Knee high by the Fourth of July?

Sweet corn, one of summer’s finest treats. — Rosana Prada/Flickr

What does our nation’s birthday have to do with what’s going on out in the fields where that favorite summer treat, corn on the cob, is ripening under the blazing sun?

If “Knee-high by the Fourth of July” rings a bell, you’re familiar with the traditional rule of thumb for gauging whether corn is on track for a good harvest. But wait – that standard originated generations ago in the Corn Belt and applied mainly to field corn raised for livestock feed, corn that still had a lot of growing to do before harvest in the fall.

Sweet corn, the tender kind that humans favor, matures much earlier. We hope to be eating it by July 4th, not dampening our knees with its dewy stalks. So, maybe we should default to that other widely known corn benchmark from Rogers and Hammerstein’s beloved musical “Oklahoma!” In the lyrics of “Oh, What a Beautiful Morning” we have this (possibly fanciful) measurement: “The corn is as high as an elephant’s eye.”

Well. Inquiring minds want to know. Knee high? Elephant’s eye? And how high, actually, are those targets on average, vis a vis the anticipated height of corn as we know it in the age of modern agriculture? A few years ago, I investigated.

Ray Samulis, agent at the Rutgers Cooperative Extension Service in Burlington County, is widely acknowledged as “Mr. Sweet Corn,” having studied it and test-grown umpty-ump varieties for the past 30 years, both locally and at the Snyder Research and Extension Farm in Pittstown. According to him, modern seed genetics and newer growing methods have changed things considerably.

“At up to 4 feet, the earliest types ready in 65 to 70 days from sowing look almost mismatched in the ratio of ears to stalk, but breeders have been working toward a plant that has more yield and less foliage,” Samulis says. “The mid and later season types harvested in 72, 78 or 82 days are taller, maybe 6 to 6 ½ feet. These generally have bigger ears and are sown at intervals through spring to provide a long harvest.”

“Early” is a relative term, with farmers reaping a premium for being among the first to bring corn to market. About 20 years ago, a planting innovation canted the odds in their favor. Corn farmers now commonly sow seeds in trenches covered by vented clear plastic that forms a mini-greenhouse, warming the soil and spurring earlier germination.

“A famous Rutgers agent named Norm Smith was among the first to get farmers to use plastic,” says John Grande, former director of the Snyder farm. “Everybody cheered to get really high quality sweet corn ready for the Fourth.”

Out in the field, no one is arguing.

Corn in the field, a beautiful sight. - agrilifetoday/Creative Commons

“Years ago, you really had to be blessed by the good Lord to get corn by the Fourth of July,” says Jim Giamarese, who farms in East Brunswick. “This year with the warm spring weather, we planted super early. The 72-day corn was knee-high by April 28 – that’s about 21, 22 inches -- and we picked our first ears on June 13. I don’t believe we’ll break that record again.”

Reportedly, some South Jersey farmers have harvested corn on June 3, but the very earliest corn (ready in 65 days) isn’t that tasty and Giamarese doesn’t plant it. Samulis can snow you under with a blizzard of facts about the genetics of modern “super sweet” corn. The take-away is that varieties maturing a little later, at 72 to 82 days, are programmed to have an enhanced sugar content and to delay the conversion of those sugars to starch.

(Word to the wise: the changeover from sugar to starch takes place quickly and is speeded up if harvested corn doesn’t stay cold. Go for corn picked first thing in the morning and kept chilled, bring your cooler along for transport and refrigerate corn the moment you get home. Pass up any farm stand that has its corn sitting in a bin out in the sun – it’s already shot.)

Sweet corn grown in New Jersey is almost exclusively white or bi-color (yellow and white) since in one of those regional quirks, consumers here don’t prefer all-yellow corn. It may be a hangover from devotion to the old-time favorite ‘Silver Queen,’ which associated “white” with “sweet and tender.” If you wonder why you never see ‘Silver Queen’ anymore, it’s because while consumers loved it, farmers hated the way its weak stalks would often topple in big winds, leaving whole fields lying in the mud.

The reputation of our sweet corn is right up there with the renown of our tomatoes, by the way. Back in the ‘90s, Samulis hosted a luncheon for ag agents from around the country, including those from the Corn Belt.

“They were wrapping corn in napkins to take it away, and asking more than once ‘What kind of sweet corn is this?’” he says. “We opened their eyes.”

Kurt Alstede, a prominent farmer in Chester, says we should be proud of our corn, which he ships not only to New York and Philly markets, but to customers in Florida, Colorado, Arizona, Bermuda and St. Croix. These buyers are mainly former New Jersey residents pining for the sweet corn they knew and loved, unavailable elsewhere, he says.

If you think we’ll never get as far as the elephant’s eye – 8 feet, 2 inches on average -- you would be wrong. While sweet corn lingers at thigh to chin level, field corn grown for those spooky Halloween corn mazes winds up as high 12 feet, well above a pachyderm’s long-lashed eyeball, providing he’s got four feet on the ground.

“It’s a completely different kind of corn,” Alstede says. “It gets big, really big, by September -- but you wouldn’t want to eat it.”

There you have it, knees, eyes, ears and all. I’ve done my part. Now I’m looking forward to the steamy, buttery, sweet and tender taste test.