Observations of the February 2012 Freeze and Its Effect on Commercial Blueberry Plantings

Abstract

Producers of commercial southern highbush blueberries often have to take precautions to protect their crop from freezing conditions encountered during the growing season. Cultivars that produce fruit during the optimum market window for Florida producers, ranging from late March to early May, are often subjected to damaging temperatures to the expanding floral buds, flowers, and developing fruit. During early February in 2012, a two-night freeze caused significant damage in fields in north and central Florida. Normally, freezes during this time frame do not pose a significant threat to commercial fields, unless temperatures are 20 °F or lower. This is because the floral buds generally have not expanded to the point where temperatures in the mid 20s to the freezing mark would cause damage. Due to warmer than average temperatures, commercial blueberry crops had progressed to the point where significant bloom and developing fruit were present. Most growers consider 32 °F to be the critical temperature to freeze protect developing fruit. Since many growers in the region expected temperatures below 32 °F, they planned to utilize overhead irrigation to protect their crop. After the two nights of freeze, significant cold damage was reported. Much of the damage was associated with irrigation system failure or inadequate coverage. Growers who took wet bulb temperature into consideration as the trigger to begin applying overhead water typically fared better in the freeze.