"We worry about this at this time of year," Gless Ranch vice president John Gless said.
Watching the crops closely begins when night falls.
"As the temperatures start dropping, we will throttle up the machine. Usually half throttle will be enough to get the temperatures up to a safe level," Gless said.
The machines Gless uses look like big fans. When combined with frost water distributed through their irrigation system, it keeps the trees warm and healthy.
"The temperature of the water is so much warmer than the air temperature. Some nights it is more effective than the wind machines. It will pick it up a few degrees. (The fans) just blow the warmer air onto the tree. It creates movement and creates more heat. It will pick it up three to four degrees," Gless said.
His company also has people monitor thermometers overnight to make sure the fruit stays warm enough.
Gless said the most vulnerable time of year for citrus crops is from mid-December to mid-January.