Corn planting season is almost upon. Okay, for some there is already corn in the ground. Planting is one of the most important, if not the most important, field operation of the year. Now is a good time to think about planting considerations. Often I get asked what planting date is the best. In order for me to answer this, I first need to know what the growing season conditions will be. That is probably not going to be very accurate, so, that means we have to rely on the past to give us the best indications of when planting should occur.
Generally, the corn planting window in Iowa that results in 95% yield potential is April 15 to May 5. For soybean the optimum planting window shifts to April 25 to May 15. Picking a specific planting date pretty risky. Planting should not be determined by date alone but rather by a combination of date and local field conditions. Wait to plant until soil temperature is 50oF and rising. Wait until soil moisture is adequately dry to minimize the risk of sidewall compaction. Soybean like slightly warmer soil conditions than corn for germination and emergence. The importance of the 5 to 10 day weather forecast is to ensure that germination and emergence occurs in a timely manner. When it comes down to it, cold injury (imbibitional chilling) occurs when cold, wet conditions occur within 24 to 48 hours of planting. Don’t push planting the last 40 acres just to get them in before a cold rain, this will hurt stand establishment and diminish seedling vigor.
Good luck and safe planting!