Assessing Freeze Injury to Wheat

Published: May 16, 2014 | Updated: May 1, 2026

Assessing Freeze Injury to Wheat

Authored By: Robert Klein - Emeritus Extension Professor, Cody Creech - Dryland Cropping Systems Specialist, Nicolás Cafaro La Menza – Cropping Systems Specialist, Department of Agronomy and Horticulture, Al Dutcher - Former Associate Nebraska State Climatologist, Amanda Easterly - Research Associate Professor, Karen DeBoer - Former Extension Educator, Stephen Wegulo - Extension Plant Pathologist

Updated By: Cody Creech - Dryland Cropping Systems Specialist, Amanda Easterly - Research Associate Professor, Stephen Wegulo - Extension Plant Pathologist, Jenny Brhel - Extension Educator, Ruby Collins - Extension Educator, Samantha Daniel - Extension Educator, Eric Hunt - Agricultural Meteorology and Climate Resilience Extension Educator, Gary Stone - Extension Educator, John Thomas - Crops Extension Educator, David Wangila - Extension Educator, Todd Whitney - Extension Educator, Vinicius Zuppa - Assistant Extension Educator

Close-up of a hand holding a green leaf with white streaks; dry, yellowing grass in the background.

With freeze events hitting during critical growth stages, Nebraska growers are being urged to closely assess winter wheat fields before making management decisions.

Ruby Collins/Nebraska Extension

Nebraska winter wheat continues to face significant challenges as the crop moves into May. Poor condition ratings have been reported across much of the state, and multiple sub-freezing events occurred over the past two weeks, with the chance for more freeze events in the days to come. 

According to the USDA National Agricultural Statistics Service (NASS) crop progress and condition report for the week ending April 26, 2026, Nebraska winter wheat was rated 21% very poor, 44% poor, 23% fair, 12% good and 0% excellent. This places 65% of the crop in the poor to very poor categories entering the latter part of spring as the crop moves into heading. Drought stress remains the major contributing factor, with both topsoil and subsoil moisture deficient across western and central Nebraska.

In addition to moisture stress, wheat fields have been exposed to damaging cold temperatures. A freeze warning was issued for much of Nebraska ahead of the morning of April 18, with forecast lows ranging from 20 to 25°F across wheat growing regions. Another significant freezing event occurred the morning of April 29. 

These temperatures, combined with the four- to eight-hour duration they were present, are well within the range known to cause injury to wheat, depending on growth stage and duration of exposure (Figure 1). Wheat that has jointed becomes more vulnerable, as the developing growing point is elevated above the soil surface and can be damaged at temperatures near 24°F if exposure lasts two hours or more.

effects of freeze at various growth stages
Figure 1. How freezing temperatures injure wheat at various growth stages. (Graph adapted from A.W. Pauli for Nebraska Extension NebGuide EC132, "Freeze Injury to Nebraska Wheat."

Unique winter weather patterns in the 2026 crop — including a very mild winter and little snow cover — have impacted winter wheat development. As a result, wheat may be somewhat ahead of or behind normal expectations this year depending on when it was planted and fall growth. At the time of the first freeze this year, much of Nebraska’s winter wheat ranged from jointing to early boot. Some wheat is transitioning from boot to early heading this week. 

Potential for injury increases as the wheat continues to develop. Previous significant freeze events happened in 2020 and 2012. In 2012, winter wheat was as much as two weeks ahead of normal growth stage and in one county, winter wheat was largely a total loss from a late freeze on May 9-10. The growth stage in 2020 was more typical, and impacts from the freezes were more mixed.

It takes several warm days (a week or more, depending on temperatures) after a freeze before an accurate determination of injury can be made, and each new freezing event poses additional risks that may take time to become apparent. Producers are encouraged not to rush management decisions following a freeze event. 

Accurate assessment should include splitting stems to inspect the growing point, as well as overall scouting of the fields. Healthy growing points and immature heads will appear firm and yellow-green/translucent, while damaged tissue will appear water-soaked, white or brown, with a squishy texture. Leaf yellowing alone is not always a reliable indicator of head survival and may look similar to leaf response to other stresses (Figure 2). Table 1 outlines common symptoms and yield impacts by wheat growth stage.

Table 1. Temperatures that cause injury to wheat at spring growth stages and symptoms and yield effect of spring freeze injury.

