Fruit Grower’s Journal

Fruit growers have been racing down a fine line lately.  Fruit trees are early this year with blossom as much as 2 weeks ahead of normal in most orchards.  Apple flowers are not very hardy at bloom.  Temperatures below 29^oF spell trouble.

Frosts and near frosts the past several mornings have left many growers tired and worn.  They spend the nights checking temperatures and when temperatures approach the freezing point, they act.  If the farm has a wind machine, it it turned on and monitored continuously until the frosting action ends.  If sprinkler irrigation is being used, again, it is time to act.

Wind machines work by pulling warmer air from above down and using it to displace colder air settling in around trees.  A propeller whirls constantly and it rotates slowly around pushing cold air out in a large circle around the machine.  These machines take advantage of the fact that cold air is heavier than warm air. The coldest air will be nearest the ground in the lowest part of the orchard.

This pear survived frost during bloom, but a frost after fruit set severely damaged the developing fruit. Photo: W.G.Lord

Irrigation is more commonly used to protect strawberry blossoms, but works on apples too.  A continuous supply of water is applied once frosting conditions are near.  Ice will form, but as long as there is free water on the surface, temperatures will not drop below 32^oF. Water is applied continuously until all the ice has melted off the flowers.

Low temperatures promise to be more moderate over the next 7 to 10 days.  Let’s hope so.   Apple growers need the sleep and I want to eat perfect New Hampshire apples come fall!

Bill Lord, April 30, MMX