Winter and spring are usually associated with freezing temperatures. A freeze happens when the temperature falls to—or below--32 degrees F. While your fruit trees might withstand temperatures as low as 28 F, a mere three degrees lower may damage leaves, blooms and fruits. Since fruit trees go dormant during the winter, learning how to protect them from a winter freeze introduces you to measures that differ from the steps to take during a late spring freeze, when the tree may already be budding.
Water your fruit trees repeatedly before the first frost. Even though they are dormant during the winter, trees lose some moisture via new growth and remaining leaves to cold winds and dry weather conditions. This results in dehydration that eventually causes winter burn. Although this condition mostly affects evergreens, it also applies to deciduous trees.
Wrap light colored tree guards around the trunks of fruit trees. The winter sun warms the dark trees’ surfaces, which may cause them to heat up past the air temperature. The increase in heat stimulates the cells below the tree bark to become active, but the speedy cool down caused by the setting winter sun results in the cells’ death; the name of this condition is sun scald. The light colored tree guards reflect the sunlight back and allow the tree to remain dormant.
Spread mulch around the fruit trees’ drip line. Create a mulch blanket of about two to four inches. Do not mulch the area right around the tree trunk. The mulch slows moisture loss from the soil and provides a bit of insulation against sudden temperature changes.
Late Spring Freeze
Spread frost cloths over your fruit trees. When temperatures may fall to 20 or 30 degrees overnight, the coverings conserve the warmth and humidity that buds and leaves give off. This may prevent frost damage to the future blooms and fruits.
String strands of traditional outdoor Christmas lights around the trees’ branches and trunk. Turn on the lights and leave them lit overnight. The light bulbs give off just enough heat to help raise the temperature to protect leaves and buds from freezing.
Spray your fruit trees with a continuous mist of water with the spray nozzle attachment on your garden hose. Water freezes at 32 degrees Fahrenheit, and continuously spraying your trees with water ensures that the leaves hit by the water experience this temperature. While it is true that the water eventually freezes, the process of changing from liquid to solid releases energy, which in turn warms the plant.