Growth
Stage

Approximate
Injurious
Temperature
(Two Hours)

Primary Symptoms

Yield Effect

Tillering

12°F (-11°C)

Leaf chlorosis; burning of leaf tips; silage odor; blue cast to fields

Slight to moderate

Jointing

24°F (-4°C)

Death of growing point; leaf yellowing or burning; lesions, splitting or bending of lower stem; odor

Moderate to severe

Boot

28°F (-2°C)

Floret sterility; head trapped in boot; damage to lower stem; leaf discoloration; odor

Moderate to severe

Heading

30°F (-1°C)

Floret sterility; white awns or white heads; damage to lower stem; leaf discoloration

Severe

Flowering

28°F (-1°C)

Floret sterility; white awns or white heads; damage to lower stem; leaf discoloration

Severe

Milk

28°F (-2°C)

White awns or white heads; damage to lower stems; leaf discoloration; shrunken, roughened or discolored kernels

Moderate to severe

Dough

 28°F (-2°C)

Shriveled, discolored kernels; poor germination

Slight to moderate

 

Wheat stalks showing signs of discoloration in a sunny field.
Figure 2. Burned and yellowing leaf tips are common spring freeze symptoms at the tillering stage but can also arise from other stresses, including drought and herbicide/fertilizer applications.

Field variability is common following freeze events. Factors such as soil moisture, stand density, residue cover and landscape position influence injury risk, with thinner stands often showing greater damage. In some cases, secondary tillers may survive and partially compensate for yield loss. Remember that temperatures in low-lying areas are even lower and may show more pronounced impacts from freezing. 

Nebraska Extension NebGuide EC132, “Freeze Injury to Nebraska Wheat” can be a helpful resource when examining fields and provides additional photos and descriptions of impacts by growth stage.

As conditions evolve and impacts from the most recent freeze events become apparent, producers should continue to monitor fields and coordinate with crop insurance providers before making decisions related to crop termination. While the 2026 wheat crop faces multiple and notable challenges, it will take time to determine the extent to which the crop may recover and wheat residue provides benefits to subsequent crops. Growers can reach out to their local extension educators, Cody Creech, University of Nebraska-Lincoln (UNL) dryland cropping systems specialist, or Amanda Easterly, UNL research associate professor, with additional questions or to examine samples.

Regional Impacts 

Green plant stems, some intact and others damaged, arranged on a white surface.
Split stems from Cheyenne County-High Plains Ag Lab showing mix of heads that seem unaffected (left) and close up of head in boot stage showing yellowing and necrosis (right). Photo and sample: Vini Zuppa/Nebraska Extension
Three green plant stems with varying levels of damage, displaying discoloration and browning.
Split stems from southern Cheyenne County. Panels a and b were planted into corn fallow and had lower stand and freeze damage, whereas panel b is the same variety with possible leaf impacts but heads unaffected coming from a field of millet fallow. Photo and sample: Vini Zuppa/Nebraska Extension
Two green grass stems with seed heads, brown leaves at the base, on a white surface.
Split stems from Deuel County showing heads that seem unaffected by the first freeze but may not exhibit symptoms from April 29 yet. Photo and sample: Vini Zuppa/Nebraska Extension
Green wheat plants with slender leaves and developing grains on stems against a white background.
Split stems from irrigated field in Box Butte County that show little to no freeze damage at this point, though other reports from growers indicate that early maturing varieties and dryland fields are already showing head discoloration. Sample: John Thomas/Nebraska Extension; Photo: Vini Zuppa/Nebraska Extension.
Dry soil with sparse green grass and yellowing plants scattered across the ground.
Wheat field in western Banner County showing what may be freeze damage and/or drought stress but is difficult to determine yet. Photo: Gary Stone/Nebraska Extension
Green wheat stems with leaves and developing spikes laid on a white surface.
Split stems from Morrill County with some freeze-impacted leaf tips, but little head damage at this point. Sample: John Thomas/Nebraska Extension; Photo: Vini Zuppa/Nebraska Extension
Tall green grass stems and leaves on a plain white background.
Split stems from Sheridan County appearing to show early head damage from frost. Sample: John Thomas/Nebraska Extension; Photo: Vini Zuppa/Nebraska Extension
Green and yellow crops stretch across a large field under a clear blue sky.
Wheat field near Hebron in Thayer County with freeze damage potentially attributed to strips of high residue within the field versus strips without as much residue that had reduced cooling effects. Photo: David Wangila
Close-up of a hand holding a green leaf with white streaks; dry, yellowing grass in the background.
Close-up photo of freeze damage on leaves in Red Willow County (left). Surrounding field shows significant browning of leaves (right) from the tips on all tillers. Freeze damage can sometimes be differentiated from burning due to drought that is more often localized near the crown versus here where it is seen more uniformly. Photos: Ruby Collins
Close-up of wheat stems with brown spots next to a vast wheat field under a clear sky.
Wheat showing necrotic nodes and wilted leaves from Fillmore County (left) and surrounding field (right). Node and stem necrosis were exacerbated by significant drought stress and shallow rooting depth when planted after soybeans. Photos: Jenny Brhel
Nebraska map with certain counties highlighted in red.
Figure 3. Extension educators across Nebraska have been scouting wheat fields and consulting with growers. The map highlights counties with submitted photos. Growers are encouraged to reach out to their local water and cropping systems extension educators to share updates.

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