Extension Column

Optimum soil temperatures for corn germination and plant progress begins at 50 degrees F. Soil temperatures lower than 50 F can cause corn seed to lay dormant, exposing the seed to disease and insect damage.

When corn seed is planted into soils that are too cold to allow adequate germination a condition called imbibitional chilling can occur. Seed imbibition is a two step process; water is absorbed by the seed and the seed swells. When seed swelling occurs, imbibition begins which activates enzymatic processes in the seed, including increased seed respiration and cell duplication.

In other words, germination. This germination activity results in seedling growth and finally emergence. Cold soils slow this process and can result in lower germination and delayed seedling growth, increasing potential seedling pest issues such as seedling disease problems. Other issues with delayed emergence include restricted seedling development which restricts nutrient uptake and damaged or aborted sprouting. Herbicide injury is also a factor with slow seedling growth as this condition exposes seedlings to an applied herbicide for longer periods of time.

Planting corn seed when soil temperatures and conditions are favorable provides the corn plant with the best chance for successful emergence which gives the corn crop the best start.

For current soil temperature information, access the Colorado CoAgMet system at: https://coagmet.colostate.edu/cgi-bin/monthly_coag.pl.