Fruit farmers have long used everything from propane heaters to sprinklers and fans to protect their produce from devastating late freezes.
As handy as they are, it's hard to know when to deploy these systems. Ideally, farmers need frost-preventive irrigation systems running before a hard freeze affects their fruit, but turning them on too early wastes water, fuel and electricity. Turning them on too late can lead to crop loss.
Many fruit trees have already bloomed and, with this week's temperatures projected to drop below freezing at night, a new tactic for calculating dew point could be extremely valuable.
Atmospheric scientists at the University of Georgia have recently developed a simplified set of equations to help farmers who use irrigation for frost protection predict the best time to turn on their systems, maximizing crop protection and minimizing wasted water and power. They published their findings recently in the Bulletin of the American Meteorological Society.
"This kind of information is important, especially this year, because everything is blooming so early," said Pam Knox, agricultural climatologist with UGA Cooperative Extension. "Georgia's blueberry farmers could see a huge loss if we have a hard freeze."
A table based on the new calculations is now available on Knox's blog at blog.extension.uga.edu/climate, allowing farmers to easily determine when to start their irrigation for frost protection based on dew point temperature and the calculations described in the paper.