Planting Depth: What is the right number?

  • May 13
    Chuck Belanger
    Planting Depth: What is the right number? By Chuck Belanger on May 13, 2014
    Categories: Grain Corn, Silage Corn, Soybean

    Wet weather has kept planters out of fields and has tested everyone’s patience. Growers will be tempted to reduce the planting depth when seeding into moist soil conditions. I want to touch on the importance of maintaining the proper seeding depth, even when planting in these conditions.

    When writing this blog, I referenced two papers. One was written by OMAFRA and the other by Iowa State University. The articles vary slightly, but both agree that a corn planting depth of less than 1.5 inches is NOT good.  According to OMAFRA, optimum corn planting depth is 1.5 inches, whereas Iowa State advises that the best results occur when corn seed is placed at 2 inches. Anything shallower than 1.5 inches may result in poor nodal and brace root development, and a less than favourable position of the growing point that may predispose the corn crop to frost or herbicide injury.  Below is a photo posted on Twitter from Bob Neilson (@thecornprophet). Note the root development at the different planting depths and the growth of the plants 26 days after planting.

    Optimum planting depth of soybeans is 1.5 inches.  There may be occasions when soil moisture is high that the soybean planting depth can be raised to 1 inch.  A germinating soybean has a high demand for moisture.  A 1 inch planting depth does not always guarantee adequate moisture for germination. Moisture in the spring is usually ample at 1.5 inches, but deeper planting depths may be required to plant into moisture. Never plant soybean seed deeper than 2.5 inches.  If moisture is deeper than 2.5 inches (especially on clay soils), then you may want to wait out the weather and hope for moisture.

    The moral of the story here is to take the time and get off the tractor to check your planting depth. Ensure that you are planting your corn at 1.5 to 2 inches and your soybeans at 1.5 inches deep - and into moisture. Your crop and your wallet will thank you at harvest.

    Chuck Belanger, Maizex Seeds Yield Specialist, North Essex and South Chatham-Kent Counties
    Twitter: @sprayman63