i am studying a bit on orange trees and cultivation and came across this and thought it could get your minds moving. maybe its common knowledge, remember im an indoor gardener.
Oranges are sensitive to frost, and a common treatment to prevent frost damage when sub-freezing temperatures are expected is to spray the trees with water, since as long as unfrozen water is turning to ice on the trees' branches, the ice that has formed stays just at the freezing point, giving protection even if air temperatures have dropped far lower.[57]
Another strategy to prevent freezing of orange crops and trees is burning fuel oil in smudge pots (also known as a choofa or orchard heater). These burn with a great deal of particulate emission. Condensation of water vapor on particulate soot prevents condensation on plants and raises air temperature very slightly. Smudge pots were first developed after a disastrous freeze in Southern California in January 1913 wiped out a whole crop.[58]