Corn is a warm-weather crop, so don’t rush planting in spring: Seeds planted in soil cooler than 65°F will simply rot. Plant at least 2 weeks after the last frost in loose, fertile, well-drained soil. If you plant just a few long, single rows, you won’t get much corn, because pollen must be transferred from the tassels (held atop the plants) to the silks (held lower down). A stiff wind can send pollen flying far beyond its mark, so you should always plant in blocks of at least five rows deep.
Before planting, work into the soil 1 cup of 10-10-10 or 10-14-10 fertilizer per 10 ft. of row. Plant seeds 1 in. deep (¾ in. deep for supersweet types), in rows spaced 2–3 ft. apart. Most types are capable of producing two or more ears per stalk. However, rows planted less than 2 ft. apart generally yield one ear per stalk. When seedlings are 6 in. tall, thin them to 1 ft. apart. To extend the harvest, make three or four more plantings at 2-week intervals—or plant early, midseason, and late selections.
Watering and Feeding
Regular watering is critical, especially when tassels are being formed. Drought-stressed plants produce puny ears with missing kernels. Corn has a hefty appetite. Fertilize plants when they’re 8 in. tall and again when they’ve reached 18 in.; each time, apply ½ cup of controlled-release 10-14-10 fertilizer per 10 ft. of row.
Check your crop when the ears are plump and the silks have withered; corn is usually ready for harvest 3 weeks after the silks first appear. To test, pull back the husks and try popping a kernel with your thumbnail. It should squirt milky juice; watery juice means that corn isn’t ready to eat.
Corn earworm is the principal insect pest. There is no simple control. Most gardeners expect some ears to show worm damage at the silk ends, and they just cut off those ends. The prevention (it’s tedious) goes like this: 3 to 7 days after silks appear, use a medicine dropper to put two drops of mineral oil just inside the tip of each ear. As an alternative, plant selections with tight husks that discourage earworms; these include ‘Country Gentleman’, ‘Hickory King’, and ‘Texas Honey June’.