Can Corn Survive a Severe Frost?

Frost can damage corn plants. Depending on the severity of the frost and where the plant is in its growing season, frost can kill corn plants. In such cases, it makes sense for growers to replant in the hopes of having a decent crop come harvest time. Because there are significant expenses involved in replanting, this should be avoided if it looks like the damaged plants will survive.

Weather -elated damage to corn plants can result from frost or lethally low temperatures. Frost alone is not usually lethal to a corn plant during the early growth of the plant. However, lethally low temperatures, which occur at 28 degrees or colder, and can kill a corn plant at any stage of its growing season. Such weather conditions are usually a threat early in the growing season. But a late-season frost may have a greater impact on crop yield. Late in the season, a frost that lasts four to five hours or a temperature drop to 28 degrees for five to 10 minutes can kill corn plants.

The key part of the corn plant is its growing point, which is below ground until the plant reaches 8 to 10 inches in height. Because the growing point is underground, it is protected from early frosts. Even if the leaves above ground are severely damaged by frost, the growing point can still survive and the plant can recover. Later in the season, when this growing point is above ground, the plant can be more vulnerable to frost damage. The stalk and ear shank can usually survive a lighter frost, but a more severe frost or a frost lasting longer can damage these key parts of the plant, effectively killing the plant.

Early in the growing season, a short frost will likely not kill off young corn plants. However, more than one consecutive day of frost or a frost that lasts for several hours can pose a serious risk to the corn plants. Plants have a better chance of survival when a short frost event is followed by several days of temperate weather.

Since the growing point of the plants is below ground during the early stages of growth when frost damage is most likely to occur, ground conditions can play a big part in whether a plant will be able to survive. Soil is most likely to freeze when it is loose, recently tilled, coarse or has low moisture. Moist soil can help to insulate the plants against cold temperatures.

When the above-ground portions of a corn plant are damaged by frost, new growth can occur in about five to seven days if the plant remains viable. Growers should wait at least a week to see if there is new growth, before deciding to replant. If the plant is viable, the cotyledonary bud should look healthy and begin to grow. This is the bud that will appear at the center of the leaves. If no growth of the cotyledonary bud is observed, the plant will likely not survive.