trace of litter or debris behind.

When picking mushrooms, it is important to ensure that they have reached a point at which they have dropped a significant proportion of their spores. This varies between species. For example, don't pick hedgehog mushrooms, winter chanterelles, and other small mushrooms that have a cap diameter of less than 2 cm. On the other hand, ensure boletes, horse mushrooms, parasols, and other larger mushrooms have caps larger than 4 cm in diameter.

There are two main methods for harvesting mushrooms: cutting and picking. Cutting minimises disturbance to the surrounding area and can make preparation easier, but it is important to identify the mushroom correctly before cutting, as some mushrooms require uprooting to be accurately identified. When cutting, use a small blade to remove debris and trim the mushrooms in situ, so that dirt doesn't get lodged in the gills or pores. Dispose of mushroom trimmings in a similar habitat to where they were picked, as this supports mycological diversity.

When picking mushrooms, it is important to be gentle and not to damage the surrounding area. Picking mushrooms is similar to picking apples, but it is important to be careful not to damage the underlying organism, which can reduce the lifespan of the mushroom. Mushrooms that grow on trees should be cut away from the tree to avoid damaging the tree.

Frequently asked questions