Corn and soybean growers facing slow emergence, shrinking planting windows and cool soils shouldn’t reach for the replant button too quickly, say University of Wisconsin’s Harkirat Kaur and Shawn Conley. They emphasize that field conditions, stand uniformity and return on investment matter more than the date on the calendar.
When damage occurs in corn, the first step is to diagnose what happened to cause the loss, advises Harkirat Kaur, Extension corn specialist at the university.
“Are you seeing stand loss because of seedling issues? Was the hybrid vigor not there? Is there waterlogging? Those things are important to understand, because replanting a field which is damaged is still an extra cost that we incur,” Kaur says.
She believes stand uniformity often matters more than the plant population for corn.
“A uniform stand at a low population is better than having a stand which is at a higher population but has quite a few gaps in it,” she says. “No. 1, it will impact your overall nutrient uptake for the entire field. Secondly, it will also impact your overall operations as you move further into the season.”
Calendar date, surviving stand quality and hybrid maturity all have to be weighed together in the decision.
“If you are looking at a surviving stand which is less than 70% of what your original target was, then you might want to go for a replant,” Kaur says. “But is that replant going to be this soon? It depends if the field is clearly showing no signs of recovery, showing a complete loss of uniformity across the field.”
In many cases, she recommends patience – especially when a frost or hail event enters the picture.
“It is always good to give the crop some time to recover,” she advises, particularly when hail strikes while the growing point is still below ground. “Most of the corn plants in May or early June have their growing point still under the ground (in Wisconsin), and those plants often have the ability to recover from these stresses.”
Running The Corn Replant Math
To frame the replant decision, Kaur walks through a replant return-on-investment scenario for a southern Wisconsin field that was planted May 5 with a full-season 113-day hybrid.
In her example, a stress event drops the stand from a target of 34,000 plants to around 18,000 — roughly 60% to 65% of the original population. That moves expected yield from about 215 bushels per acre to a range of 130 to 160 bushels, or roughly $602 per acre in gross income at current price assumptions.
Replanting later in May means giving up some yield potential to fewer heat units, but it may still pencil out.
“With replanting, the yield potential comes down to about 80% to 85%, which brings the number to approximately around 180 bushels per acre,” she says. “Then we need to account for the replant cost — the cost for new seed, the cost for your fuel, and the time that you’re spending.”
In her example, even after those expenses, the net return on replanting comes out ahead.
“That would bring us to a net of around $675 per acre,” Kaur says. “We are having anywhere around a net advantage of replanting of about $70 to $72 per acre, which could be a bigger number when we are looking at hundreds of acres.”
Still, she frames replant as a decision of last resort.
“Replanting only when the ROI is likely to be positive is critical,” she says. “Keeping ROI over all the operation in mind is the No. 1 thing.”
Nitrogen, Natural Gas And Timing
Kaur also links replant timing to nitrogen management and volatile natural gas markets.
“Natural gas is very critical for agricultural production, because it drives the production of our nitrogen fertilizers,” she says. “When we are looking at overall gas price instability, it reflects in our agricultural cost anywhere between two to eight weeks when it is happening at the global scale.”
Before deciding to replant, she urges farmers to know where they stand on nitrogen availability.
“We need to ensure how much nitrogen is already in the ground and how much nitrogen is still available to be used for the crops,” she says. “Doing another soil analysis might be of use. It might help save the cost of applying more nitrogen, or also putting in hours of applying that fertilizer.”
Kaur says split nitrogen application strategies become more valuable in a tough economic year like this.
“Protecting existing nitrogen investment is critical,” she says. “If you (can), plan for a sidedress. Then replanting before the sidedress is something that can help you save some of your time and also some of your money.”
For Soybeans, ‘Don’t Change Anything’ — Except Row Width
On the soybean side, Shawn Conley, Extension soybean and small grains specialist at the University of Wisconsin, offers his take on next steps at this point in the season.
“In short, basically, don’t change anything except maybe narrow your soybean rows up if you can,” he says. “
Most of his university research plots across Wisconsin are already planted, though some beans are still sitting in dry soil waiting on a rain.
Conley adds that he expects Wisconsin farmers to plant roughly a half-million more soybean acres in 2026 than they did in 2025, based on current projections and spring conditions.
Prioritize Corn Now, Finish Beans After
For growers juggling both crops, Conley says the yield penalty curve has flipped solidly in favor of corn.
“At this time of the growing season, where we are sitting in May, we’re really in this significant decline in yield penalty for delayed planting in corn versus where we are with soybean,” he explains.
“We’re obviously losing yield by delaying soybean planting, too, but not to the extent that we are with corn,” he adds. “It pains me to say, and I tweeted this out last week — it’s time to prioritize corn planting, if possible, if the ground is fit.”
His message to farmers: get corn wrapped up, then come back and finish soybeans.
Seeding Rate And Replant Thresholds
Conley does not see a need to bump soybean seeding rates for now, even with cooler conditions.
His economic analysis shows little payoff to cutting rates aggressively at this point, once seed cost and yield are both considered.
“Optimal seeding rate would be 100,000 seeds per acre, even in this May 13 timeframe,” he notes. “But, that really doesn’t take into effect delayed canopy and management of waterhemp.”
In high weed pressure, Conley says most farmers should stay with about 140,000 seeds per acre unless they have a “very strong weed management plan on the waterhemp.”
On replant decisions, his threshold is clear.
“Generally, what we tell farmers is that unless you have under 60,000 plants per acre and actively growing, don’t do anything,” Conley says. “Don’t even touch that crop.”
If stands fall below that mark, he recommends what he calls a repair plant, not a full reset.
“If it is under 60,000, just do a repair plant, which means you don’t start over from scratch,” he says. “You just go into that field, set the planter at an angle so as not to run over or disturb any of those existing growing plants, and then just plant into your existing stand.”
“The population that’s in the field right now has a higher yield potential than anything you’d be putting in the ground today,” he adds.
Consider Row Spacing
Row spacing is the one area where Conley does advise a change for mid-May and later planting — when farmers have the equipment to do it.
“As our yields have increased due to earlier planting, the yield difference between wide rows and narrow rows shrank,” he says. “However, as we get into lower yield potential — i.e., later planting — then we see those yield differences still remain.”
That shows up particularly in 30-inch rows planted in mid-May and later.
“The longer it takes from planting date to when those soybeans hit R3, the smaller the yield difference between row spacings,” he explains. “Because we’re delayed planting, the number of days between when you plant today and when you get to R3 is going to be in that 50- to 60-day range. You’re going to see a yield penalty if you stick with the 30-inch rows.”
“If you have the capacity — you still have a 15-inch row planter and you maybe haven’t been utilizing that — I think you need to be able to break that out and use that for finishing off your soybean planting,” he says.
