By Darren Hefty

The ideal corn planting depth is and likely always will be 1.5” to 2.5”. Here’s why.

4 Root Systems of a Corn Plant:

  1. Radicle
  2. Seminal
  3. Nodal
  4. Brace

While the radicle and seminal roots develop below the corn seed, the nodal roots actually develop first above the seed. For this reason, the seed must be deep enough to keep the nodal roots under the soil surface, but that’s not the only consideration.

Corn Planting Depth Diagram

Above the seed, the first thing you’ll see is the mesocotyl. Its job is to push the coleoptile to the soil surface. The mesocotyl length will vary depending on how deep you plant the seed, but it is generally at least 3/4” long. At the base of the coleoptile is where the first of five rings of nodal roots will develop. The nodal roots will need at least 3/4” to grow. So adding 3/4 plus 3/4 equals 1.5”. That’s the minimum depth or nodal roots will grow above ground.

Why no deeper than 2.5”? It’s simple. The likelihood of problems is just too great. You’re at risk for crusting. It takes longer to emerge. The other big consideration is how much energy it takes to get out of the ground. Think about that one. The seed only contains a fixed amount of energy, and the root system really won’t start bringing in a lot of nutrients until V1-V2. If you use up all the seed’s energy before emergence, you’ve got a real problem.

Plant your corn safely in the 1.5” to 2.5” depth range this spring and avoid unnecessary stress on your plants.