As a follow-up to my previous post on Sunday (3/28) I wanted to discuss what we can expect from the cold temperatures tonight and tomorrow regarding recently planted and young corn.
The National Weather Service is now projecting the low for Blackville, SC to be 34 F, 32 F & 36 F over the next three days. With these temperatures, any seed planted within the last 24 to 36 hours could have the possibility of experiencing chilling injury when imbibition of water takes place. Depending on how cold the soil and the soil at planting depth gets will highly influence the fate of any seed germinating. Again, if soil temperatures do get cold enough (< 40 F) to cause injury, symptoms will likely result in swollen kernels that do not germinate or no radicle root or coleoptile growth after germination of the seed occurs.
If injury occurs after germination symptoms may include stunting, root death, and poor stands across the field.
For corn that was planted and has already emerged, injury can range from minor leaf injury to complete plant death depending on how cold it gets. Fortunately for corn, the growing point remains below the soil surface until approximately V5 (~12 inches tall). With that being said, corn can withstand some frost early in its development and be okay. Unless we have a killing frost, and air temperatures get to approximately 28 F or lower, corn that has already emerged and is up should be okay.
Overall, I think we are going to stay above 28 F across the state where corn is planted (good news). If injury or seedling death is suspected from cold temperatures, you should know within a week if the corn will recover or not.