By Greg Roth
Professor of Agronomy
Some parts of the state experienced frost on Saturday morning this weekend, causing some concern. After 85 degree temperatures earlier in the month, I thought this threat might be past for the year but apparently that was not the case.
Corn and soybeans are my main concern although wheat and barley that were heading could be affected as well. Locally, temperature reached about 29 degrees in some of the low spots near Rock Springs, with the lowest temperatures occurring near sunrise. Frost injury seemed spotty, in some low lying fields, north slopes and on some larger plants.
Corn in most areas was in the 2-3 leaf stage in the region. A couple of large fields in the V4 stage were nearly completely burned back. I suspect that these plants will rapidly regrow with the warm temperatures forecast for this week. I would plan on evaluating frost damaged fields later in the week for signs of recovery. Occasionally frost damage with lethal temperatures or larger plants will cause stand reductions, so don’t assume complete recovery without some evaluation.
Soybeans can tolerate lower temperatures (about 28F) and longer period of low temperatures than corn. Our frost events seemed to be short in nature, and temperatures only declined to about 30 degrees F so I am suspecting good survival from early planted emerged soybeans. Soybeans can also have multiple growing points that they can regenerate from. Plan to assess soybeans in about a week for injury and survivability. This factsheet from Purdue provides some good pictures of injury symptoms.
Frost Damaged Corn
Frost Damaged Corn Close-Up