Planting Corn - When Should I Start?

Phil Swantek, Western Product Agronomist
March 30, 2021

Each year, it seems like the corn crop in the Midwest gets planted earlier and earlier. I’ve heard many at the coffee shop joke about how a NASCAR pit crew is rivaled only by a farmer who just saw his neighbor pull the planter out of the shed. While these jokes may be partially true, producers should be cautious when planting into cold soils. A producer has one chance to plant each year and must live with the results for the remainder of the growing season. Here are a few things to consider when choosing to start planting:

When corn is planted, it enters a critical 48-hour window. During these 48 hours the seed uptakes a small amount of water. If this water is too cold, plants can experience imbibitional chilling (or leaf out underground); this will have a profound effect on emergence and uniformity. The specific temperature of imbibed water that causes corn yield loss is debated but thought to be in the mid to low 40s. It’s best to plant during a period when the soil temperature at planting depth isn’t anticipated to drop below the critical temperature of 50 degrees.

During planting season, producers feel the stress of getting their acres planted in a small timeframe. However, this timeframe may be larger than many think. Iowa data from 2017 shows that there is a window of time to plant where yields don’t vary greatly, and this window starts to close after the middle of May (Figure 2).

If planting early: consider a hybrid with a greater stress emergence score. These scores can be found in the Hoegemeyer Seed Guide. Growers should also consider their local planting date restriction to qualify for federal replant payments. In the Western Corn Belt, these dates range from late March to late April.

Figure 1: Corn Seedling Leafing Out Underground, Roger Elmore ISU


Figure 2: Abendroth et al, 2017

Please contact your local Hoegemeyer agronomist with any questions.