Sweet Corn

Growing Conditions

Sweet corn needs warm soil (60°F minimum for standard types, 65°F for supersweet varieties) and full sun. It is wind-pollinated — plant in blocks rather than long single rows for adequate pollination. Poor pollination produces ears with missing kernels. Requires consistent moisture during tasseling and ear fill.

Cold climates: Direct sow after last frost once soil has warmed. Succession plant every 2 weeks for extended harvest. Choose varieties with 75 days or fewer for reliable harvest in Zone 5.

Warm climates: Multiple successions possible through summer.

Sowing & Planting

Sow 1 inch deep, 8–12 inches apart, in blocks of at least 4 rows to ensure wind pollination. Rows should be 30 inches apart. Isolate supersweet varieties from standard and sugary-enhanced types by 250 feet or 2 weeks in timing — cross-pollination causes starchy, poor-flavored kernels.

Care & Maintenance

Water consistently — critical during tasseling (when pollen sheds) and ear fill. Drought at these stages causes poor kernel development. Side-dress with nitrogen-rich fertilizer when plants are 12 inches tall and again at knee height. Corn is a heavy nitrogen feeder — plant after legumes if possible.

Common Problems

Corn earworm is the most common pest — larvae feed inside the ear tip. Apply a few drops of mineral oil to the silk just after it wilts to prevent entry. European corn borer tunnels into stalks and ears. Raccoons are a significant problem at harvest — they know exactly when corn is ripe. Row cover or electric fence are the most effective deterrents. Poor ear fill results from inadequate pollination — plant in blocks.

Harvest

Harvest when silk has dried and browned, and kernels are plump — pierce a kernel with a fingernail; milky juice indicates peak ripeness (clear = too early, thick/doughy = too late). Pull ears downward with a sharp twist. Cook or freeze within hours — sugar converts to starch rapidly, and the difference between hours-old and day-old corn is noticeable.

Varieties

Standard sweet corn (Silver Queen, Peaches and Cream) is reliable and easy to grow but converts to starch quickly. Sugary-enhanced (SE) types (Sugar Buns, Kandy Korn) are sweeter and hold quality longer. Supersweet (SH2) types (Supersweet Jubilee, Garrison) are very sweet and hold quality longest but need warm soil for germination and must be isolated. For most home gardens, an SE variety balances sweetness, ease of growing, and harvest flexibility well.