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College of Food, Agricultural, and Environmental Sciences


Stick to Recommended Practices When Planting Corn

April 4, 2006

COLUMBUS, Ohio -- With corn planting fast approaching, Ohio State University Extension agronomists hope Ohio growers keep in mind the trials and tribulations experienced last season when establishing their crop.


Peter Thomison, associate professor with the Department of Horticulture and Crop Science, said growers could reduce production risks if they remember the successes and adhere to the lessons learned from last season.

"Growers need to be cautious of some of their production practices when planting corn, especially when dealing with uncontrollable events like the weather," said Thomison, who also holds a partial research appointment with the Ohio Agricultural Research and Development Center.

Thomison hailed growers for early and prompt planting last season, one of the few bright spots in an otherwise lackluster crop year. Warm, dry conditions allowed growers to plant earlier than anticipated.

"About 70 percent of the corn was planted by May 9, which was ahead of schedule," said Thomison.

Given the unpredictability of weather, however, Thomison encourages growers to stick to recommended planting practices.

"We ran into several issues last year," he said. "The main thing we saw was that as the ground turned dry, some growers were planting deeper than normal because they wanted to take advantage of any moisture. But that backfired on us when we ran into that cold, freezing rain and snow for a seven- to 10-day period after April 21."

The rule of thumb when planting seed in mid-April is to plant between 1.5 to 2 inches deep. Any deeper and growers are setting themselves up for emergence problems. Planting any shallower could result in poor nodal root establishment that could spell trouble for the crop later in the growing season, especially under drought conditions.

Another problem experienced last year was surface crusting of soil, created when heavy rains come into contact with excessively tilled soil. The result is a seed growth barrier and the consequent corkscrew phenomenon characteristic of a plant struggling to emerge from the ground.

"Growers should try to avoid overworking fields, because it just predisposes soils to crusting if heavy rains occur," said Thomison. "Last year we found that fields that weren't tilled as extensively had a better chance of recovery than those fields that were tilled too much, especially in fields where soils were overworked to a powdery consistency. No-till fields also tend to perform better than conventional fields regarding this matter."

Juggling replanting with potentially late-emerging corn plants can be a challenge for growers, as the outcome of both is not so black and white. Last year, more than 30 percent of the corn crop was replanted in many counties because of assumptions of damaged corn seed. However, some growers experienced late-emerging corn in their replanted fields.

"What we learned from this is that corn can emerge from the ground 40 days or even longer after it's planted," said Thomison. "Many growers tend to question the viability of a crop from the standpoint of emergence -- basically how long will it take for the crop to emerge and will late-emerging plants produce a normal ear. We found that in some cases late emerging plants performed better than replanted corn, and vice versa."

To avoid early season planting problems, Thomison stresses that growers plant well-drained fields first and plant in fields that are prone to drainage or flooding problems last.

"Because those fields would probably flood in late April or early May, they are more likely to require replanting," said Thomison.


Candace Pollock
Peter Thomison