B. Rosie Lerner
Purdue Extension


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"A Maizing" Sweet Corn

Nothing tastes better than homegrown corn, but, because of its demand for space, sweet corn has traditionally belonged to the domain of large country gardens. Sweet corn plants usually produce only one ear per stalk, possibly two. And because a lot of corn pollen is needed to get a full ear, a large block of plants is usually required to ensure good yields. Poor pollination results in poorly filled ears.

But, if you have a limited amount of space, you can plant your corn in short blocks rather than long rows. Or try planting seed in hills. Start with three seeds per hill and thin to two plants after germination. Corn pollen is distributed by wind, rather than insects, so manually shaking the stalks when plants are in tassel may help distribute the pollen.

Modern sweet corn cultivars have been bred to have greater sugar content and a slower conversion of that sugar to starch. This not only means sweeter produce, but also the ability to hold that quality longer, whether it is in the supermarket, in your garden or in your refrigerator.

Sweet corn can adapt to any well-drained soil but requires warm soil for quick germination. Standard sweet corn seeds can be planted about 10 days before the average last frost date. The newer supersweet-, triplesweet- or sugary-enhanced-type sweet corns are even more demanding of warm soils and should not be planted until soil temperatures have reached greater than 60 F, usually safe by mid May most years. But this year our temperatures have been up and down considerably, so timing sweet corn planting has been difficult.

Start out with freshly purchased seed each year since sweet corn is relatively short-lived, even under ideal storage conditions. Spotty, non-uniform germination generally leads to inadequate pollination. Replanting seed for skipped plants is also ill advised since the plants won't mature to produce pollen at the same time.

Since corn is wind-pollinated, sweet corn should not be planted near field corn, ornamental corn or popcorn, unless you can be sure they won't be in flower at the same time. Pollen from these other types of corn will make sweet corn kernels starchy. Some of the sweet-type corns must also be isolated from other sweet corns as well. If you're planting more than one cultivar of corn, check the seed packet for pollination restrictions. You can stagger your planting dates or use early- and late-season cultivars to keep the different types of corn from being in bloom at the same time.

For more information about growing sweet corn, see Purdue Extension publication HO-98-W online at or contact the Purdue Extension office in your county.



Writer: B. Rosie Lerner
Editor: Olivia Maddox