What to expect from corn planted in late-May

Web-based corn growing degree-day tool helps tracks corn progress through the growing season.

Another cool, wet spring in Michigan pushed corn planting in many parts of Michigan to the last two weeks of May. However, patience seems to have paid off, as much of the corn went into the ground under good conditions and the heat and moisture brought the corn up in as little as five days. While planting dates were not what farmers hoped for as they were planning for the 2016 season, the corn looks very good.

Now that corn is coming up, what can producers expect as the corn develops throughout the growing season? A great reference is the U2U Decision Support Tool for Corn Growing Degree Days (GDD), a web-based decision tool developed to allow farmers an easy way to compare current conditions to a 30-year historical perspective. Using historical climatology-based data, the tool offers trend projections through the end of the growing season.

With the U2U Decision Support Tool for Corn GDD, users can select their geographic area; the start date for GDD, this could be the date corn is planted or emerges; the year the grower would like to compare; corn maturity days; and the temperature for killing frost (28 degrees Fahrenheit). In the example in the picture, we used Clinton County with a start date of May 20 and 100-day corn. Thirty years of weather data was used for the comparison and we compared this year’s development to that of 2014 (yellow line).

Even though we are still very early in the season, one of the most striking things the graph shows is that the GDDs for 2016 (green line) are above normal. This is good news for corn development and if this trend continues and we get timely rains, there is potential for corn to overcome the later plant date. However, a common concern with later planted corn is whether or not it will reach maturity before the first frost. On average, the first killing frost in the fall for this area is Oct. 26. In this example, corn will reach black layer prior to that. However, there have been years where the frost comes earlier in the season, so there is still risk.

Using the U2U Corn GDD tool, growers can run any number of scenarios to answer questions unique to their situation. Changing the inputs of planting date and corn maturity days are easy with this tool. Using current projects of weather, knowledge of the growers system and 30-years of historic data, growers can make informed decisions in a cool, wet spring.

The U2U Corn GDD tool was developed by Useful to Useable (U2U), a team made up of faculty, staff and students from nine Midwestern universities working to develop decision-support tools and resources to support resilient and profitable crop production. U2U is funded by a grant from USDA.

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