How to Grow Edible Mushrooms? A Detailed Guide to High-Yield Cultivation Techniques

The edible mushrooms currently cultivated on a large scale, such as oyster mushrooms, shiitake, enoki mushrooms, lion's mane mushrooms, wood ear, silver ear, and button mushrooms, can be roughly divided into the mycelium stage and the fruiting body stage, or two growth and development periods. The conditions required by each mushroom during these two stages have similarities as well as differences. This is determined by their biological characteristics; if the favorable conditions they need can be created, high yield and good quality can be achieved.

1. Nutrients, mainly carbon, nitrogen, and mineral elements

1. Carbon nutrients are the main components making up the mycelium and fruiting bodies, and are also the source of energy needed for their growth and development. Carbon substances account for about 50%-65% of the mushroom body composition (dry matter). The cottonseed hulls, sawdust, and other culture media used in cultivation are the main source of carbon.

2. Nitrogen nutrients are the main raw materials for proteins and nucleic acids. They are likewise major components of the mycelium and fruiting bodies, and are also the material basis for the savory, delicious flavor of edible mushrooms, especially the abundant amino acids (as many as 18 kinds), which cannot be formed without nitrogen.

For the normal development of edible mushrooms, carbon and nitrogen nutrients not only need to be present in sufficient quantities, but their ratio must also be reasonable, commonly known as the carbon-to-nitrogen ratio. For various mushrooms, this ratio is preferably 20:1 during the mycelium growth stage and 30-40:1 during the fruiting body development stage. In production, because the types of culture materials differ, wheat bran, cornmeal, soybean cake powder, ammonium nitrate, urea, etc. are sometimes added to adjust the carbon-to-nitrogen ratio. Applying the same formula to every mushroom alike, or even not using materials according to the original formula and changing things arbitrarily, with this missing and that lacking, makes it difficult to achieve high yield and good quality.

3. Mineral elements. The normal growth of edible mushrooms also requires mineral elements and trace elements such as calcium, magnesium, phosphorus, potassium, iron, and zinc. Although these substances are needed only in small amounts, they are all important, and generally the content in the main materials can meet the need. Sometimes magnesium sulfate, plant ash (potassium), and chicken manure (phosphorus) are also added.

2. Water and Humidity

Water is one of the main components of the mycelium and fruiting bodies, and more importantly, metabolism, the activity of life, cannot proceed without water. Fresh mushroom bodies contain as much as 85%-90% water. The water in the culture medium is the main source of water needed for the growth and development of edible mushrooms, but too much water is instead harmful. The suitable water content is 65%-75%. The standard is that the material has absorbed enough water so that when squeezed in the hand, water appears between the fingers but does not drip down. Taking cottonseed hulls as an example, the weight ratio of material to added water is roughly 1:1.2-1.5; adding too much will hinder mycelial growth.

Humidity mostly refers to relative air humidity. This not only has a direct relationship with the growth and development of edible mushrooms, but also affects the release of water within the material. Especially during the fruiting body development period, if humidity is insufficient, yield will certainly be reduced; if it is below 60%, the fruiting bodies will not grow; if it is below 45%, the primordia stop differentiating, and existing primordia may even die. The suitable air humidity is 85%-93% (during the fruiting body growth period). During cultivation, adding water by spraying to raise the relative air humidity is a necessary measure. Especially in the later stage, injecting water into the culture medium or soaking the culture medium can also correspondingly increase yield.

3. Temperature

All mushrooms require certain temperature conditions to grow and develop normally. The temperature requirements of the mycelium and fruiting bodies during growth and development differ, and some even "like" fluctuating temperature conditions; for example, if oyster mushrooms can be given a 10°C temperature difference stimulus each day, this favors the formation and development of fruiting bodies. For the several mushrooms cultivated more commonly listed above, the suitable temperature for mycelial growth is roughly around 25°C (30°C for wood ear), and the suitable temperature for fruiting body development is generally around 15°C. Straw mushrooms like warmth; the mycelium develops better at 35°C, and the fruiting bodies develop well at 30-32°C.

Temperature is an important factor affecting the growth and development of edible mushrooms. In production, natural seasonal cultivation is currently mostly used, mainly arranging production according to natural temperature conditions (artificial air conditioning is also mainly used to create temperature conditions). With advances in science and technology, edible mushroom varieties are now being improved, and changing their temperature characteristics is one of the main goals; for example, for oyster mushrooms and shiitake, low-temperature, medium-temperature, and high-temperature types have already been bred, and even wide-temperature types with less strict temperature limits. From this, corresponding varieties can be selected according to the temperature conditions of the cultivation period, extending the cultivation period.

4. Oxygen and Carbon Dioxide

If various edible mushrooms lack sufficient oxygen, mycelial growth will be poor, and the fruiting bodies will also grow poorly. Because during growth and development the edible mushrooms themselves also release carbon dioxide, the cultivation site must be ventilated and aired.

5. Light

Edible mushrooms do not have high light requirements; the mycelium can grow under dark conditions. During fruiting body differentiation and growth, a certain amount of scattered light is needed, and direct strong light should be avoided. In complete darkness, fruiting body development is poor and slow. Light can increase their color; without light, the color is pale. Light is also related to temperature. In the north, using greenhouses to cultivate edible mushrooms requires sunlight to raise the temperature, but care must be taken to prevent excessively high temperatures; when the light is too strong, straw curtains and the like are mostly used for shading.

6. pH

Edible mushrooms mostly prefer a slightly acidic environment; generally the pH value does not exceed 7 (neutral), and is about between 5.5-6.5, but oyster mushrooms are relatively tolerant of alkali and can also grow at pH 8. Lion's mane mushrooms, however, are acid-tolerant and can also grow at pH 5. During cultivation, substances that turn acidic, such as sugar, will be added, and the high-temperature sterilization process will also make the culture medium acidic. Attention should also be paid to the local water quality, that is, its pH value. When mixing materials, attention should be paid to creating a suitable pH environment; sometimes lime is added, or acidic fertilizers such as ammonium nitrate are added, which first increases

calcium and nitrogen, and second can adjust the pH value of the culture material.

To prevent excessive acidity or alkalinity, adding a certain amount of gypsum can serve a buffering effect.