Late Corn Planting in the Midsouth

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Corn planting has been delayed in many areas due to rainfall and unseasonably cool temperatures. However, it is important to remember that late-planted corn can still mature reasonably close to earlier planted corn in the Midsouth region.

Length of Growing Season. The late planting of a full-season corn product does not necessarily result in its maturity being greatly delayed. Research has demonstrated that as planting is delayed, the growing degree units (GDUs) required for an individual corn product’s maturity decreases. Corn generally requires 1.6 and 6.8 GDUs less for each day beyond May 1 to reach flowering and physiological maturity, respectively.1 Therefore, corn planted in late May compared to an optimum date may take 110 to 210 fewer GDUs to re​ach black layer.

It is important to also remember that later planted corn has a greater chance of being exposed to heat and drought stress during pollination. This risk can be managed by selecting corn products with heat and drought tolerance and early flowering characteristics.

There is Still Time. According to averages taken from the United States Department of Agriculture, corn planting season in the Midsouth is still underway. Planting dates vary across the region, refer to Table 1 for most active planting dates and end dates by state.

Table 1. United States Department of Agriculture Corn for Grain Usual Planting and Harvesting Dates.2
State Most Active End
Arkansas April 1 April 26 May 9
Louisiana March 19 - April 8 April 16
Mississippi March 24 - April 27 May 4
Tennessee April 5 - May 10 May 25


Impact of the Growing Season

Environmental conditions for the remainder of the growing season and availability of irrigation will make a difference:

  • Planting into wet soils can result in uneven planting depth and seedling establishment, poor root development, or sidewall compaction. Make good agronomic decisions and plant when fields are fit.
  • Insect protection, disease tolerance, and crop safety become even more important with later planted corn.
  • Even with delayed planting, it is still important to try to minimize the risk of adverse weather during critical growth stages by planting a package of products that range in GDU requirements to flowering as well as maturity.
  • Yield reduction associated with late-planted corn on dryland acres is typically more significant compared to irrigated corn.
  • Your local agronomist can provide recommendations for corn relative maturity groups and seeding rates that fit specific situations.

Source: 1Neild, R.E. and Newman, J.E. 1990. Growing Season Characteristics and Requirements in the Corn Belt. Purdue University Extension. National Corn Handbook, NCH-40.  2Corn for grain usual planting and harvesting dates. October 2010. United States Department of Agriculture. National Agricultural Statistics Service. 180404080116 04042019CRB

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