JUDSON — How about Sky High by the Fourth of July?

When Vern Koehler went to a field tucked in the woods between Nicollet and Judson on July 3 to measure the height of field corn, he needed a step ladder.

“I measured it on the third and when I came back on the fourth it’d grown 6 inches,” said Koehler, who is retired and rents the field to farmer Stuart Bruns.

The measurement to the tip of the top leaf: 10 feet, 1 inch.

While the old adage of hoping corn is “Knee High by the Fourth of July” has been out of date for a long time, having 10-foot corn on the Fourth is extraordinary.

“I’ve been farming 60 years and I never saw anything like this,” said Koehler, who decided to measure the corn for a “tallest corn contest” run by the Nicollet Lafayette Ledger.

Up until perhaps the 1950s, corn often was no higher than the knees by this time of year. But thanks to hybrid seed and better fertilizer, the old saying is dated.

Still, the corn fields of southern Minnesota this year are towering.

“We started so good,” said Kent Thiesse, a former extension service agent and now ag banker at MinnStar Bank in Lake Crystal.

“We had perfect conditions from planting to the end of June, except for some spots of a little hail and some heavy rains.”

But the fields are in dire need of measurable rain in the next week or so, as the corn is tasseling and silking — the time when the cob and kernels of corn are set.

“It’s vital to get rain at this stage,” Koehler said.

Rain soon means the big stalks of healthy corn will set large ears with a lot of kernels. But continued dry conditions mean the towering stalks will divert any moisture and energy away form ear development and into keeping the plant alive.

“The yields are going to start getting affected,” Thiesse said. “We’re getting right on that borderline, the next week or so. The stress factor is going to take a chunk off the yield if we don’t get rain soon.”

The good news, he said, is that the heavier black and clay soils still have good subsoil moisture.

“We’re certainly not facing that disaster stage. There’s subsoil moisture there unless you are in the lighter (sandier) soil. Some of those nice looking crops on light soil are starting to reverse,” he said.

“Overall, our crops are good to excellent.”

He said soil moisture is shortest south and west of Mankato, which missed out on rains in June. “They were only getting 50 to 75 percent of the normal rain in June, so it’s a little tougher there.”

While temperatures continue to soar, Thiesse said corn benefits from what humans hate — high humidity.

“People don’t like it, but high humidity is better for corn. It gives the corn some moisture and reduces the stress when it’s hot.”

Soybean crops, which are also strong, are in a better position to withstand a little more dry weather.

“The difference with soybeans is you have a wider window. If they have decent subsoil moisture, they just glide along and almost go dormant,” Thiesse said. “Then when you do get some rain they bloom and produce pods.”