Key Reminders for Planting Corn - Spring 2025

Planting Depth: Plant 1.75 to 2.25 inches deep. Planting less than 1.75 inches deep, depending on weather and soil conditions, increases the probability of the corn seed not germinating, due to cooler soil temperatures or fluctuations in moisture in the seed zone. (I prefer to be closer to 2 inches for planting depth, and this is after the soil has been compressed to simulate the soil and planting depth after a rain or when the soil settles.)

Corn plants take in 30% of their weight in water during the germination process. By not having the proper planting depth, you risk seeds not fully germinating or not having enough moisture to continue to grow. Another forgotten reason to plant 1.75 inches or deeper is that many herbicide labels state that to safely use that product, corn needs to be planted 1.5 inches or deeper, or injury may occur.

Soil Temperatures: Plant when soil temperatures are 50°F or more, or when air and soil temperatures will be increasing to that level or more. Corn can germinate with temperatures less than 50°F, however, germination is more consistent at 50°F or more. If soil temperatures are in the low 40°F or less, you can increase the incidence of imbibitional chilling injury or cold shock syndrome which can kill plants and, subsequently, reduce plant populations/harvestable ears. Cool wet soil increases the incidence of crown rot as well as seedling diseases.

Starter: I recommend utilizing a quality liquid starter and zinc to help the plant have an energy source (phosphorus in the starter) and the ability to help move nutrients and protect the germination process (zinc). It has been my experience that a quality starter and zinc helps the corn “pop up” out of the soil and have better early season growth. It is also my observation that this early season growth translates to earlier tasseling and more consistent pollination which, in most cases, leads to increased yields, better test weight and dry down.

Plant Populations: My typical recommendation is to plant 1000-1500 more seeds than is desired for a harvestable stand. Part of the reason is that not every seed will germinate, along with other factors such as:

Less than ideal planting seedbed
Hail/brittlesnap
Wildlife I.E. racoons, skunks, geese, turkeys, deer, grazing cattle and, in some southern states, wild hogs may eat seeds or seedlings
Seed and seedling diseases
Soil types

The ability to variable rate plant has changed how we handle some of these issues, and is a tool that provides a better Return on Investment than increasing the seeding rate across the entire field.

If you have questions or concerns regarding this please contact your Dairyland Seed Representative or Agronomist.