Not All Crops Are Small!

Those select fields planted early ahead of the curve.

Published on: Jun 28, 2011

The weather hasn't always been kind to Don Nurrenbern. The Gibson County farmer hopes this year might be different. While it's been a nightmare for some, it's been less of a headache for him.

Just a few days ago, he called to report he had corn tasseling- real corn, not sweet corn. It was planted March 27 on his farm in southwestern Indiana. He was able to sneak in and plant a field during one of the small breaks that farmers got until the end of May or even first of June in some areas.

Knee-high by the Fourth of July may be a real challenge for a few fields this year, but not for this one. Pollinating last week, it should wrap up pollination by July 4. This field may be the exception, and it definitely is, but it highlights the wide disparity in growing conditions and planting windows that have made up this season.

Early-planted corn has done well in test plots and various trials over the past few years. With corn planted late early-late March- it may be possible to get a real comparison this year. We're aware of corn planted as late as June 15.

Let's assume he hadn't been able to plant that field until June 1, like many other people across Indiana. What would that have meant as far as growing degree days that he could expect for his crops? The growing degree day system is used to calculate how fast corn and other crops should mature during the season.. To a point, the higher and faster that these accumulate, the faster the corn should be mature.

According to the Purdue University Corn & Soybean Field Guide, 2012 edition, 67 growing degree days would have already accumulated when the corn was planted on March 17. Those would be of no use to the crop. By June 1,758 typically should have accumulated. That means the corn not planted until June 1 already missed out on nearly 700 growing degree day units. It typically takes 2,400 to 2,600 GDD's to produce a full crop.

The crop planted May 27 would reach 2,700 units in a 'typical' year by Aug 22 in southwest Indiana. However, the corn not planted until June 1 would take until Oct. 10. Note though that Bob Nielsen says that corn planted late tends to speed up and cut maturity GDD units needed by up to 200 per plant. That would still put it reaching physiological maturity around Sept. 20, about a month later than if it was planted at the normal time.