Key Technical Management Points for the Spawn-Running Period of Autumn-Cultivated Oyster Mushrooms

The period from spawning to the appearance of fruiting bodies is called the spawn-running period. The level of technical management during this period determines whether the oyster mushroom mycelium can grow and develop normally in the substrate, and is the key period for achieving high-quality, high-yield oyster mushrooms in the future. Therefore, strengthening management during the spawn-running period of oyster mushrooms is crucial. In my investigations, I have found that many oyster mushroom producers believe oyster mushrooms are easy to grow and manage extensively. After spawning, they often neglect scientific management during the spawn-running period and become careless, which leads to reduced yields and poor harvests of oyster mushrooms, and in severe cases, complete crop failure. To help the vast number of producers correctly master the technical management during the spawn-running period of oyster mushrooms, the key technical management points for the spawn-running period of autumn-cultivated oyster mushrooms are briefly described as follows:

The management during the spawn-running period can be summarized as the management of temperature, humidity, and air.

I. Methods and principles for temperature regulation during the spawn-running period. Oyster mushroom production is divided into two methods: plastic bag cultivation and raised-bed cultivation. Regardless of the cultivation method, after spawning, the natural temperature should preferably be controlled within 28°C, and the substrate temperature must be controlled within 30°C. For bag cultivation, the regulation method is to increase or decrease the number of stacked bag layers. When the natural temperature is above 25°C, the bags should preferably be stacked in a "#" shape in 2-3 layers, and each bag should be spaced 2-3 cm apart to facilitate ventilation and heat dissipation. For raised-bed cultivation, when spreading the substrate and spawning, a ventilation trench 20 cm wide should be left longitudinally in the middle of the substrate bed. After spawning, light should be controlled, especially direct sunlight. When temperatures are high, add straw curtains and pour cold water on the straw curtains to cool them down. If the substrate temperature continues to rise without dropping, the film above the ventilation trench can be raised by 20 cm to accelerate air circulation within the film and lower the substrate temperature.

During the growth and development of oyster mushroom mycelium, a large amount of metabolic activity occurs. In addition, various microorganisms also survive and reproduce in the substrate, with very active metabolism, continuously generating respiratory heat, causing the substrate temperature to gradually rise. Under normal conditions, the substrate temperature is 2-3°C higher than room temperature. If management is neglected and abnormal conditions occur, the substrate temperature can be more than 10 degrees higher. Therefore, for bag-cultivated oyster mushrooms, inspections must be frequent. Once the substrate temperature is found to be rising, the bags should be turned and the stacks rearranged in a timely manner, and ventilation should be strengthened. Otherwise, once the substrate temperature exceeds the limit, it will scorch the mycelium, reduce vitality, and cause massive contamination by Penicillium, Trichoderma, Mucor, Aspergillus flavus, Neurospora, and Coprinus comatus and other weed fungi, leading to production failure.

II. Moisture management. During the mycelial growth stage, generally do not spray water directly onto the substrate surface. If the substrate that has not yet been fully covered by mycelium suddenly encounters unboiled water, it can also lead to massive contamination by weed fungi. Secondly, regarding air humidity, during the spawn-running period, the relative air humidity in the cultivation room and at the cultivation site should be controlled at around 70%-75%. If the humidity is too high, it easily causes weed fungi and pests; if the humidity is too low, the moisture in the substrate evaporates too quickly, causing the water content of the substrate to decrease, both of which affect mycelial growth. Therefore, for bag-cultivated oyster mushrooms, the bag openings should be sealed well, and ventilation should be strengthened when humidity is too high. For raised-bed cultivation, during the spawn-running period, as long as high temperatures do not occur, the film covering the substrate surface generally should not be opened arbitrarily; closed-system spawn running is relatively safer.

III. Ventilation management. Oyster mushrooms are aerobic fungi. During metabolism, they continuously absorb oxygen and release carbon dioxide, causing the carbon dioxide concentration in the air within and near the surface of the substrate to gradually increase. When the proportion of carbon dioxide increases to 1% of the air, it significantly inhibits the growth and development of oyster mushrooms. The mycelial growth rate noticeably decreases and is impeded. Therefore, maintaining fresh air at the cultivation site is an important condition for promoting normal growth. In terms of management, during the early stage of spawn running, ventilation can be reduced due to the small amount of mycelium; in the middle and later stages, ventilation should be increased as the amount of mycelium increases. In hot weather, ventilate in the morning, evening, and at night; when temperatures are low, switch to ventilating around noon. During rainy and high-humidity weather, ventilate all day. In actual production, it is essential to manage flexibly according to different environmental conditions, both meeting the effective oxygen demand for mycelial growth and development and avoiding drastic changes in the micro-environment.