Frost Injury in Grapes
Bruce Bordelon, Extension Specialist, Department of Horticulture
and Landscape Architecture, Purdue University
Grapes are very sensitive to frost damage and there
have been several instances of light frost across the region this
spring. Damage is showing up in commercial plantings and some home
gardens. Frost damage often gets misidentified as herbicide injury
because other plants may not show typical signs of freeze injury.
Grapes are more sensitive than many other plants.
The tolerance of grape tissue to cold temperatures is relative
to their stage of growth. A bud that is just swelling can tolerate
temperatures in the low 20s with little damage. But as soon as
the bud has broken and the leaves unfold, the tissue is sensitive
to temperatures of 28-30°F. Varieties may also vary in their response
to freezing temperatures.
Damage usually shows up as wilted shoot tips and brown leaves
(See Picture 1). When temperatures are cold enough, all shoot tissue
is completely killed (See Picture 2). However, in many cases temperatures
are just at the lethal point and the shoot may not be completely
killed. Some leaves may turn brown and dry out, but older leaves
may remain alive and display a pattern of angular flecking with
sectors of yellow, white and green (See Picture 3). It is not unusual
to see healthy, undamaged shoots next to damaged ones (See Picture
In most cases the vines will recover as secondary
buds at the base of the damaged shoot will break and produce
healthy shoots for this growing season (See Picture 5). These
shoots are seldom as fruitful as the original primary shoots,
so fruit yields will be greatly reduced this year.