Early Corn Planting Key to High Yields

Research at the University of Missouri indicates the corn optimum planting date is from April 20 to May 10. However, with weather and many growers planting a large number of acres, growers will plant earlier than April 20. If so, research indicates that one should increase planting rates to compensate for plant loss.

Corn will not germinate below 50 degrees Fahrenheit but the seed will imbibe water. This can cause kernels to rot. Corn may take 18 to 21 days to emerge when soil temperatures are 50 to 55 degrees Fahrenheit. This longer germination time exposes seed to plant diseases and possible soil insects.

Often the soil conditions are an important indicator when to plant corn. If the soil moisture is appropriate, early planting before April 20 can be important especially for growers will large acres to plant. However, planting in wet soils and exposing corn to cold temperatures increase stand loss and may cause problems if the season turns hot and dry.

The goal should be to have all corn planted by May 10. Of course this depends on the number of days available for planting, acres that can be planted per day along with soil conditions. This may give you a guide of how soon you need to start. Only a portion of the days available able to do field work can be used to plant because of weather. Yield loss from delayed planting is greater than planting too early.

The average number of days available for field work from mid-April to first week of May is 3.1 to 3.2 per week in Northwest Missouri. From the second week of May to the end of May, the average numbers of days for field work increase to 3.6 per week. The data is from Guide 362 "Days Suitable for Fieldwork in Missouri."

For more information, contact Wayne Flanary at 660466-3724 or Heather Benedict at 660-425-6434, Regional Agronomists, University of Missouri Extension.