April 2, 2012 | By: | Agronomy

When Should We Start Planting Corn?

Early planting is the buzz topic for this spring. But how early is too early? When should you be planting, or not planting?

Early planting is always the goal for corn production. But we have rarely had a year like this one, where we have the opportunity to wait until we plant.

Research conducted by the University of Minnesota from 1988-2003 shows optimum planting dates of April 21st — May 6th. Yields in years with planting dates earlier than April 18th only averaged 94% of the maximum.

Corn will begin the germination process at 50 degrees F, but planting into cooler soils will still result in good emergence if the weather/soils warm up after planting. Watching the upcoming week’s forecast is essential. If the soil is 50 degrees F and the forecast is for cold/wet weather, leave the planter in the shed.

A couple years back, we had cool rain the first weekend in May, and it hurt germination in most of the heavy ground that was saturated. Imbibitional chilling injury occurs when the seed takes in (imbibes) cool water to start the germination process. The conditions in the first 24-48 hours after planting are the most important.

Corn needs about 125 Growing Degree Days to emerge. This can happen in four days, or it can stretch out over three weeks. Ideally it will occur over 7-10 days, with all plants in the field emerging together. Cool weather will delay emergence, leading to uneven stands and the possibility of reduced yield.

My recommendation is to wait until April 15th to plant, depending on the three day forecast to follow. We all know what a 2″ spring rain can do to our planting window. So if the conditions are fit after that date, it will be beneficial to plant.


Adam Spelhaug, Agronomy Lead CCA

Adam Spelhaug

As the agronomy manager, Adam Spelhaug works diligently to determine the best genetics for our region, bringing growers what they need in their fields. Adam has been making his mark on Peterson Farms Seed since 2005. When he’s not discovering genetic breakthroughs, Adam can be found spending time with his family, golfing or bowhunting. He’s a North Dakota State University alumnus, and he’s proud of it. Don’t take any UND green into his office.

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