Corn is knee high by Fourth of July

Ralph Boehlen of Hustisford walks through a patch of his 100 acres of corn off of Sawmill Road to check its height and health. The cornfield was planted on May 10, but Boehlen said it is growing behind average. This time last year the corn was chest-high, whereas the stalks are currently just over knee-high.

Although many farmers got off to a slow start this year, their corn is well on track with most fields staying true to the old adage that the green stalks of corn should be “knee high by the Fourth of July.”

“You can go out into some of those fields today when its 95 degrees out and you’ll find it’s growing fast,” David Laatsch, interim crops and soils agent for the Dodge County UW-Extension, said. “We’ve had some very adequate and timely rains and sunshine to bring the corn up to speed. It is quite recovered from the late start.”

Laatsch, said the traditional saying has its roots in the northern Corn Belt region of the country. It is a method sometimes used to determine if the corn plants are mature enough to develop a satisfactory crop by the fall.

“The ‘knee high’ stage of growth is actually a stage of maturity rather than a precise measurement of the height of the corn,” Laatsch said. “When the sixth leaf of the corn plant has emerged from the stalk and the uppermost growth point has emerged above the soil surface it is commonly called knee high.”

Laatsch explained that at this point of maturity, the leaves form a canopy over the rows, gathering the maximum amount of sunlight during the remaining part of the growing season. He said the heat and sunlight of July and August will allow the plant to produce enough sugar and starch to become mature before the first frost of fall stops the plant’s growth.

Although the corn is knee high in most fields around the county, many farmers are comparing their crop to what it was last year.

“We’re not quite as far along as we were last year,” Laatsch said. “Corn that is knee high today was hip high at this time last year.”

Laatsch said the corn growth also varies depending upon the location of the field in the county. Many fields on the west side of the county were planted before those on the east side of the county.

“Soils on the west tend to be darker and that results in the warming in the spring a little quicker which makes it dry out a little quicker,” he said. “Then you get into the rolling hillsides. Those fields dry out nicely on the top but the side hills don’t dry out as quickly.”

Even though the crop isn’t quite as far along as last year, Laatsch said he’s hearing from many farmers who say they are just thankful they aren’t in areas of the country that are seeing historical flooding.

“The thing that I have been saying and a lot of farmers are saying is to consider those in the flooded areas along the rivers in Iowa and North Dakota where they’ve lost their entire crops for the season,” he said. “That makes us very grateful for our conditions.”

Laatsch said because the length of the growing season is a limiting factor in Wisconsin and other northern states, the “knee high” stage is very important. In the southern portion of the country many farmers will plant their crop a month or two earlier and their corn is often tasseled and beyond by the Fourth of July.

“If the corn is not ‘knee high’ stage by this date, the plants will be unable to gather as much sunlight as the days begin to shorten and the angle of the sun’s rays become more indirect,” he said.

The roller coaster of demand and supply has put pressure on the corn market. With over 40 percent of the world’s corn grown in the United States many countries are taking a close look at this year’s growing season. The size of the crop has a major impact on the world economy.

“At the G20 world conference last week the only topic that was discussed was food and agriculture,” Laatsch said. “That tells you how significant this year’s crop is.”

Laatsch said although that conference likely revolved around rice and wheat rather than corn, there is always a substitution such as corn that is used in various products. As a result all of the grain commodities are considered together.

Other crops for the growing season typically follow the rate of growth of the corn. Many area farmers got their first crop of hay done right around Memorial Day and some are finishing up on their second crop, which is also about a week behind last year’s season.

Soybeans are following the same rate of growth as the corn and wheat is maturing very rapidly, according to Laatsch.

“We’ve seen the wheat color change in the last week. I’m guessing that harvest will be right about normal,” he said. “We’ll likely start to see combines roll out by the end of the second week in July.”

For more information about corn and the economic impact of agriculture in the county, visit

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