Watch the Conditions not the Calendar When Planting Corn

Mud collecting on the closing wheels is a good indicator that the soil is too wet to plant. 

Chad Lee, University of Kentucky

Chad.Lee@uky.edu

Corn planting in 2022 is off pace from the five-year average for Kentucky with only 6% planted on the April 17 report. The calendar says we could have started planting corn April 1 in western Kentucky and April 15 in central and eastern Kentucky. The calendar suggests that we are behind. The weather and soil conditions suggest we are not.

Corn planted into cold, wet soils will have a delayed emergence and greater chances for uneven emergence, reduced emergence, insect and slug feeding, and seedling diseases. Corn emergence needs about 115 Growing Degree Days (GDD’s) accumulated. Warmer soils accumulate those GDD’s faster and result in more uniform emergence.

While most guides suggest that corn planting can begin when soil temperatures are 50 F, corn needs soil temperatures to average about 61-62 F (about 11-12 GDD’s per day) to emerge within 10 days of planting. Dropping the day and night temperatures from 77 and 59 F (18 GDD’s per day) to 68 and 50 F (9 GDD’s per day) delayed corn emergence by 10 days.

Farmers in Kentucky are fast at planting corn. A small set of data from Kentucky farmers a few years ago said that farmers plant corn on an average of 11 days regardless of farm size. Once the soils become favorable, most farmers will be able to plant quickly.

Sources:

Egli, D.B. and M. Rucker. 2012. Seed vigor and uniformity of emergence of corn seedlings. Crop Science. 52: 2774-2782.

Nielsen, R.L. (Bob), 2021. Soil Temperature & Corn Emergence. Corny News Network. April 12. http://www.kingcorn.org/news/articles_21/SoilTempEmergence-0412.html

USDA-NASS. 2022. USDA NASS Kentucky Crop Progress and Condition Reports. https://www.nass.usda.gov/Statistics_by_State/Kentucky/Publications/Crop_Progress_&_Condition/index.php