With soybean planting season approaching, K-State Extension agronomist Logan Simon urges farmers to consider row spacing—15 or 30 inches. He says narrower rows often boost yields in low-yield environments by helping the canopy fill in faster. In medium- to high-yield areas with strong plant growth, the yield difference is usually minimal. Still, Simon notes that narrower rows can offer other benefits, like improved weed control and better early-season light interception, even without a significant yield advantage.

“The big thing is weed suppression, especially as we think about herbicide resistant weeds, namely water hemp and palmer amaranth across the state. When we narrow those row spacings up with something like a soybean, we’re able to close that canopy faster, suppress some of those later emerging palmer and water hemp plants as well as all the other weeds that are out there. And really seeing a benefit from that from an integrated weed management perspective,” said Simon.

He explains why soybean growers should consider previous years when picking their row spacing.

“In wetter conditions, this does present some challenges when we have too many plants out there in tuner or row spacing and the problematic in areas where we know we’ve got real hot spots for things like sun death syndrome. So it’s really important to have an idea of what your weather is going to look like and really what your field history is in terms of past experience dealing with soybeans and sun death syndrome as you’re making this decision of 30 versus 15,” said Simon.

He says crop maturity often depends on planting time, but adjusting soybean maturity groups isn’t always necessary. Unlike corn, which responds to heat, soybeans rely on day length. As days shorten and nights lengthen, soybeans naturally shift to reproduction—flowering, setting pods, and building yield, regardless of planting date shifts.