What are the technical key points for winter cultivation management and harvest grading of shiitake mushrooms?

Shiitake mushroom is one of the fungi we eat most often in our daily lives. It is delicious and tasty, and whether used in baking, stir-frying, or stewing soup, it can enhance flavor and add freshness. Shiitake mushroom is also known as flower mushroom (huaxun), xiangxin, zhirong, donggu, hougu, huagu, and so on. So how should shiitake mushrooms be cultivated and managed in winter? What are the technical key points? How are shiitake mushrooms harvested and graded?

I. How should shiitake mushrooms be cultivated and managed in winter? What are the technical key points?

1. Scientific inoculation: The deeper the inoculation hole, the more spawn it holds, which helps strengthen the drought resistance of shiitake mycelium. Under relatively constant temperature and humidity conditions, the mycelium in the shiitake spawn block will germinate quickly, increasing the survival rate.

2. Hot water stimulation for primordia: Soaking the blocks in hot water to stimulate primordia can double the yield of the mushroom blocks. The specific method is:

1) Fully color-turn and dry the blocks or logs that have been colonized by mycelium, and select uncontaminated, intact blocks or logs for treatment.

2) Soaking blocks in warm hot water is a good method for stimulating primordia in winter shiitake cultivation. When soaking the blocks, generally heat the water to 33°C, add 0.3%-0.5% Yifuyuan mushroom ecological treasure, then pour the shiitake blocks or fungus logs into the pool and soak for 3-5 hours. If the water temperature drops, add hot water to adjust the water temperature to 18°C-33°C. Remove the soaked blocks, place them at the fruiting site, and cover them with plastic film to maintain their temperature until primordia appear on the blocks, then carry out ventilation and air exchange. During the fruiting period, if the air temperature is low, you can directly spray a diluted mushroom nutrient solution at 18°C-33°C onto the blocks, then cover with plastic film to raise the temperature of the environment inside the film.

3) After the soaked mushroom blocks are covered with film, they should continue to be kept warm. The mushroom primordia can quickly push out of the fungus blocks. At this time, strengthen ventilation and increase the relative humidity of the air. The first flush of mushrooms can be harvested in 10-17 days. After harvesting, uncover the film and let the shiitake mushrooms fully dry for 7-15 days, then soak them a second time with hot water.

4) After harvesting the second flush of mushrooms, a certain amount of nutrients should be supplemented to the shiitake mushrooms.

3. Fruiting care and management: It takes about one week for shiitake fruiting bodies to mature. Management during this period should be as follows: control the room temperature at about 15°C, maintain relative air humidity at about 90%, and carry out alternating wet-dry and cold-hot stimulation. After each batch of mushrooms is harvested, uncover the film and ventilate for 8-10 hours to let the surface of the fungus logs dry slightly, then spray water on sunny days. During the day, cover the film tightly to allow the mycelium to recover and strengthen. After 12 midnight, uncover the film and ventilate for 1 hour to let low temperatures stimulate the mycelium and promote the occurrence of mushroom primordia. This can be done continuously for 3-4 days.

II. How are shiitake mushrooms harvested and graded?

1. Harvesting

Generally, harvest when the mushroom cap has expanded 70-80%, the edge of the cap is still curled inward, and the inner veil under the gills has only recently broken. At this time, the mushroom shape, quality, and flavor are all relatively good. If harvested only when the cap has expanded 90%, because shiitake mushrooms show obvious post-harvest ripening, the cap will still expand, affecting the grade of the shiitake mushrooms. If harvested when the cap is fully expanded, after drying the edge of the cap will curl upward, forming a thin mushroom, the mushroom stem fibers will increase, and the mushroom quality will be relatively poor.

2. Grading

Once the mycelium has formed fruiting bodies, they can grow and develop even at relatively high or relatively low temperatures, but the quality differs. For example, at a relatively high temperature above 20°C, although shiitake mushrooms grow quickly, the flesh is thin, the cap opens easily, the stem is relatively long, and the quality is poor, commonly known as “xiangxin”.

At relatively low temperatures, shiitake mushrooms grow more slowly, but the flesh is thick, the cap is difficult to open, the stem is relatively short, and the quality is relatively good. Especially below 12°C, shiitake mushrooms grow slowly and generally form short-stemmed, thick-fleshed “donggu” (winter mushrooms).

In the early stage of fruiting body formation, if dry weather or frost occurs, they generally will not continue to grow and may even die. However, if the fruiting body has grown to about 2 cm or more and then encounters the above environmental conditions, the surface of the cap will crack into a pattern. Such shiitake mushrooms have the best quality and are called “huagu” (flower mushrooms).

Low temperature or fluctuating temperature plays a good stimulating role in the formation of fruiting bodies. For example, shortly before fruiting, if a low temperature of about 0°C occurs (snow is even better), then it turns warm, or if the weather alternates between cold and hot, centered on 15°C, with daily temperatures fluctuating between 5-20°C, or if the daytime temperature is relatively high (20°C) and the nighttime temperature is relatively low (10°C), under such temperature conditions, high-quality flower mushrooms or winter mushrooms will be formed.

From a production perspective, the temperature is best at 15-18°C, or 20°C during the day and 10°C at night. At such temperatures, growth is both fast, yield is high, and quality is also good.