How to Grow Corn

Growing guide

Overview

Corn is a warm-season annual grass grown for sweet ears that are best eaten right after picking. Home growers love it for its fast growth and garden-fresh sweetness. It needs full sun, rich well-drained soil, consistent moisture, and block planting so wind can pollinate the silks.

Soil & planting prep

Plant corn in loamy, well-drained soil enriched with compost or aged manure; it grows best in a slightly acidic to neutral pH of about 5.8-7.0. Sow seeds 1-2 inches deep and 8-12 inches apart, leaving 30-36 inches between rows if you use rows.

When to plant

Direct sow corn only after your last frost date has passed and soil has warmed to at least 16°C (60°F). Corn is frost-tender and is not a fall-planted crop, and it transplants poorly, so it is direct-sowed in place.

How to plant

1. Choose a full-sun site and work 1-2 inches of compost or aged manure into loamy, well-drained soil.
2. Wait until after the last frost date and soil temperature reaches at least 16°C (60°F).
3. Sow seeds 1-2 inches deep and 8-12 inches apart in a block of at least four short rows rather than one long row.
4. Water the bed deeply after planting and keep soil evenly moist, especially as seedlings establish.
5. Side-dress with a nitrogen-rich fertilizer when plants are 12-18 inches tall.

5 common mistakes to avoid

• Planting in a single long row instead of a block leads to poor pollination and ears with missing kernels because corn is wind-pollinated; plant at least four short rows of four or more plants.
• Direct sowing before soil reaches 16°C (60°F) invites seed rot and weak germination; wait until after the last frost date and until soil has warmed.
• Letting soil dry out during tasselling and silking causes poor kernel fill and stubby ears; give corn deep, consistent water especially from tassel emergence through ear fill.
• Growing a supersweet variety too close to another corn type can produce tough or starchy kernels from cross-pollination; isolate sweet types by distance or stagger maturity.
• Leaving sweet corn on the stalk too long after silks brown turns sugars to starch; harvest when a pressed kernel releases milky liquid.

Harvesting & storage

Corn is ready about 18-24 days after silks appear, when the silks are brown and dry. Peel back a small husk section and press a kernel; it should release a milky liquid. Harvest by twisting the ear downward, then eat or refrigerate immediately before sugars turn to starch.

Companion planting

Beans and squash are classic companions: pole beans can use the stalks for support, and squash shades the soil. Avoid planting corn near tomatoes, which share the corn earworm/tomato fruitworm pest.

Growing in containers

Corn is not container-friendly; it needs a block of plants for wind pollination and strong root anchorage. Grow it in the ground rather than in pots or balcony containers.

Pro tips

Direct sow after soil reaches 16°C. Plant in a 4x4 block minimum for wind pollination. Needs consistent water especially during tasselling. Not suitable for containers.