The first decision of the season may be what day to start planting. That can be a tough call. Right behind it is what happens if you don't get the stand you want. When do you pull the trigger on replanting? That's also a tough decision. In some field somewhere almost every year, you will likely run into that decision.
"Replanting or spot planting can be a tricky issue," says Dave Taylor, agronomist with Harvest Land Co-op in east-central Indiana and an Indiana Certified Crop Adviser. "The first question is often: If final population is low, but fairly even, is it economical to replant?"
Taylor suggests looking to the Purdue University Corn & Soybean Field Guide for help. It contains tables indicating possible impacts of leaving a thin stand or replanting.
Taylor cites this example from the Guide. If corn was planted April 20, and you end up with 18,000 plants per acre, you can still expect to harvest 88% of original yield potential. If that was 180 bushels per acre, you're looking at just under 160 bushels per acre.
Now, suppose you replant the field on May 15th, after deciding the stand is too thin, and also finding a hole in weather patterns allowing you to replant. This time you achieve 30,000 plants per acre. The new yield potential is 95%. If the original potential was 180, the new potential is 171 bushels per acre. It's not 180 because you've sacrificed several days off the beginning of the growing season.
At $3.50 per bushel corn price, you would gross about $560 if you don't replant, and $599 if you do, or nearly $40 per acre more for replanting.
Whether or not that's profitable may depend upon replanting costs. Do you have to pay all or part of the replant seed? Do you have to do tillage before replanting? What does it mean in terms of weed control and herbicide applications?
Depending upon how you answer these questions, replanting, even if you achieve an excellent stand at the later planting date, may or may not be the best economical choice.