How to Grow Corn From Seed

Corn is a warm-season crop that rots in cold, wet ground, so there is no rushing it. Direct-sow seeds outdoors 1 to 2 weeks after your last frost, once the soil has warmed to at least 60F, and closer to 65F for the sweetest supersweet types. Corn does not transplant well, so sowing straight into the garden is best. For a longer harvest, sow a fresh block every two to three weeks until about 90 days before your first fall frost.

Plant corn in a block, not a single long row, because it is pollinated by wind and needs neighbors close by. Sow seeds 1 to 2 inches deep and 4 to 6 inches apart in at least four short rows set 24 to 36 inches apart, in rich soil and full sun. Keep the bed evenly moist and seedlings appear in 7 to 10 days at 60F or warmer. Thin the young plants to stand 8 to 12 inches apart so each stalk has room to grow.

Corn is a heavy feeder and a thirsty one. Work plenty of compost or a nitrogen-rich fertilizer into the bed before planting, then side-dress again when the stalks are knee-high and once more when the tassels form. Give a steady inch of water a week, and never let it go dry while the plants are tasseling and filling ears. In hot, dry regions like the Southwest, mulch heavily and water deeply to keep pollination from failing; in cooler areas like the northern Midwest or New England, choose an early-maturing variety and wait for warm soil before sowing.

Corn grows well beside plants that draw in pollinators, cover the bare soil at its feet, or lure pests away from the stalks. These three make good neighbors for a corn patch, and you can add any of them in one click:

Sweet corn is ready about three weeks after the silks appear, usually when the silks have turned brown and dry and the husks feel full and firm. Peel back a bit of husk and press a kernel with your thumbnail: a milky juice means it is ready, clear juice means wait, and a doughy paste means it is past its best. Pick in the cool of the morning and cook or chill it fast, because sweet corn starts turning its sugars to starch the moment it leaves the stalk.

Fresh sweet corn is best eaten the day it is picked. Boil or grill the ears and eat them on the cob with butter and salt, or cut the kernels off for salads, salsa, chowder, and cornbread. Extra corn freezes well once blanched, either on the cob or as loose kernels, so a big block can feed you well past the summer.

• Half-filled or gappy ears: poor pollination, usually from planting in a single row. Plant in a block of at least four short rows and water steadily while tasseling.
• Toppling stalks: wind rock or shallow roots. Hill soil up around the base as plants grow and avoid over-crowding.
• Chewed kernels at the ear tip: corn earworm. Squeeze a few drops of vegetable oil onto the silks once they brown, or grow varieties with tight husks.
• Pale, stunted plants: hungry soil. Corn is a heavy feeder, so side-dress with a nitrogen-rich fertilizer when knee-high and again at tasseling.