As I look out my window on March 7^th to see the snow piles reaching 15 – 20 feet tall, and I look at my thermometer to see it is showing single digits below 0 in central Iowa, I start to ponder “What If” scenarios in my head. “What if this deep freeze doesn’t end and the mountains of snow stick around into April?” “What if WeatherTrends 360® is correct and we won’t see much of an opportunity for field work in April?” Or, “What if Mother Nature turns on a dime and we see major flooding?” Well, those are just thoughts that get in your head after a long, and somewhat snowy, winter.  We better look at the facts rather than some conjured up thoughts in my head.

In general, the optimum planting window for corn in central Iowa falls from April 15 to May 15 with yields declining after that. However, hybrids can respond to delayed planting dates. This is done by the time spent in the vegetative (V) stage and the reproductive (R) stage. Hybrid corn, no matter the maturity, will spend less time in the V stage as the planting day is delayed.  With that said, it does not mean a 105 RM and 115 RM will spend the same amount of time in the VE - VT stage.  It simply means the downward trend in time from planting to silking is consistent in all relative maturities.

Now, we must look at the reproductive (R) stage.  All hybrids increase the time spent in the R1 -R6 stage when a delayed planting scenario is in play.  However, in my experience this time varies from hybrid to hybrid and, in some cases, can have very little effect on the plants reaching R6 (full maturity).

So, the bottom line: “What if we get into a delayed planting situation this spring?” In all cases the time spent in the (V) stage will be reduced and when it comes to the (R) stage, we will have to look at individual hybrids and the time it takes them to reach full maturity. The time spent in the vegetative stage will compensate for the time a hybrid spends in the reproductive stage and it will reach its full potential barring an earlier than normal fall frost.  This means switching hybrids before May 15 is not needed. 

Download a copy of this technical bulletin here: What if...