“Mother nature teased us back in April with some warm, sunny 70-degree days,” said Mike Slater, Federated agronomy sales rep at the Isanti location, and then came more cold nights and rains in late April and early May, highlighting the need to choose the right hybrids.
“Hybrids with better emergence scores typically handle wet and cold soils better,” said Slater. Choose those hybrids unless temperatures have reached ideal temperatures.
“Soil temperatures need to be at least 50o F for corn seeds to germinate, and before the May cold snap came, fields in Isanti were only at 47o F,” said Slater.
He explained the issue of colder soils: “Corn will absorb moisture into the seed within the first 24 hours of being planted and if those temperatures are too low the seed can experience cold shock. Imbibitional chilling can occur from absorbing water when the soil temperature is below 55o F.”
Imbibitional chilling results in seeds that rupture or seedlings that cork screw underground, which can lead to poor and uneven emergence, as well as leafing out underground. (Various photos and descriptions of this problem are available here.)
Discuss any planting concerns with your Federated Agronomist.