IF you are watching the weather forecast for the state, it will get much colder over the next few days. Just how cold remains to be seen. When it comes to our corn crop, should I be concerned? First, I will point you to Dr. Eric Prostko’s blog post, https://ugaweedscience.blogspot.com/ , regarding the potential spraying of corn over the next few days for those have corn from emerging to V-6. I strongly encourage you to proceed with caution and concur with Dr. Prostko regarding potential injury from herbicide applications during cold weather. I’ve seen damage over the years and it can be quite frustrating. He reminds the reader that “ The good news is that the field corn recovered from this injury and final yields were NOT reduced by the 1X rate. “. I will say this, there is always a first time for everything so please heed his warning.
Overall, corn growers are still trying to get their planned corn crop in the ground, particularly in the southern half of the state and cold, rainy conditions continue to interrupt that process. Currently, we have corn from just emerging to the V6 + stage. Fortunately, we still have time in the southern half to get the crop established and definitely in the Upper Coastal Plains and Piedmont. Growers in the northern portions of the state are still in good shape except land preparations have been slowed by the wet conditions. So, what do we do over the next several days?
Do we continue planting or stop and wait till the 2-inch soil temperatures rise back to current levels? Should we worry about frost damage? Temperatures according to the Weather Channel will dip tomorrow and Thursday as low as 350 in the south to 240 in the north, and then rise through the weekend. For those who like to be exact, well, these are estimations.
At the expected low temperatures, 2-inch soil temperatures will fall and could present a problem particularly with fresh rainfall over the state. That can spell trouble with newly planted fields. At first, I thought the temps would not drop so low but the forecast has changed over the last few hours. IF you have just planted, corn seed imbibing cold water can result in injury to seedling structures. It can rupture cell membranes, delay growth, and reduce your stands. Cold, wet conditions definitely will affect the soil temperatures and drop them from where they are today… I would not be surprised to see a 10-150 drop over the next two days, easily. It can affect your overall stand establishment but you can manage it over the next few weeks to minimize that impact.
Corn plants that are just emerging to V-2 can suffer some frost damage but will recover with warming temperatures. The degree of damage will depend on where you are and how small or advanced your growth is at the time of exposure. In most cases, it is cosmetic and will not lead to yield damage. Depending on the temperature and duration of a frost, you are likely see some “silver leaf” abrasion particularly on older corn. Our warm soil temperatures can mitigate some of the impact. If the temperatures drop below freezing, leaf loss will occur to a good portion of the above ground tissue. Corn that is less than a V-4 stage, can recover quickly as the growing point is still below the soil surface. Older corn may experience more difficulty. Hopefully, the wind will not be a significant factor as it can cause the dead tissue of older corn to wrap around the exposed stalk and interfere with the undamaged tissue from pushing through damaged whorl.
You may very well see some hybrid differences in recovery due to the differences in stress tolerances. These temperatures will reduce water uptake and cause stomatal closure. All of this diminishes the respiration and slows carbohydrate production. Returning to normal growth can vary some between hybrids. Also, differences in soils, crop residue and age all play a factor in how your crop responds.
By the way, I would not hesitate to resume planting after the cold snap passes and temperatures warm again. Soil temperatures will recover as the forecast is for significant improvement by Sunday & Monday.