Corn Planting Depth

It’s A Game of Inches

For those that farm, it’s a yearly routine to second guess where your planter is set for what seems like entirely too long. Ideally, there would be a “set it, and forget it” option for the whole season, but soil conditions and even equipment changes as the season progresses.

University Extension guidelines in the U.S. recommend planting corn 1.5 to 2.5 inches deep. Much like herbicide rate recommendations, deeper is recommended for more coarse textured soils and shallower for finer textured more poorly drained soils.

Corn sown too shallow can hamper the nodal root development. Poor root development leads to decreased nutrient and water uptake. Especially in a dry season, an issue known as rootless corn syndrome can occur. This condition typically ends up with plants falling over and struggling the entire season.

Exposing seedlings to an increased risk of herbicide residual is a real consideration, especially this year. Dry conditions throughout the summer of 2021 raises concern (depending on herbicides) as to whether the prior years’ herbicide program fully broke down. Herbicide carry-over is always a bigger concern on the lighter textured soils.

Uneven emergence is another downfall of planting too shallow. Seed out of the moisture band and sitting in dry dirt is far more likely with shallow planting. Compaction and variability in tillage only exaggerates this.

Planting too deep most commonly is an issue when temperatures are cool and/ or wet. Planting deeper can help protect the seed should the forecast turn cold/wet, but only if the conditions at that depth were suitable in the first place.

Crusting is a consideration with planting deeper. The longer time it takes for the seedling to emerge, the greater the risk of a crusting situation. More finely textured soils such as clay loams and silt clay loams are far more apt to have crusting issues.