1. Overwintering management: Ensure leeches to overwinter safely. After winter, when the temperature drops below 10℃, leeches stop feeding and hibernate under soil or leaves. Leeches released in early spring have generally grown into adults and can be processed and sold. When fishing, drain the water first, then fish it up with a net, and choose large and strong seeds, each mu 15 ~ 20 kg, and put them in the breeding pool for the winter. It can drain water for winter.
After drainage, straw or wooden poles can be covered on the pool surface to prevent freezing and keep the soil moist. You can also bring ice for the winter, and the pool water should be properly deepened to prevent complete freezing.
2. Overwintering in greenhouse: Due to the geographical influence, artificial sunlight overwintering greenhouse should be established for leech breeding in northern China to break its overwintering habit, increase the breeding time and shorten the listing cycle. Generally, the solar greenhouse is of bamboo and wood structure. The north wall is made of soil or brick, with a thickness of 0.8- 1.5m, an east-west direction and a length of 30-50m, with a north-south span of10-0/5m and 5-7 rows of main columns.
Covered with non-dripping plastic film and coiled straw mulch, leaving doors, passages and tuyeres. In the cold and snowy season, snow removal and artificial warming measures should also be taken. Advanced greenhouses can be made of plastic steel without columns, but the cost is relatively high.
3. Building a solar greenhouse: grasping the big and releasing the small in a planned way, and concentrating on wintering. In daily management, we should pay close attention to the temperature changes inside and outside the greenhouse, increase oxygen, resist wind and cold, ensure the normal growth and overwintering of leeches, and prepare enough leeches for the coming year.