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Plan Now for Summer Sweet Corn Success
Plan Now for Summer Sweet Corn Success

Q. I want to grow ornamental and sweet corn this summer and know they are heavy feeders. Can I grow them without adding chemical fertilizer to the soil? Is extra compost enough? Thank you,
    ---Greg in Leelanau County, Michigan
A. Good thing you emailed before you planted, Greg; because "ornamental corn" is just a way to describe a field (or 'drying') corn that happens to have amazingly colored kernels. (Bright red, metallic green; every color of the rainbow and then some….) And you CAN'T grow a field corn and a sweet corn at the same time and get sweet corn.

The grains in the pollen stalks that appear as the 'tassels' atop the plants in summer are spread by the wind, with every grain that falls into a tangle of corn silk becoming a kernel of corn inside the cob that will develop there. These wind-blown grains can cover quite a distance, and that can create serious problems, because field corn pollen makes sweet corn taste starchy. So you should first choose which kind of corn you want to grow….

Or seek out one of the old heirloom field corns with what's called a 'milk stage'. Varieties like Bloody Butcher, Mandan red, Aztec Black and Rainbow Inca can be very sweet if picked during the perfect window, which is the same as for regular sweet corn. How to find that window? Mark the date when half the plants have visible silks; the ears should be sweet and ready about three weeks later. But don't guess—carefully pull back the tip of a sample husk and pierce a kernel a few rows down. If the liquid inside is milky white, take a confirmation bite. If it's sweet, get the water boiling!

Growing a 'double-duty' variety also takes the angst out of possibly missing that harvest window. If you fail to pick in time, just allow the ears to dry on the plant and you'll have ornamental corn to display at Halloween and Thanksgiving—and to make tasty corn bread and muffins with over the winter.

Now, I seem to remember somebody asking about food….

Oh yeah! That was you, Greg! Corn is the most nitrogen hungry crop we grow and one of the few plants that may need more food than compost alone can provide. I recommend you plant the seed in flat ground (not raised beds, where corn tends to fall over) after the soil is warm, wait until the plants are about six inches tall and then shovel lots of compost in between the rows to supply some early nutrition and keep weeds down. (Don't feed AT planting time; seeds ARE food.)

Follow this a few weeks later with something very nitrogen rich, like composted poultry manure or corn gluten meal. You want a natural product with nitrogen levels between 8 and 12 (any higher than that and they can't BE natural). Nitrogen is the first number on that three-number set required by law on any packaged fertilizer, natural or chemical.

Q. This past summer I tried gardening for the first time. My father had always organically-grown sweet corn for us in the summer, and I loved it. So I bought a bunch of packets and planted a dozen rows, two feet apart and 20 feet long, with different varieties in adjacent rows. I gave them Miracle-Grow every other day until they sprouted, then kept them well weeded, and thinned to about 2-3 inches between plants. I wound up with very few good ears of corn. Some ears only had a few kernels, and the majority were tiny and misshapen. What could cause this?
    ---James in Monroeville, NJ
A. Eh, in your case, everything! I'm shocked you got ANY good corn, James!

First, you don't feed seeds. If you're foolish enough to use chemical salts like Miracle-Gro (which I do NOT recommend and which made your sweet corn NON-organically grown), at least wait until the plants have sprouted and developed true leaves. 'Seed' is mostly food. Same with an organic fertilizer; wait to apply it until after the plants are up.

Unfilled ears are lack of adequate pollination; you simply didn't have enough plants of the same variety pollinating at the same time. You should always grow as many plants of the same variety at the same time as your space allows, so that the largest amounts of the right kind of pollen are flying around at silking time. The minimum is 36 plants—six rows of six—to get decent sized ears; a hundred plants is more like it if you want a high-quality harvest. (Don't worry about having too much all at once; sweet corn freezes brilliantly.)

There are also several different basic types of sweet corn—'normal', 'sugary enhanced' and 'supersweet', which can also cancel out each other's sweetness if they pollinate at the same time. One variety a year sounds better all the time, doesn't it?

Your weeding may also have damaged the roots; that's why I recommend a mulch of compost to control weeds. And finally (well, not really, but we're running out of time), your plants were really crowded; 6 inches to a foot between plants is more like it.

All this adds up to the sad fact that corn is not the ideal choice for a small space garden (and people say I'm slow to catch on!). It is a hog of space, sun, water and food....

...But if you have the room, there's nothing that can rival those first candy-sweet ears of a superb variety like Platinum Lady, Kandy Korn or Ambrosia, picked after the water has already come to a boil, lightly cooked, rolled in butter and black pepper, and….ahhhh!

You know, I could take down a couple of trees to make some more room at my place…

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