In January, Florida growers were in the midst of the first deep freeze of the season. Strawberry growers, as well as tomato and pepper growers, had to take action to protect their crops. Ted Campbell of the Florida Strawberry Growers Association, and Gene McAvoy, vegetable Extension agent at the University of Florida, offered some timely advice to growers faced with this situation.
“Harvest what you can, cover what you can, and apply freeze mitigation water where possible,” says Campbell. He adds that strawberry growers should prioritize the use of labor and address their greatest needs first. This can be particularly challenging as growers must harvest and lay cloth row covers at the same time.
Both McAvoy and Campbell stress the importance of keeping soils wet and raising water tables prior to temperatures hitting the freezing point. “When irrigating crops, growers must monitor relative humidity and dew point to ensure the initial spray’s evaporation does not unintentionally chill the plants,” explains Campbell. “Evaporation cools and freezing heats, so timing of sprinkler activation is critical. The plants are only protected if the water is forming ice, so on low humidity nights you must turn on sprinklers well before the freeze point to allow for initial evaporative cooling.”
McAvoy, however, cautioned against the use of overhead irrigation to ice down vegetable plants. “This is tricky as it requires large volumes of water and must be started before freezing temperatures are reached and maintained until ice melts,” he explains.
Running drip or micro-jet irrigation, however, can provide a warming effect. “Water coming from wells is typically at the same temperature as the yearly average ground temperature for the area,” says McAvoy.
Following any freeze mitigation, McAvoy suggests applying fungicides to assist recovery and hopefully prevent any colonization of wounded tissue by pathogens. He also encourages vegetable growers to take pictures and document the damage for insurance purposes. “Do not destroy the crop until given the ‘OK’ by the insurance rep,” he adds.