Q. My peach tree is in full bloom and I just saw a weather report that hard frosts are expected next week. Will this damage my tree?

 A. You are not alone. Many of our trees here at the college are in full bloom as well. 

The 70-degree weather we had in January fooled many of the trees into thinking it was spring. It is not uncommon for us to get a killing frost while our fruit trees are in bloom. In the Redding area we can have hard frosts well into April and even later in the mountains and surrounding foothills.   

Seasoned gardeners can all tell you horror stories about a late frost leveling their spring plantings. This is why early blooming trees, such as cherry and apricots, are unreliable producers of fruit in our area. 

What is unusual about this year is that trees are blooming so early and we could easily have another couple of months were temperatures can get well below freezing. The freezing temperatures will defiantly damage the flowers on the tree and any potential fruit production for this year will be lost. 

If the temperatures are low enough it may also cause damage to the leaf buds and branches as the tree is no longer dormant.

To protect the trees from the cold there are several things you can try depending on the number of trees you have, their size, location, and the severity and length of below-freezing temperatures.

You can build tripods out of light lumber or PVC pipe around each tree and cover them with frost cloth, blankets or tarps. I have used the same structure I use to support my bird netting to cover my tree with an old tarp. Do not use plastic or sheets as they do not provide enough insulation.   

Another option is to hang the trees with the old-fashioned Christmas lights, however these are getting harder to find. They need to be the big bulb type, the newer LED Christmas-tree lights won’t work since they’re cool burning and won’t give off sufficient heat. You can improve the protection by also covering with a blanket or tarp. 

Another option is to turn a sprinkler on your trees just as the freeze begins, to coat them with ice. Although it seems counterintuitive, the ice will protect the tree because the temperature beneath the ice will not drop below 32 degrees. For this method to work you will need to keep the sprinkler on until the temperatures rise above freezing. If you plan to use this method of frost protection and the cold temperatures last for a while, monitor to ensure that you are not creating a flood somewhere else.

You may have noticed that some of the big orchards and vineyards use big fans to create air turbulence to protect trees from freezing. I do not like to recommend use of the fan for residential yards for a couple of reasons. First, most of you do not have a large enough fan to create enough air turbulence to be effective in protecting the tree. And if you do just happen to have a giant fan at your disposal you can cause increased damage to surrounding areas by moving the cold air into neighbor’s yard.



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