A Simple Explanation Of Frost Fighting

What a few days of frost fighting I’ve had!

I’ve been asked via email on quite a few occasions as to what is involved with the whole frost-fighting process.
So here goes; a simplified version so as not to bore you senseless; we have an overhead sprinkler system set up in the Orchard which is run by a tractor-powered pump located just below our irrigation dam.
At this time of year the immature fruit on the trees are highly sensitive to frost damage.
I have a frost alarm set up in my bedroom which alerts me when the temperature hits 2 degrees C.
This means it’s time to get up and patrol the Orchard and monitor the temperatures as there are temperature variations throughout the property.
If the temperature reaches around 0.4 degrees Celsius in the coldest area, I then crank up the pump and the sprinklers kick into action.

The water is sprayed on the trees and acts as an insulator when temperatures reach the freezing point of 0 degrees Celsius.
The fruit is protected by the process of the ice forming a “cocoon” around the fruit.
However it is vital the ice is constantly being formed otherwise the temperature of the fruit will rapidly drop and within 30 minutes serious tissue damage will occur, killing the fruit.
This is why the sprinklers are run until the air temperature is well above freezing .

If we don’t frost fight or if there is a delay in starting up the tractor then the frost will cause the cells of the fruit to crystalize and splinter and after the couple of days the tissue of the fruit will turn brown and die.

Not a very pleasant scenario for any Orchardist as that means you have lost your income.