Later Planted Corn Needs Less GDU’s to Mature

The average GDU accumulation at Fargo from May 1-22 is 239 according to NDAWN data. Studies by Purdue University show over three years that early corn hybrids utilized an average of 244 less GDU’s to reach maturity when planted the end of May rather than the end of April or early May. I’m Norwegian – so I’m kind of conservative. Let’s say 150-200 fewer GDU’s are needed to mature. It is about a wash or within 2-3 days of a wash.

So, what does that mean? It means you’ve barely lost any time to mature your corn when planting at the end of May instead of the first of May. That helps answer the question of making maturity when planting in late May rather than early May, doesn’t it?

So why don’t we plant the end of May every year, you ask? Well, if fields are fit and dry enough to plant, the longer season provides an additional 244 heat units to produce a few more bushels and dry-down in the fall. This data provides another reason, and some piece of mind, to stick with your “full” maturity hybrids until “at least” May 20.

What am I talking about with the term ‘full maturity’ for your farm? Example: If you plant the majority of your farm to 90 day corn, some 95 day and some 85 day, your full maturity is 95 day. So my recommendation is this: if you are past the 20th of May, drop off your 95 day from your plan (or some of it), IF you are undersized with your drying setup. If you are set up well with drying capacity, stick to that full maturity corn for a few more days (May 25).

KEEP YOUR RESOLVE or plan to make less money for tax purposes. My sense of humor came out there … sorry. I hope this helps the conundrum rolling around in your mind.