The past week brought driving rain, hail, frost and even some snow across Latham Country. Colder ambient air temperatures have led to colder soil temperatures, which are now below 50 degrees in many counties across the Upper Midwest.
A sustained soil temperature of 50+ degrees is needed for corn to germinate. Chilling injury can affect the corn plant very early during germination (just 1 to 2 days after planting) and cause stunting or total death of the root system so that the plant fails to emerge, says Latham’s agronomist Mark Grundmeier. Chilling can also take place after germination but before the V4 stage if soils temps drop into the low 40s.
With cold soil temperatures and the threat of chilling injury, there’s no need to rush into the fields. It’s only April 18, after all. Many prime planting days remain. Research by Iowa State University and the University of Nebraska – Lincoln shows that corn planting dates range from April 11 to May 13 for 100% yield potential. The last 5 days of April and the 1st week of May result in the highest yield potential for soybeans.