Frost, Jack Frost.

Parts of Kansas and much of the Midwest are forecasted to have at or near freezing temperatures tonight and over the weekend. In northeast Kansas emerged corn is in the early V-stages and emerged soybeans are cotyledon stage to 1st and 2nd trifoliate. What do the anticipated cold temperatures mean for emerged and emerging crops?Frost damage that occurs prior V5 typically has limited impact on corn yield as the growing point is still sheltered below the soil surface. Temperatures near or below 32ºF can cause visual injury to corn resulting in water-soaked, silvered, or browned leaves. Temperatures near or below 28ºF increase the risk of more serious damage to corn plants even prior to V5 as cool temperatures may penetrate the soil and reach the growing point. Risk of damage to the growing point increases on drier and/or coarser soils.Freezing temperatures can also impact spiking corn. If the coleoptile, or the top of the spike, freezes emergence may be stalled and plants may begin to leaf out underground.Temperatures 28ºF to 32ºF are more perilous for young soybeans than for young corn. While a corn plant's growing point remains under the soil surface for its early V-stages, a soybean's growing point is fully exposed at the top of the soybean stem. Emerging and cotyledon stage soybeans are at greatest risk of fatality if the apical, or top of the plant, growing point freezes. More advanced soybeans with unifoliate or trifoliate leaves are less likely to fully succumb to frost damage. While the uppermost growing point may die as a result of cold damage, soybean plants can continue growth at unharmed axillary, or additional, growing points.Symptoms of frost damage typically become visible one to two days after the freeze event. Rule of thumb is to wait three to five days after a freeze to assess injury to crop stands. We can't control the weather, but we do know who to blame—Frost, Jack Frost.