Late last June, Eric Manson stood at the edge of his corn field just south of the Clinton/Jackson county line, his corn towering above his 6-foot-1-inch frame. 

Last week, the plants reached just above his knees. 

What a difference a year makes. 

Manson’s corn looks as good or better than that in many Eastern Iowa fields as an unusually cool spring and early summer have stymied growth. Rainy weather limited the number of suitable planting days, forcing many farmers to get their corn and soybeans in later than usual. 

And while the old Midwestern adage about corn being “knee high by the Fourth of July” was a good rule of thumb a couple of decades ago, it’s an outdated benchmark, said Mark Licht, an assistant professor of agronomy at Iowa State University.

“Knee-high is not necessarily a great indicator. It’s a sign that we’ve had a rough spring. Anymore we talk about shoulder high by Fourth of July,” he said.

Because March and April were cool, it took the soil longer to warm up, Licht said. That impacts plant growth.

“Then we got into May, and we’re not only cool, but we had a lot of rain. Getting planting done on time was a challenge,” Licht said. “The timing of the rainfall was a challenge. We’d just get dried out and it would rain again.”

Many farmers planted weeks later than they usually do. Manson planted his corn on May 16, squeezing the work in just before a bout of rainy weather shut many others down for days.

 “The yields won’t be the same, but it is what it is,” Manson said, although he considers himself lucky to have planted when he did.

“I’ve heard horror stories” Manson said.  “The cold weather, the lack of sun, the rain. So many things go into it.” 

He and Licht both noted the hot weather last week was welcome. 

“If this keeps up, you’ll see a lot of growth,” Manson said. 

Licht agreed. 

 “The good news is that we should have a week of warm weather. The cool weather and late planting before now has kept corn from putting on height and growth. You’ll be able to see changes in corn daily. It’s going to put up new leaves and height and hopefully get back to normal growth. 

“This week is going to hopefully turn things around for us,” Licht said.