Adjust planter for different sizes, grades

Indiana seed corn producers harvested about 60% to 70% of a normal crop last season. For a variety of reasons, there should be plenty of corn to plant. A scramble may be on to get as many units of top sellers as you like. And you may not be able to be choosy about the seed grade and size.

“Every farmer has a preference on size and grade they like to plant,” says Justin Welch, an Indiana-based Pioneer agronomist. “This year they may have to be more flexible to get the genetics they want.

Key Points

You may have to be flexible on size and grade this year to get genetics you want.

To plant large rounds in a vacuum planter, you may need to up the pressure.

Metering stands coupled with your own seed lot by lot can zero in on accuracy.

“If you’re planting a different size or grade than normal, pay attention to each lot of seed and calibrate your planter carefully,” Welch advises.

There could be more large rounds in areas where seed producers were hit by hot, dry weather. Large rounds are produced at the butt of the ear. In some fields there was better fill at the butt than toward the tip.

Check settings

If you’ve got a vacuum planter and you’ve been using 17 or 18 pounds per square inch of pressure, you may need to use 22 with large rounds, Welch says. If you don’t make changes, singulation of kernels can drop off dramatically.

Welch assisted with a plot where the planter was equipped with a Precision Planting 20/20 Seed Sense monitor that digitally reports singulation. As they changed sizes and grades across the plot, the monitor showed dramatic differences.

“When the operator adjusted the vacuum pressure, large rounds planted as well as anything else,” Welch observes. An advanced monitor allows you to see immediately if size, grade or some other factor is causing inaccurate singulation, he notes. Past studies indicate that precise stands can yield 2% to 5% more.

Tips for better stands

Welch offers two tips that could help if you’re planting different sizes and grades. First, if you have a planter with finger-pickup mechanism, this would be an ideal year to have each unit tested on a test stand. Many seed and implement dealers have MeterMax stands and offer this service at a reasonable cost. Most can also test vacuum planter unit accuracy.

Take a sample of seed you’re going to plant to the testing location and have them calibrate using your own seed. Some farmers test each lot of seed in the toolshed so they will know the vacuum adjustments to make.

For those planting Pioneer seed, there is a tool available on the Pioneer website to help you do the same thing, Welch says. Enter your lot number and the software will tell you the exact settings on your brand of planter for best performance.

From the Pioneer website, find “Plantability tools.” And follow directions. Or ask a seed rep for help.


Size matters: If you usually plant small rounds but can only get large rounds, adjust your planter accordingly this spring.

This article published in the February, 2012 edition of INDIANA PRAIRIE FARMER.

All rights reserved. Copyright Farm Progress Cos. 2012.