Methods for protecting walnut trees from the cold in winter: good management for a safe overwintering

    Cold-protection measures can be carried out after the walnut trees drop their leaves (generally from mid-November to early December). 

    1. Burying in soil for cold protection

    For 1-2 year old young trees that cannot overwinter safely in the open field, bend the entire tree body to one side and cover it with soil. This method is the most effective and reliable measure for preventing twig dieback. 

    2. Mounding soil for cold protection

    Build a mound of soil within a 30 cm range around the base of the seedling to prevent frost injury to the root crown and graft union. Remove it in spring of the following year after the temperature rises and stabilizes, and level the tree plate. 

    3. Whitewashing for cold protection

    Whitewashing young trees can ease the temperature difference between the sunny and shady sides of the trunk and gives a relatively good cold-protection effect. It can be applied before the soil freezes. The formula for the whitewash is: 0.5 kg table salt, 6 kg quicklime, 15 kg clean water, plus an appropriate amount of adhesive and residue of lime sulfur mixture, applied evenly over the trunk and branches of young trees.
 
    4. Coating trunks with polyvinyl alcohol

    Use properly boiled polyvinyl alcohol to evenly brush the main trunk of the seedling. The method for boiling polyvinyl alcohol is: mix polyvinyl alcohol and water at a ratio of 1:15-20, then boil. First heat the water to about 50°C, then add the polyvinyl alcohol (do not add it after the water has come to a boil, otherwise the polyvinyl alcohol cannot dissolve completely and the solution will be uneven), stirring while adding, until it boils, then simmer over low heat for 20-30 minutes and it is ready. Use it after the temperature drops to where it is not hot to the touch.