Detailed Guide to High-Yield Cultivation of Nameko Mushrooms (Part 2)

V. Management During the Fruiting Body Stage

1. Unwrapping and Scoring the Blocks Once the spawn-running stage of the blocks is complete and the blocks have formed, fruiting management should be carried out according to temperature conditions. In late August, as temperatures gradually drop, open the plastic sheeting on the mature blocks and place them on the fruiting racks. The mycelial film that grows on the blocks is too thick, which is unfavorable for the emergence of fruiting bodies, so a bamboo knife or iron nail should be used to score lines on the surface of the blocks, cutting crisscross into squares about 2 cm wide. Score through the mycelial film, with appropriate depth, generally 1 cm deep is sufficient. Scoring too deep makes the blocks prone to breaking. Then place them flat on the racks, spray water, and adjust the room temperature to around 15°C to promote the formation of fruiting bodies.

2. Temperature Management Nameko mushrooms belong to the low-temperature type; fruiting bodies grow best at 10-15°C. Above 20°C, fruiting bodies form slowly, the caps are small, the stems thin, the flesh thin, and the caps tend to open. Fruiting bodies have strong resistance to low temperatures and can still grow at around 5°C, but not vigorously. Under alternating temperature conditions, fruiting bodies grow extremely well, with high mushroom production, large fruiting bodies, thick flesh, and good quality.

After September, the natural temperature difference is large, so the natural temperature difference should be fully utilized to promote higher mushroom production. At night, the temperature of the fruiting room should not be lower than 10°C. At noon, when the temperature is high, attention should be paid to ventilation so that the fruiting room temperature does not exceed 20°C. Production practice has shown that if the outdoor temperature in early autumn is not higher than 25°C, and the outdoor temperature in late autumn does not freeze, the fruiting room only needs cooling in the early stage and slight insulation in the later stage, along with attention to water spraying and ventilation, and the fruiting bodies can grow normally.

3. Humidity Management Moisture is one of the important conditions for high-yield Nameko mushrooms. If humidity is insufficient, fruiting body differentiation is inhibited, the fruiting bodies shrink, do not secrete mucus, stop growing, or die. To ensure the growth and development of fruiting bodies, water should be sprayed appropriately to increase the moisture of the blocks and the air humidity. Spray water at least 2 times a day, and the amount of water sprayed should be determined according to the indoor humidity and the growth of the fruiting bodies. Air humidity should be maintained between 85% and 95%. In dry weather with strong wind, the frequency of water spraying should be appropriately increased. The more fruiting bodies occur, the more vigorous the growth of the fruiting bodies and the greater the metabolic capacity, so the amount of water needs to be increased. After scoring the surface, when the temperature has not yet stabilized below 20°C, within 10 days after wrapping, spray less and lightly, keeping the surface of the medium moist. When the temperature drops below 20°C, that is, in early September, increase the amount of water and spray 3-4 times a day. The water for knot formation is very critical, determining how early or late fruiting occurs and the yield. When spraying water onto the blocks, use a sprayer to spray finely and frequently, so that the water slowly penetrates into the blocks through the surface score lines; do not spray with a strong or heavy stream. When spraying, hold the sprayer head higher to prevent the water from striking the fruiting bodies. In winter, do not spray water that is too cold; the water temperature should be close to room temperature. In winter, room temperature is very low, and spraying too-cold water will lower the block temperature, inhibit mycelial activity, reduce the decomposition ability of the mycelium, slow the growth of fruiting bodies, or even prevent fruiting, and can easily cause black spot disease. If using tap water, it must be stored for 2 days to allow the chlorine to evaporate before use; well water is best. There should be no standing water on the top or bottom of the blocks. In winter, if heating equipment is used in the fruiting room, do not apply water before heating; spray water only after the room temperature has risen for 2 days.

4. Ventilation Management During the fruiting period, the respiratory energy of the mycelium increases, and the oxygen demand increases markedly, so the indoor air must be kept fresh. While ventilating, pay attention to changes in temperature and humidity. If the temperature is high and the room is stuffy, hot, and humid, ventilation should be strengthened. During the fruiting period, if the natural temperature is relatively high and indoor ventilation is poor, it can result in no fruiting or an increase in deformed mushrooms. In addition, in seasons with higher temperatures, ventilation openings and exhaust holes must be opened day and night to allow air convection and ensure sufficient oxygen indoors.

5. Light Management Fruiting bodies need diffused light during growth, the blocks should not be placed too densely, and the room should not be too dark. Without enough scattered light, the fruiting bodies are pale in color and have thin, elongated stems; it is suitable to have diffused light similar to that of a shaded shed.

The length of the fruiting period depends on the level of management. With good management and suitably adjusted conditions, the mushroom flush cycle is short, fruiting is fast, and the yield is high, so the cultivation cycle can be ended early. If management is poor, fruiting is late, the mushroom flushes come slowly, and the yield is low. In severe winter, if the Nameko mushroom production cycle is not yet finished and the mushroom flushes are still vigorous, and if the weather is too cold, protective measures can be implemented by appropriately raising the indoor temperature to facilitate continued mushroom production. In rural areas without formal insulated mushroom houses, the blocks can be piled together and covered with plastic sheeting to prevent dry air from drying out the blocks, maintain mycelial vitality, and still continue fruiting the following spring when the temperature rises above 5°C.