Don't jump the gun on corn planting. The weather has warmed up early this spring, but it's still March. It's far too early to plant corn in Iowa. That's the word from Roger Elmore, Iowa State University Extension corn agronomist.

"We've got a month or so yet before we should start getting serious about planting corn in Iowa," he said on March 19. "A lot can happen with the weather during the next 30 days that could have a negative impact on seed germination and the growth and development of corn seedlings. We almost always have some cold weather between now and the middle of April in Iowa. We could have snow and cold rains. You don't want to put corn through that kind of an environment."

Does It Make Sense To Plant Corn So Early?

Some farmers learned that lesson the hard way in the spring 2011 planting season, he recalls. Last year around April 12 weather conditions were great and the soil was warming up and working well. But there was a forecast for cold, wet conditions including snow in the next five to seven days, and that is what indeed happened.

Remember, the early plant date for crop insurance purposes is April 11 in Iowa

Planting corn and soybeans too early can result in very uneven or ragged stands if the plants do happen to emerge. "If you are trying to maximize yield, that is not the kind of stand you want," says Elmore.

Crop insurance coverage also is a consideration in determining when to start planting, points out Kurt Koester of AgriSource Inc., in Des Moines. That is a grain marketing consulting company that also sells crop insurance. The early planting date in Iowa for crop insurance purposes is April 11 for corn. For soybeans it's April 21. You can start planting on those dates and still qualify for replant coverage. However, farmers who decide to go ahead and plant corn before that crop insurance "early plant" date will give up their replant coverage, which amounts to $45.44 per acre this year.

The crop insurance date for early planting in Iowa, Minnesota and Wisconsin is April 11. For Nebraska it's April 10 and for Illinois and Indiana it's April 6. For northern Missouri it's April 5. On March 19 Koester said he'd already heard of quite a bit of corn being planted as far north as southern Illinois and Indiana during the week of March 12 to 19. He'd also heard a rumor that someone had planted a small field of corn in southern Iowa on St. Patrick's Day, March 17.

Generally, for Iowa what would be the ideal planting date for corn?

"The crop insurance date is April 11," says ISU's Elmore. "Our ideal planting date really starts just a few days after that around the state." The best time is from about April 15 to the end of April in the northeast and north central parts of the state, according to Iowa State University's latest date of planting studies for corn. That "best period" runs through the first or second week of May for the rest of the state.

"If you plant too early, you do lose some yield potential," says Elmore. "But if you plant too late you lose yield potential too. So there is an optimum period we are shooting for and usually it's the last week or so of April in Iowa."

If farmers could get into the field during the last week of March, and if they didn't have a freeze through the rest of the spring, would there be any yield advantage for planting corn in March—if there is no freeze? "Probably not," says Elmore. "The optimum over a period of time is to start planting April 15 to 20 if the weather and soil conditions are favorable. We've planted corn in some of our date of planting studies during the first part of April but we've never planted corn as early as March."

Now is time to get everything ready, so you're prepared to go in mid-April

Elmore says he'd go ahead and get things done now that can be done, to get ready to plant in the last half of April, when the timing is more favorable. "Do everything now except put the seed in the ground," he advises. "Get your planter ready and adjusted so you are completely ready when the weather breaks in the middle of April so then you can get started planting corn."

With the weather so warm so early in Iowa this March, "this would be a good year to do your own date of planting study for corn," notes Elmore. "That is, if you wanted to put in a few rows here and there, just to see what happens. But I think you will be disappointed if you go in and plant corn this early—while the calendar is still in March."

Another thing to keep in mind is cost of replanting, and availability of seed

Another thing to keep in mind this year is we are working with a relatively short seed supply due to low seed yields this past year, and an increase in the amount of acres to be planted to corn this year, says Koester. Should you need to replant, you're probably not going to get your first choice in hybrids. That could mean taking an inferior corn hybrid. Also, replanting can be costly. Some seed companies charge less than full retail price for replant seed, but they might require planting corn on or after a certain date--such as the crop insurance date.

Unless temperatures remain far above normal over the next month or more, the risk of planting in March or early April may well outweigh the likely return. But for farmers who want to be able to say that they planted corn earlier than ever before—and before their neighbors—2012 is providing the chance.