What environmental conditions does straw mushroom (Volvariella volvacea) need to grow?

1. Temperature: Straw mushroom is a high-temperature type agaric mushroom. The temperature required for spore germination is 25-45°C, with 40°C being optimal; above 45°C or below 25°C, germination cannot occur. The temperature range that straw mushroom mycelium can adapt to for growth is 20-40°C, and the most suitable temperature for growth is 35-36°C; at this temperature, the mycelium grows fastest. Below 15°C or above 42°C, the mycelium grows slowly, stops growing at 10°C, and dies quickly below 5°C. The suitable temperature for fruiting body development is 28-32°C, with 27-32°C being most suitable; below 24°C, fruiting bodies are difficult to form. Straw mushrooms grown at high temperatures above 35°C mature earlier and tend to open their caps, and the fruiting bodies are smaller.

2. Moisture: Straw mushroom prefers to live in a humid environment, and can only produce mushrooms under high temperature and high humidity. With insufficient moisture, when it is only 50%, the mycelium grows slowly and fruiting bodies are difficult to form; when moisture is below 65%, the surface of the fruiting bodies is lusterless and has uneven wrinkles. However, too much moisture will cause poor ventilation, resulting in rotten and dead mushrooms. The suitable water content of the straw pile is about 75%; if below 60% or above 90%, it is unfavorable for the growth and development of straw mushroom. The suitable relative air humidity is 80% during the mycelium growth stage and 85%-95% during the fruiting body development stage.

3. Air: Straw mushroom is an aerobic fungus. During the mycelium growth stage, only a small amount of ventilation is needed, and a short period of ventilation each day is sufficient. During the fruiting body development stage, more oxygen is needed, especially when the mushroom body is growing rapidly, the circulation of fresh air is even more important. Because mushroom body growth requires a large amount of oxygen, if oxygen is insufficient and carbon dioxide accumulates too much, the growth of fruiting bodies will be inhibited. Therefore, the water content of the compost pile should not be too much, and the straw pile should not be too large or too thick; when ventilating the mushroom yard, ventilation should not be too fast or too long, so as to avoid excessive evaporation of water.

4. pH: Straw mushroom is suitable for growing under slightly alkaline environmental conditions. The pH value for normal mycelium growth is 4-8, but 6.2-7.5 is the most suitable, when the mycelium grows vigorously. When the pH value is below 3 or above 9, the mycelium is inhibited. It has been reported that straw mushroom mycelium can still grow slowly at a pH value of 12, so in production practice it is best to control the pH value of the culture material at around 8, which can effectively prevent contamination by weed molds. The suitable pH value for fruiting body formation of straw mushroom is 5.0-7.0.

5. Light: The basidiospore germination and mycelium growth of straw mushroom do not need light at all, but scattered light is one of the conditions that promote fruiting body formation; in darkness, the mycelium will not form fruiting bodies. Likewise, strong direct light has an even more serious inhibitory effect on mushroom body growth, so straw mushroom prefers semi-shaded scattered light. Suitable scattered light can promote the formation of fruiting body primordia, make growth robust, enhance disease resistance, and facilitate pigment transformation. When cultivating straw mushroom in the open field, a straw cover can be applied to avoid strong direct light and at the same time avoid massive evaporation of water from the straw pile.