Plant Corn By Soil Conditions and Temperature

After a long winter and the arrival of spring, many growers want to get into the field. However, planting too early can have a negative impact on yield. It is important to plant according to soil temperature and conditions and be aware of potential issues caused by cold, wet soils.

Corn requires a soil temperature of 50 °F to germinate and grow. Temperatures below the optimum can cause seeds to remain dormant and become more vulnerable to diseases, insects, and animal predators. Planting into cold and/or wet soils can lead to numerous problems.

In this region, corn is often planted before the optimum window in an attempt to get all the corn acres planted. Decreases in yield potential can occur when corn is planted after the optimum planting window, while early planted corn can have a higher yield potential. The Ohio Agronomy Guide – OSU Extension, identifies the ideal planting window for corn in Northern Ohio as April 15th through May 10th, while Southern Ohio is April 10th through May 10th.1 Due to the short ideal planting window, most growers plant some corn before and after the ideal planting dates. The long term forecast should also be considered when evaluating conditions for planting. Planting should be delayed if the soil conditions are not right. Ohio State University indicates that relative maturities should not be switched unless planting is delayed to late May.2

Table 1 lists the usual planting dates, in most years, based on 20 years of data and knowledge from industry specialists, reported by the USDA. The ‘Beginning Date’ designates when planting is approximately 5% complete, ‘Most Active’ designates when 15% to 85% of planting is complete, and ‘Ending Date’ designates when 95% of planting is complete.

  • Do not plant too shallow. Planting less than 1.25 inches deep can result in rootless corn or root lodging. Shallow planting can also increase the risk of injury from some soil-applied herbicides.
  • Do not plant deeper than necessary. When soil moisture is abundant, plant around 1.5 to 2 inches deep. When soil moisture is high, planting at depths of 2 to 3 inches can significantly delay emergence. If soil is dry and/or sandy, planting at 3 inches into moisture is less risky than planting shallow in anticipation of rain.

Planting when soil temperature and conditions are favorable is very important to give the crop the best chance of emerging properly and getting off to a good start. Waiting for good soil temperatures and conditions may help avoid chilling injury, disease, lack of oxygen to the seeds, and restricted plant growth, which can all lead to poor emergence. However, in some instances, such as a late spring frost, injury may be unavoidable. Although it is important to plant within the acceptable planting window for the region and crop, rushing to plant in cold, wet conditions can lead to yield reducing problems later.

Table 1. USDA corn planting dates in Ohio.3*
State Beginning Plant Date Most Active Plant Dates Ending Plant Date
Ohio April 18 April 24 - May 24 May 30
Source: Source: USDA-NASS. October 2010. Field crops usual planting and harvest dates.