Sweet Corn

Grow your own sweet corn this summer!

By Gretchen Roberts


In the Hills
Soil preparation:
Corn has fairly shallow roots, and it uses a lot of nitrogen and other soil nutrients. To help your crop get off to a strong start, prepare the soil first with a nitrogen-rich fertilizer such as chicken manure or compost (use about 20 to 30 pounds for 100 square feet).

Site. Plant in the southwest side of the garden so the tall corn plants won't shade out the rest of your crops (or grow corn where it will shade greens and other plants that cannot tolerate direct summer sun).

No rows. Corn is wind-pollinated, so a square plot is more effective than long rows and it can help you use limited space efficiently. The Zuni Native Americans of the Southwest plant corn in hills in a square. Sow four to five seeds in hills, leaving 3 to 4 feet between each hill and making a square, advises George Dickerson, an extension horticulture specialist at New Mexico State University. Thin the seedlings to three or four in each hill by cutting the extra seedlings at ground level. Even in a small plot, the square formation ensures pollination no matter which direction the wind blows.

Timing. Corn germinates best in soil that's warmer than 60°F. Corn seed sown in cold, moist soil is susceptible to fungal disease, says Rosie Lerner, extension specialist at Purdue University. "When in doubt, wait," she advises. If you have a short growing season or just want to get your corn off to a quick start, try pregerminating seeds indoors in biodegradable pots (corn doesn't transplant well). Or warm the soil by covering it with clear or black plastic for a week or more so the sun can raise its temperature.

Succession. If you want a few harvests of corn, plant early, midseason, and late varieties in early summer, or plant your favorite variety every 2 weeks for 6 weeks. Beware of cross-pollination of different varieties, which can result in tough, starchy kernels. Be particularly careful to isolate the supersweet varieties by time (timing your plantings so that the supersweets are not shedding pollen at the same time as other varieties) or space (200 to 400 yards between varieties).

Saving space. Plant corn together with pole beans and vine crops like cucumbers, squash, and pumpkins, suggests Pete Ferretti, professor of vegetable crops extension at Penn State University. "Pole beans and vine crops planted on the sunny side of a row of corn will grow up the stalks, which doesn't hurt the corn."