Much of the Upper Midwest experienced frost damage to crops over Mother’s Day weekend, which is causing concern among farmers in many areas. The main concern is with the corn that was planted in mid-April, and was fully emerged with two to four leaves. The leaves on the emerged corn were severely damaged by temperatures that dropped to 30° F or lower in many areas of southern and central Minnesota on the morning of May 9. The most severely affected cornfields, or portions of fields, are likely to be on sandier or peat-type soils, and in fields that were also planted to corn in 2009. Areas near road ditches, grass waterways or other non-tillable acres, as well as very dry soils, are more likely have more severe frost damage. Most of the region had adequate rainfall in recent weeks to fully moisten the topsoil, which may help alleviate some of the widespread frost damage.
Fortunately, the growing point on corn is below the soil surface until the corn is 8-10 in. tall, and should still be protected from serious frost damage. The corn plant should start to exhibit new surface growth in about five to seven days under normal conditions. Producers are encouraged to wait at least a week, or longer, to allow the corn to recover before making any replant decisions, and to rely on the assistance of a crop consultant or agronomist before finalizing replant decisions.