Cold and wet weather conditions have hindered corn planting during the month of March in Louisiana. In most years, a significant amount of corn is planted during this time. Planting date is a critical component in maximizing corn yield and profit. Therefore, corn growers in the Deep South are asking is the planting window for corn still open?

April 15 is the last date for getting the seed in the ground for maximum yield potential. Corn's yield potential when planted later than this date, may be reduced by abiotic factors that include high temperatures and less than optimum soil moisture during the pollination period.

Date of planting studies conducted in the mid-90s and in 2011-12 by Dr. Rick Mascagni, Research Agronomist at the Northeast Research Station supports and validates this recommendation.

The 2011-12 field experiments were conducted on a Commerce silt loam and a Sharkey clay at St. Joseph. For the 2011 study, planting dates on the Commerce were March 19, April 14, and May 16; planting dates for the Sharkey were March 19, April 14, and May 16. The 2012 planting dates for the both the Commerce and Sharkey trials were March 20, April 20, and May 18. The Sharkey trials were furrow irrigated in both years while the Commerce trials were not irrigated.

  • In both years, yields were the highest for the March planting and declined as planting were delayed.
  • On the Commerce soil, yields decreased 4% for the April planting and 41% for the May planting when compared to the March planting date.
  • On the irrigated Sharkey, there was a 16% and 63% yield decrease for the two later plantings when compared to the first planting date. Foliar disease pressure was not significant in any of the trials. However, fungal seed rots (primarily Diplodia and Fusarium) generally increased with the later dates. Insect pressure from corn earworms was the same across all planting dates.

Findings from these studies confirm that the planting window for corn is still open until around the middle of April. It appears that the reduced yield with the later plantings were probably due to abiotic stresses that include high temperatures and moisture stress at pollination