Corn School: When to switch to shorter-season hybrids


When should you consider switching corn and plant a shorter-season hybrid?

That’s a question many growers in some southwestern regions of Ontario are wrestling with as the calendar pushes ever closer to June. Spring weather conditions in many areas of the province have been good and planting is proceeding at a strong pace. However, heavy clay soils in Essex, Chatham-Kent, Lambton, Elgin, Haldimand, and Niagara counties have been deluged by rain. In some areas, planting has barely begun.

Should farmers in these areas be contemplating shorter-season hybrids? In this episode of RealAgriculture’s Corn School, AGRIS Co-operative agronomist Dale Cowan says it’s time for farmers in these areas to start thinking about making a switch.

If the weather co-operates, Cowan believes that growers in Essex, for example, should be able to get going in the next few days and get corn in the ground. “Growers are probably okay until the end of the month. After that, farmers have to start asking should I be changing my heat unit maturities on my corn.”

Cowan says the rule of thumb is to drop 100 heat units per week for delayed planting, but he’s not liking the long-range forecast, which calls for a cooler summer, and it’s difficult to expect the ideal fall growing conditions that helped the Ontario corn crop mature in 2017.

“I’m recommending our farmers drop 200 heat units right off the bat and give ourselves a chance at dry-down and black layer in the fall,” says Cowan.

As planting stretches on, Cowan believes farmers may not have an appetite for June-planted corn and many acres will switch to soybeans. He notes, however, that moving to corn hybrids that mature with 200 fewer heat units doesn’t always mean a yield penalty. Shorter-season hybrids can perform just as well in the right growing conditions.

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