Let’s start with how frost is formed. There are two kinds of frost that occur, Advection Frost (winter freeze) and Radiational Frost.

Advection Frost or winter freeze as it is commonly known, is formed when very cold winds pass over crops and leave tiny ice crystals behind. This can happen day or night however this is more common in colder climates at higher latitudes.  

Radiational Frost is referred to as frost in South Africa. It is formed when we experience warm days and cold nights. The heat from the day is absorbed into the ground and when the air cools at night, heat radiates from the ground and rises. As this happens there is a rapid drop in temperature near the surface and the very low temperature allows frost to form on your trees and fruit. This is turn dehydrates the crops by pulling moisture from the surface and causes permanent damage.  

The heat that radiates from the ground doesn’t just disappear but gets trapped by the colder air above it and forms something known as the inversion layer. This is normally located between 8m and 20m above the ground.  

Orchard Fans pull the warmer air from the inversion layer and replace the colder ground air flattening the temperature gradient and preventing frost from forming. The fans are slightly angled to push the warmer air towards the ground. They are also able to rotate 360° on their own axis allowing them to protect a wider area. Our fans should achieve circular coverage between 5.5 to 7 hectors in most cases.