How to Resolve the Contradiction Between Heating, Moisture Retention and Ventilation for Edible Mushrooms in Winter

1. Reasonable Heating

Take the oyster mushroom as an example: it stops growing below 5°C. Even for low-temperature strains such as 2006 and Tekang No. 1, although physiological disorders are unlikely to occur at around 4°C, a temperature above 10°C is still needed for good growth. Therefore, heating and moisture retention in winter production become crucial management tasks. Generally, raising the temperature can be achieved by solar warming, burning stoves inside the shed, and other methods. However, when burning stoves to raise the temperature, most mushroom growers often worry about "losing the warm air" and keep the mushroom shed sealed, resulting in severely poor ventilation, accumulation of carbon dioxide, and persistently high humidity, which not only produces deformed mushrooms but also triggers certain infectious diseases. Common cases such as tea-brown mushrooms, crutch mushrooms and cauliflower mushrooms all occur for this reason, and some infectious diseases such as rot disease are also closely related to poor ventilation and excessively high humidity. Solution: Under natural conditions, on clear and fine days, start ventilation after 10 a.m. and finish around 2 p.m. Pull a layer of shade netting or black film over the upper part inside the shed; after uncovering the straw mats, let the sun warm the shed, allowing heat to enter while blocking direct light. During ventilation there will be some degree of temperature drop, but as long as the airflow is not too strong, it may sometimes actually promote mushroom formation and fruiting body development. If conditions permit, a water-temperature air conditioner can be installed, which can effectively regulate and control the temperature, and because the equipment blows circulating air into the mushroom shed, it keeps the air inside fresh and avoids all kinds of problems caused by poor ventilation.

2. Moderate Moisture Retention

Proper water-holding capacity of the substrate and air humidity inside the shed are collectively referred to as moisture. In production, they are generally regulated at 63% and 85%-95% respectively; only in this way can the normal growth of hyphae and fruiting bodies be ensured. Moisture is only one of the conditions for the growth of edible mushrooms, not the only factor; especially during the growth of fruiting bodies, an appropriate amount of ventilation is indispensable. Yet ventilation and the maintenance of humidity are a real contradiction: ventilation lowers humidity. In fact, under certain conditions, such as around noon in winter, because air warmer than the shed temperature is properly let in, the shed temperature can rise slightly, and this triggers evaporation of moisture inside the shed, causing the humidity at that time to rise somewhat. The theoretically required maintenance of about 90% air humidity does not demand that the humidity remain constant; just as temperature variation can stimulate mushroom formation, a certain humidity difference can sometimes also promote mushroom formation. Moreover, when the humidity is relatively low, it can also inhibit the survival and growth of certain diseases. However, according to the different stages of the fruiting bodies, the humidity difference should be controlled within 10%-20% to achieve relatively ideal production results.