Chris Oswalt, University of Florida Institute of Food and Agricultural Sciences citrus Extension agent for Polk and Hillsborough counties, discusses passive and active cold-protection practices for citrus trees.
“Passive practices are those things that growers would intentionally do before typically planting the grove,” Oswalt says. Site selection, including planting on higher elevations that are warmer than lower cold-pocket locations, is a prime example. Row-middle management to keep weeds from interfering with solar radiation getting into the soil where it is released at night is another passive practice, as is avoiding nutritional and water stress. An additional passive cold-protection practice is choosing rootstock-scion combinations that have cold tolerance.
Active practices are those that growers initiate shortly before or during a freeze. One active practice is using wind machines in cold pockets to mix the air so it becomes warmer. Microsprinkler irrigation has been the most widely used active cold-protection method for Florida citrus in recent decades.
“You need to consider when to start those irrigation systems based on the temperatures and when they are going to get close to freezing because you don’t want your irrigation system or your emitters to get frozen before you have a chance to start the irrigation system,” Oswalt says. Growers need to ensure they run the irrigation system long enough, he adds.
Oswalt also briefly discusses older cold-protection practices, including tree wraps and soil banks.
Hear more from Oswalt:
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