We should not expect yields of corn planted in the first or second week of April to be higher than those of corn planted the third or fourth week of April. We have had a few instances when corn planted in early April yielded less than corn planted later in April or first of May. This doesn’t happen often enough to rule out early planting, but it does mean the main reason to plant in early April is to get done by the first week in May and avoid late-planting yield loss. Another caution is to plant early only when seedbed conditions stay favorable if it rains or is still wet, growers should not try to get in the fields too soon. It typically requires about 110 to 120 growing degree days (GDD) for corn to emerge. With highs in the mid-60s and lows in the 40s to low 50s, we accumulate less than 10 GDD per day, so it can easily take two to three weeks for the crop to emerge. Typically this isn’t a problem however it is a long time and problems can develop that hinder emergence.
Early-planted corn should be watched carefully, especially when GDD accumulations pick up and the crop approaches emergence. Low soil temperatures are not the major risk factor that planted corn faces. Instead, heavy rainfall soon after planting, with seeds or seedlings dying from lack of oxygen, is the major cause of replanting. Chances of this happening are no higher for early than for later planting that depends more on soil moisture. While we hope that we won’t need to replant, one of the advantages of early planting is that if we need to replant it can be done early enough to avoid large yield loss from late replanting. Hopefully Mother Nature is good to us this year and we can start on time and finish on time. Just keep in mind it sometimes is beneficial to wait an extra day after a rain before getting back in the fields.
Thanks, Joel Wilhelmson