Temperatures in the low to mid 20’s last week have many producers concerned with the status of the wheat crop. The best thing producers can do is to wait a few days before evaluating the damage. It takes four to five days of warm weather before the freeze damage becomes visible.
There are a number of key factors in determining freeze damage: the stage of development of the wheat, the density of the stand and condition of the plants, the amount of residue on the soil surface, the extent and duration of low temperatures, temperature gradients within the field, soil moisture, and the wind speed.
After several days, producers should split open some stems and check the developing head. If the head is green or light greenish in color and seems firm, it is probably fine. If the head is yellowish and mushy, it may have freeze injury.
If a field of wheat is giving off the aroma of silage, that indicates that leaves have been damaged. Damaged leaves will likely turn black within a few days, then become bleached.
Plants that had ice in the stems below the lowest node, pose a good chance of resulting in stem injury, but not always. Stem injury can be determined by looking for crimped and damaged stems. Flag those areas, and monitor them to see if the leaves continue to emerge as the tiller grows. If they do, then they likely do not have injury. If they don’t or if the leaves emerge discolored, or if the plant lodges, then it likely has freeze damage.
Tillers damaged during early jointing may stop growing so the head will never emerge. In the boot stage, the heads will go ahead and emerge even if they are severely freeze damaged. However, the head may be partially damaged or completely dead.
Producers are encouraged to talk with their crop insurance advisers prior to making any decisions regarding terminating the crop. Producers can stop by the McPherson Extension office and request the publication Spring Freeze Injury to Wheat for more information.
Jonie James is a McPherson County Extension agent for agriculture.