Should you replant?
The Minnesota agronomists say that is one of the most stressful questions that can be asked. “One of the most stressful and important decisions a farmer has to make is whether to replant when plant stands are reduced because of some kind of injury to the crop. The seven factors for evaluating whether to replant are
- the existing plant stand
- distribution of the plant stand
- calendar date
- weed situation
- seed availability of earlier maturing hybrids
- cost to replant
- yield potential of the existing crop.”
When considering replanting the crop, the first two factors to evaluate are the plant stand and the distribution of the plants remaining. Determine the number of live and healthy plants that exist. If hail caused the stand reduction, wait three to five days following the storm to allow the plants to begin to regrow. This gives time for some regrowth and, consequently, a better evaluation of whether the plants will survive. During this waiting time, growers can make all the necessary plans for replanting such as financial considerations, preparing the equipment, determining the availability of seed of early maturing, good-yielding hybrids and others.
When hail damages young corn plants, they usually regrow if the growing point is still healthy. Some plants that are severely damaged by hail may have difficulty regrowing. Plants with leaves loosely bound in the whorl usually grow or blow out, and continue with normal development.
The uniformity of the stand remaining is also important. Uniformly spaced plants produce more per plant, and more per acre, than do unevenly spaced plants. Large gaps in the stand can reduce grain yields by about 5% at plant populations between 14,000 and 28,000 plants/acre. Therefore, add 5% to the yield reduction for lower-than-optimum populations with large gaps (2 ft. or more) in the stand.
The rate at which corn recovers will influence its competitive ability with weeds and its sensitivity to various weed control practices. If the field to be replanted is especially weedy, a soil-applied herbicide may be needed on the second planting.
Leaf loss early in the growing season, particularly major amounts of leaf loss, is thought to set back the corn plant or delay the maturity. But, extensive research shows no appreciable delay in tassel emergence, silking date or kernel moisture content at harvest resulting from partial or complete leaf removal for plants between leaf stages 5 and 13.