The same question comes up every year: Which soybean maturity should I plant?
Ken Ferrie, Farm Journal Field Agronomist, understands growers would like a simple answer. Pick this maturity. Plant that variety. Follow the map.
But to provide the best answer, he usually asks them a question of his own: “What is your system?”
Ferrie’s point to growers is maturity selection is less about choosing a variety and more about building a sound strategy.
What Maturity Actually Means
Angela McClure, University of Tennessee agronomy professor emeritus, says soybean maturity describes the relative time from planting and emergence until the crop reaches about 95% brown pod, just prior to harvest.
“Breeders group varieties with similar maturity length together, and that maturity group becomes one of our best tools for stabilizing yield,” she says in her presentation, Soybean Management by Maturity Group.
Across the U.S., soybeans are sorted not just by maturity group, but into maturity zones — bands of latitude, each with its own daylength pattern. The old advice was simple: plant the recommended group for your zone and you’ll likely harvest before the average frost date.
That guidance still holds, McClure says. But increasing weather swings and warmer, drier harvests mean growers need more than a cookie-cutter approach to variety selection.
“Most farmers already understand they shouldn’t plant just one variety on every acre,” McClure says. “I think about maturity groups the same way.”
One of the biggest shifts in U.S. soybean production? What were once “northern” maturity groups — like 2s and 3s — are marching south, while fuller-season groups are pushing north.
McClure says when you move a maturity group north or south of its traditional zone, it behaves differently. “In our latitude (eastern Tennessee), earlier maturity groups tend to flower and mature earlier, and that can be an advantage,” she says. “You’re accessing different genetics, indeterminate growth and wider flowering windows.”
Early Planting? Protect The Summer Solstice Opportunity
For growers planting early and chasing pre-summer-solstice flowering, the goal is to give soybeans enough time to emerge, capture lengthening daylight and build a longer reproductive window before flowering is triggered.
But planting early doesn’t guarantee an early advantage.
“You might have planted in March, but that doesn’t mean that bean is coming up,” Ferrie says.
Shaun Casteel, Purdue agronomist and Extension soybean specialist, emphasizes that point. Soybeans can branch and compensate for uneven stands, but maturity is still shaped by heat, light and how uniformly the crop gets started.
“We typically need 140 to 160 heat units to get a soybean emerged,” he says.
He adds that cold, wet conditions during the first 12 to 24 hours after planting can injure seed, reduce stands and delay emergence.
That delay can erase much of the advantage growers were trying to gain with early planting.
“It’s essentially like you planted it 10 days later,” Casteel says of seedlings that lose both cotyledons or struggle early.
That’s why for growers chasing early flowering, Ferrie says go with fuller season beans first.
“If I’m wanting pre-solstice, chasing it, pick your fullest-season bean that you were going to plant early and start with it. Then finish with your shorter season bean,” he says.
The strategy gives the highest-yielding, longest-season varieties the best chance to emerge early enough to take advantage of the extended reproductive period.
As planting moves later in the season, however, that advantage fades — and maturity selection changes.
Normal Planting Window? Start With Shorter Season Varieties First
Once planting reaches the “normal” or standard window for your area, Ferrie flips the strategy.
“When you’re planting normal for your zone, our recommendation would be to plant your shorter season beans first and your full-season last,” he says.
Why? Because planting date can become the limiting factor.
If planting stretches across 10 to 14 days, later-planted soybeans can lose some yield potential simply because they have fewer days to develop. Fuller-season varieties planted later can help recover some of that lost opportunity by extending the reproductive period.
“If you’re planting beans over two weeks, you can make up for some of that ‘short bean’ by making sure your last beans planted are your full-season beans,” Ferrie says.
In other words:
- Early planting window: Give fuller-season beans the first opportunity.
- Normal planting window: Start with shorter maturities and finish with fuller-season beans.
That approach spreads risk while protecting yield potential.
Ferrie adds that the same principle applies to double-crop soybeans.
When planting slips into late June or July, extremely short-season varieties can force soybeans into reproduction before they build enough height and nodes.
“If we plant a short-season bean in July, we’re going to have a 6-inch bean we’re trying to cut off the ground,” Ferrie says.
Harvest Capacity Often Sets The Limit
Ferrie believes soybean maturity decisions should include this question: How many acres can you harvest at the right time?
“We can start harvest in the morning and beans will be 13.5%, and before you finish late in the afternoon, they’re down to 9%,” he says. “You’re giving away bushels.”
Many growers focus on avoiding moisture discounts but overlook the loss that comes from harvesting overly dry soybeans.
“A lot of guys compare 14.5% beans with a dock to standard beans they don’t get docked on,” Ferrie says. “They don’t compare it to the 8% beans they’re actually getting.”
Multiple maturities help spread risk, but extreme drought can compress maturity differences. Several varieties can dry down at nearly the same time, creating a narrow harvest window.
Ultimately, the combine helps determine the best maturity plan.
“Some of our guys can knock 80 to 100 acres down a day. Some can knock almost 300 down,” Ferrie says. “It’s about horsepower, platform size, combine size.”
His advice comes back to one point: soybean maturity is not just a seed decision.
It’s a management decision made before the planter rolls.
“You’ve got to look at how many acres you have, how many you can cut a day, and then scale what maturities you want,” Ferrie says. “That’s how you manage risk and still chase your biggest yields.”
