Key Points for Cold and Frost Protection in Winter Planting of Chinese Medicinal Herbs

       Winter is a cold season, and due to the increasingly variable global climate, extreme severe cold weather occurs in many regions, making overwintering medicinal plants highly susceptible to frost damage. If relevant measures are not taken in time, the growth and yield of the following year will be affected. So how can we help medicinal plants safely through the cold season in winter? Here are several common simple methods for cold and frost protection in medicinal herb cultivation:

　　1. Earthing up and mounding around the roots:In winter, in combination with intertillage and clearing of drainage ditches, carry out earthing up and mounding around the roots, that is, build up relatively dry soil around the base of the plants (mound soil 40-60 cm high around tree bases), so that the depth of the root system is correspondingly increased, reducing or avoiding damage to the roots caused by low-temperature frost.

　　2. Whitewashing tree trunks:By making use of the reflective effect of white color on light, whitewash the tree trunks to reduce the temperature difference between day and night in the tree body and prevent frost injury to the trunks. The whitewash formula used is: quicklime 1.5 kg, salt 0.2 kg, sulfur powder 0.3 kg, a little grease, water 5 kg, mixed into a paste-like solution.

　　3. Mulching with straw:Cover the spaces between rows of medicinal herb plants with straw, thatch and other crop stalks. This can both keep the ground temperature relatively stable and prevent cold wind from directly attacking the plant roots. For frost protection of herbaceous medicinal herb seedlings, first cover with a layer of plant ash, then protect with plastic film in a framed shed. For frost protection of woody medicinal herb seedlings, the whole tree can be wrapped and bound with rice straw or wheat straw, and soil should be mounded and pressed firmly around the main trunk near the ground.

　　4. Wet-material smoking:On nights or early mornings when frost is about to occur, pile wet weeds, leaves, sawdust, grain husks and other materials at the upwind position of the medicinal field and set them on fire. The smoke formed after the smoke piles are lit can ease the drop in temperature and has an obvious effect on frost protection. Generally, 8-10 smoke piles should be lit per mu of medicinal garden. It should be noted that the smoke piles should be lit when the outside temperature is 10-2°C lower than the temperature at which the crops suffer damage.

　　5. Heavy application of winter manure:Before the soil freezes, apply 1500-2000 kg of farmyard manure per mu between the rows of medicinal herb plants. This can not only raise the ground temperature and provide frost protection and warmth, but also serve the purpose of winter fertilizer for spring use and improve soil fertility.