How to grow sweet corn

Zea mays subsp. mays · Poaceae · Vegetable

Sweet Corn is a warm-season vegetable in the Poaceae family, almost always sown straight into the ground where it will grow. It wants full sun (six or more hours of direct light) and plenty of water, especially in hot weather. From sowing to first pick is about 60–100 days. It is killed by frost, so nothing goes outside until the danger has passed and the soil has warmed.

Grower’s note: Plant in a block of at least 4 short rows, not one long row, or the ears fill unevenly. Keep sugar-enhanced and supersweet types isolated from field corn. Succeed by sowing every 2 weeks or planting early/mid/late varieties together.

Sowing

Sow about 1.5″ deep, into soil between 55–95°F — germination is quickest near 75°F. It comes up fast (5–12 days). It does not transplant well, so sow it in its final position rather than starting it in pots.

Spacing & layout

Give each plant about 10″ along the row with roughly 30″ between rows. On a square-foot grid that is 1 per square foot. Allow at least 24″ of loose, workable soil for the roots. It needs more root room than most containers give and does best in the ground.

Fitting it to your season

Sweet Corn needs roughly 60–100 frost-free days to crop. Where the season is shorter than that, start it indoors and choose the earliest-maturing varieties, or grow it in a container you can move under cover on cold nights. In long, hot-summer regions it can often be planted twice — once in spring and again in mid-to-late summer for a fall harvest.

Quick facts

When to plant sweet corn

Companions

Common problems

Pests: corn earworm, European corn borer, corn rootworm, raccoons.

Diseases & disorders: common smut, common rust, Stewart's wilt.

Figures are typical home-garden ranges from Cooperative Extension planting guides, cross-checked against multiple state sources. Your variety and conditions will vary.