Don’t give up too soon…


Blog_QuoteWe’ve all heard the saying, “Anything worth having is worth waiting for.” But did you ever think about how this familiar quote applies to farming? We must remember that planting season is more like running a marathon than a sprint.

Highly competitive runners have to deliberately pace themselves. They also have to avoid jumping the gun. This, too, applies to farming. You see, many farmers jump the gun and switching corn hybrid maturities too soon. Corn planted in early June can make decent yields, and there’s no need to switch from corn to soybeans until after that.

When you switch maturities, you forfeit maximum potential and have essentially decided to lower your yield expectations! Based on my experiences over the past 35 years – as well as research findings from many Midwest land grant institutions – I can tell you with confidence that full-season hybrids and varieties outperform early maturing hybrids and varieties.

There becomes a point in time where the advantages of planting a full-season hybrid diminishes to the point where shifting to a shorter-season hybrid or variety will generally result in drier corn and higher yields come fall. Following is a summary of factors to consider when deciding whether to switch corn or soybean maturities.


I’ll use northern Iowa and southern Minnesota as an example. If your maturity range is 98- to 109-days (which is what I use for the Latham Research Farm), then you should generally not deviate from those maturities until at least May 25. If all you have left to plant is your 98-day hybrids, then you can safely extend your planting window to about June 7-10. On the other hand, if you only have your 109-day hybrids left to plant, you’ll probably be better off switching to 95- or 99-day products.

That brings us to the next subject… if you must switch, how early of a hybrid is needed? You don’t need to take it to extreme and switch from 109 RM to an 85-day hybrid. Research has proven that it pays to stay closer to your “normal” maturity. Switch to hybrids that are about 5 to 7 relative maturity units earlier than full season for the region. Yields in this scenario will be greatly improved if northern Iowa and southern Minnesota farmers (from the example above) move toward a 92- to 95-day hybrid that is more closely adapted to the area.

The decision to switch maturity with delayed corn planting is difficult because of so many variables including: available GDUs, first frost date and fall drying conditions. With this in mind, here are some general guidelines:

within Iowa
Full Season RMSwitch to
on May 20
Switch to
on May 30
South of I-80114-117108-111108-111
North of I-80109-113105-108105-108