Source: Iowa State University

With a large percentage of Iowa's corn crop planted, cooler weather may and wide fluctuations in temperatures may inhibit the growth of the crop.

Cooler soil temperatures slow the germination process and predispose seedlings to fungal infection. We have also observed, or heard reports of, seedling growth problems in some parts of Iowa already this year, including:

  • Imbibitional chilling damage, which is the chilling effect seeds may experience when they imbibe, or absorb, water when soil temperatures are less than 55 degrees F for an extended time. 
  • Soil crusting due to wet soils at planting or heavy rains after planting reducing plant stands. Significant stand reductions lower yield potential. 
  • "Leafing out" underground. This occurs most often in crusted soils and also appears associated with imbibitional chilling.
  • Variable plant emergence and reduced plant population. Variable emergence and growth will reduce yield.

Original press release