Fruit bud damage from cold temperatures

With the freeze warning and cold nights and morning we have seen over the last few weeks, fruit growers often wonder at what temperature fruit buds are killed.

The following will give you some guidelines but remember that the actual damage is going to be influenced by the weather before the temperature drops.

An extended warm spell before the cold snap may result in more damage due to a loss in cold hardiness.

Apple; Stage

10% Kill (°F) 90% Kill (°F)

Silver tip    15 2

Green tip     18  10

Half-inch green  23 15

Tight cluster    27  21

Pink   28 25

Bloom   28 15

Petal fall   28 25

Fruit set   28  25

Pear; Stage

     10% Kill (°F)    90% Kill (°F)

Swollen bud  15 1

Bud burst    20 7

Green cluster  26 15

White bud  26  22

Bloom  28  23

Petal fall  28  24

Fruit set 28  24

Peach; Stage

    10% Kill (°F)    90% Kill (°F)

Swollen bud  18 2

Half-inch green 23 5

Pink 25  18

Bloom 27  24

Petal fall  28  25

Fruit set  28  25

Tart Cherry; Stage

  10% Kill (°F)    90% Kill (°F)

Bud burst  17 5

Green tip 25  14

Tight cluster  26  17

Swollen bud 27 24

Bloom  28 25

Petal fall     28  25

Fruit set  28  25

Plum and Prune; Stage

     10% Kill (°F)    90% Kill (°F)

Swollen bud  14 1

Bud burst      18 3

Green cluster  26  16

White bud 26  21

Bloom 27  23

Petal fall     28  23

Fruit set  28 25

Apricot; Stage

     10% Kill (°F)    90% Kill (°F)

First white  24 14

First bloom 25 19

Full bloom     27  22

In the shuck   27 24

Green fruit  28  25

To determine whether a fruit bud is alive or dead, use a sharp knife or a single edge razor blade and cut buds in half.

Remove buds from the tree and make the cut starting at the base and cutting upward. If the fruit pistil in the center is greenish white to cream color, no damage has been done.

However, if the fruit pistil is dark brown or black, it has been killed. Cut a number of buds to find a percentage killed.

Some loss of buds is actually beneficial for peaches and apples. These trees often produce far too much fruit and require thinning for top quality.

As a rule, we want an apple or peach an average of every six to eight inches on a branch. We can often achieve this with only 10% of the original buds developing fruit.

For more information on growing fruit trees, contact the Ford County Extension Office or visit us online at www.ford.ksu.edu.