The calendar is slipping by. Maybe you've had good soil conditions and made the decision to plant whether it was as warm as you like or not. It's tough to knock that decision because there have been years when you would wait and then it rains for three weeks. All of a sudden it's late May or early June and you're battling the calendar that will catch up with you on the back end of the season.
Dave Nanda, Director of Genetics and Technology for Seed Consultants, Inc., is a believer in early planting. He says over time earlier-planted crops, particularly corn in his case, tend to yield more. However, he's also a realist. He knows it takes a certain amount of heat to get corn up and growing.
Heat is measured in Growing Degree Days. The base unit for air temperature to begin calculating growing degree days is usually 50 degrees. If it barely passes 50 degrees at night and slips below it overnight, GDDs don't accumulate very quickly.
Bob Nielsen, Purdue University Extension corn specialist, says it takes about 120 GDDs to get corn form planting to emergence. If you're accumulating 15 to 20 a day, fairly normal in some parts of the country for this time of year, you can get a crop up in seven to 10 days. But if you're only getting from none to five per day, as was happening earlier in parts of the Corn Belt, it will take plants longer to emerge. It's simply a matter of plant dynamics.
Bad things can happen when plants sit too long in the ground in cool, wet soils. They become sitting insects for pests, like grubs and wireworms if they are present, and seed treatment insecticides only last so long.
So do you wait if you haven't planted yet, hoping next week will be warmer? What if next week is warmer but wetter? What if you don't get back into the field for two or three weeks?
That's why one farmer in the southern part of the Corn Belt planting in mid-April said, "I would rather store it in the soil than in the sack. When it's ready it will come up. Today's genetics are tough."