Cold air and frost can damage the woody tissue of fruit tree branches and trunks. Freezing temperatures can also cause the bark to split, twigs to break and fruit or buds to die. Protect your fruit trees before the temperature drops and stave off the detrimental effects of a freeze.
Water the soil thoroughly when freezing temperatures are expected. Soil that has been thoroughly watered will absorb radiation from the sun more readily than dry earth will. This radiation will provide heat to fruit trees, even at night.
Apply mulch to the ground surrounding fruit trees. A thick blanket of mulch provides heat and protection from frost. If your fruit trees already have mulch, remove it to prevent damage from established pests, mold or mildew. Apply 4 to 6 inches of fresh mulch.
Cover the branches and limbs with old sheets, quilts or black plastic sheeting. However, foliage that comes into contact with the cover may be damaged by the transfer of heat. Another option is to pitch several lengths of PVC pipe around the fruit trees and create a tent with a cover. The cover material should reach the ground for maximum protection. Remove the cover on sunny days.
Cover the trunk. If you live in a region that experiences frequent freezing temperatures, cover the trunk in commercially available foam, fiberglass or paper tree wrap. Remove tree wraps in the spring.
Wrap the tree in holiday lights. The small lights provide a safe source of heat that will protect many fruit trees, especially citrus, from frost and freezing temperatures. Wind strands of small lights around the canopy and turn them on before the temperature drops.