December 20, 2012 Freeze
We woke up this morning to a winter wonderland, but not of snow. We rarely get snow in the central San Joaquin Valley. Frost, on the other hand, is not uncommon this time of year. About every three to five years we get a hard frost (low 20s to high teens F.). This is NOT good. Tulare County, where we live, is a large citrus growing area with over 111,ooo acres of trees. A hard frost can cause severe damage, not only to the fruit, but to the local economy as well.
We only have a few trees in our family orchard in the front of the house. We set up a sprinkler to protect the orange, lemon, and pummelo trees.
Young stone fruit trees are also susceptible to frost damage. According to our thermometer, it got down to 28 degrees last night. This could be a problem. Potential damage also depends upon how long it stays cold, however. Kind of like frostbite in humans. The longer it stays below freezing, the greater the chance of damage.
Some larger growers have wind machines to protect the fruit. Others run irrigation water or sprinklers. The purpose of the wind is to create turbulence that mixes warm from higher in the air with cold air so that the air around the tree stays warmer. The water or sprinklers create a freezing fog or ice covering so that the temperature stays at 32 degrees. Lemon trees are more delicate than orange trees. The problem with using sprinklers is that sometimes the limbs break because of the weight of the ice.
The fruit damage may not show up right away, though. What causes damage is when the little juice cells freeze, they expand, like ice cubes, and the tiny walls or membranes break down. This makes them dry out so that the citrus is not as juicy, and, thus not as sweet. Learn more about frost protection for citrus here. See more of Jack Frost’s Handiwork here.
What’s the weather like in your neck of the woods?