ISU Extension Agronomist Offers Insight On When To Plant

Although Iowa has enjoyed some good drying conditions the last few days, it's not going to last, ISU Extension agronomist says.

Published on: Apr 30, 2013

"Although we've experienced some good drying conditions in Iowa the last few days, it's not going to last." With an eye on the latest weather forecast, that's what Iowa State University Extension corn agronomist Roger Elmore told Wallaces Farmer on April 29.

"Rain is forecast for most of the rest of this week in Iowa. And it is not going to stay warm either. Temperatures, after teasing us for a few days, will plummet by midweek. Central Iowa's forecast for temperatures for the week show that they will drop into the mid-30's Wednesday through at least Saturday. If that happens, the forecast for growing degree day or GDD accumulations will barely reach half the normal 60 GDD for the next 7 days in central Iowa. Soil temperatures will nosedive."

KEEP CORN SEED IN BAG: This weeks weather forecast is for 5 to 7 days of cold, wet conditions. Thats a good reason to keep your precious corn seed in the bag. Central Iowa temperatures are expected to drop into the mid-30s on Wednesday May 1. Although corn kernels will absorb soil moisture when soil temperatures are less than 50-degrees F, the kernels wont begin germinating until soil temperatures reach 50 degrees F or higher.
KEEP CORN SEED IN BAG: This week's weather forecast is for 5 to 7 days of cold, wet conditions. That's a good reason to keep your precious corn seed in the bag. Central Iowa temperatures are expected to drop into the mid-30s on Wednesday May 1. Although corn kernels will absorb soil moisture when soil temperatures are less than 50-degrees F, the kernels won't begin germinating until soil temperatures reach 50 degrees F or higher.

Iowa is about to fall behind on the "optimum corn planting date"

"Obviously, we are pushing the 'optimum corn planting date' now, and with another week delay we will be even further behind," notes Elmore. In an ISU Extension Integrated Crop Management News article earlier this spring, titled "Corn planting FAQ's, he discussed several items including corn planting dates. Here's a summary of what he had to say:

"Optimum corn planting dates vary across Iowa, depending on soil moisture and temperature, from April 11 to May 13 in southern Iowa; April 15 to May 2 in central and northwest Iowa; and April 12 to May 2 in northeast Iowa. Although corn kernels absorb soil moisture when soil temperatures are less than 50°F, they will not begin germination until soil temperatures reach almost 50°F or higher.

If the 5 to 7 day forecast calls for cold soil temperatures and wet weather, keep your seed in the bag

"If the sun is shining and the calendar date for your part of Iowa lies on the early side of the range listed above, and if soil temperatures are in the high forties or higher and climbing, checkout the 5 to 7 day forecast. Plant corn if the forecast calls for more of the same. If, on the other hand, the 5 to 7 day forecast calls for a good chance of cold wet weather settling back in for a while, keep the seed in the bag."

Elmore concludes: "This week--the week beginning Monday, April 29--the bleak 5 to 7 day forecast encourages us to keep the seed in the bag. We faced a similar circumstance in 2011." These ICM articles provide more information on situations like we are facing now:

Wait to Plant Corn with Forecast of Impending Cold Spell

Early-season cold stress

To answer the question his friend asked him on April 28 "Should I plant?" Elmore says, "No. Keep that precious seed in the bag this week. We've not yet experienced the best planting date for 2013….and it won't likely be this week!"