Even the Sunshine State of Florida experiences winter colds. Low winter temperatures of 40 degrees Fahrenheit aren't uncommon in Jacksonville, Pensacola and Tallahassee; Tampa and Orlando regularly experience winter temperatures of 50 F. During freezes or cold spells, citrus trees can suffer and die. While certain types of trees are more cold hardy--and older trees more so than younger ones--all Florida citrus trees can be protected from frost damage with advance planning.
String Christmas lights through your citrus tree's branches late in fall in case of frost. During cold spells, plug the lights in overnight and leave them on until the temperature rises. This will protect the branches of your tree.
Cover the tree with burlap in the fall. While this is easier with small trees, large trees can be wrapped. Wind the burlap around the branches of your citrus, pinning the layers together with safety pins. When the canopy is covered, wind the burlap down to the base.
Burlap is breathable unlike plastic; the tree won't suffocate. Trees wrapped in lights and covered with burlap are well equipped to handle cold weather.
Place a portable space heater outside during cold periods. Plug an electric heater into an outdoor outlet or use a fuel-powered heater. Turn the heater on a low setting and oscillating mode. Aim the heater at the citrus tree. Leave the heater on all night and turn it off during the day.
Set up a sprinkler and connect it to your outdoor hose. Turn the sprinkler on before the temperatures drop below freezing. Leave the sprinkler running through the duration of the cold spell until temperature rise to 37 F. The water actually creates heat as it turns into ice; this keeps the tree warm enough to get through the cold spell. Do not use this method on trees in conjunction with any of the above methods; only use this on otherwise unprotected trees and never in conjunction with electricity or heat sources.