High‑Rack Flower Shiitake Cultivation: Flower Induction, Harvesting and Intermittent‑Period Management

5. Flower Induction

The suitable humidity for mushroom formation is 50%–68%, with an optimal humidity of 50%–55%. The temperature is 8–22℃, with an optimal temperature of 12–16℃. The highest temperature inside the shed should be around 20℃, with a diurnal temperature range of over 10℃, which is suitable for mushroom growth, development, and cracking.

In severe cold seasons, when the daily maximum temperature is below 10℃, the shading materials on the shed can be moved or skylights opened to allow sunlight to penetrate and raise the temperature inside the shed, ensuring the temperature required for mushroom formation. If the temperature and humidity inside the shed are too low, the plastic film around the perimeter of the shed can be lowered to increase temperature and humidity; conversely, the film can be raised to lower the temperature, achieving the opposite effect. A gentle breeze of 2-3 on the Beaufort scale is generally sufficient. Stronger winds will accelerate moisture evaporation from the mushroom surface, causing the small, immature mushroom buds to dry out and become mushy. At temperatures between 5-12℃, the growth of shiitake mushrooms is slow, resulting in thick caps, short stems, and superior quality.

6. Harvesting

Under suitable temperatures, the period from mushroom cultivation to harvest generally takes 8-12 days; in higher temperatures, it takes 6-8 days. Shiitake mushrooms must be harvested during suitable weather. Before rainy weather or when humidity is high, white shiitake mushrooms should be harvested earlier to prevent them from turning into brownish mushrooms or even thickened mushrooms due to high humidity, thus reducing their quality. When harvesting, avoid leaving small sections of the mushroom stem on the substrate to prevent stem rot and mold contamination of the substrate.

7. Intermittent Period Mycelial Growth, Watering, and Fruiting After Each Harvest

After each harvest, the mushroom bags should rest for 15-20 days. Stop watering and maintain a temperature of 20-25℃, relative humidity of 75%-85%, dim light, and proper ventilation. When white mycelium appears in the harvesting holes, it indicates the mycelium has recovered. Then, water should be added and the temperature difference increased to induce fruiting. The next flush of mushrooms will form in 5-7 days, after which normal fruiting management can begin. For stand-up pith mushrooms, watering should be done once per flush. To ensure more even water distribution, water can be injected into the top 1/3 of the pith. After watering, the bottom and top pith can be interchanged. The injection needle for stand-up pith mushrooms should be longer, as water does not seep to the other end of the pith. For specific watering methods, refer to the watering instructions for upright shiitake mushrooms.