Optimum corn planting date for Michigan: Wait for warm soil

The beginning to middle of May is the optimum corn planting period in Michigan. Research has shown that there are no agronomic or economic advantages to planting corn before April 20.

One of the many lessons learned from the 2012 season was the need to wait until the soil has warmed up to the right temperature before planting corn. The abnormal, early warm weather in March and higher than normal growing degree accumulations enticed some farmers to plant corn in early April, disregarding the soil temperature. Most corn hybrids will not germinate if the soil temperature is below 50 degrees Fahrenheit. For much of April, the soil temperature conditions remained too low for uniform germination and emergence.

The longer the seed lies below ground without emergence predisposes the seed to potential chilling injury, disease and insect damage. The resulting unevenness in plant stands was evident on many of the early planted corn fields.

Previous planting date research by Michigan State University Extension specialists has consistently shown that there would be no agronomic or economic advantages for planting corn before April 20 in Michigan. For much of Michigan, the optimum corn planting period usually is from the beginning to middle of May. Because of the shortness of this optimum planting period, most growers plant some corn before and after the optimum dates. It is usually an advantage to error on the early side compared to the late side of the optimum period.

If the field conditions are right, the soil temperature is staying above 50 F and the calendar says late April, then plant corn. You should also make sure that the projected planting date is within the period specified in the crop insurance policy. If, however, the soil conditions are not right, then delay planting until early May without a yield penalty.

An inexpensive soil thermometer gauge is all you need to keep tabs on soil temperature 2 inches below the soil surface. You can also visit MSU’s Enviro-weather to check the soil temperature and several other important weather features from a station closest to you.

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