How to grow Sweet Corn

At a glance

🌱 Grow your Sweet Corn with GardenDex

• Reminders to water it, timed to your weather and whether it's in a pot
• Frost and disease alerts for your garden, the night before
• Follow it from seed to harvest, and see what your garden grew in $
• Point your camera at any plant or bug to identify it

🗓️ When to plant

Sow seeds in mid-spring after the last frost, when soil has warmed to at least 15°C (60°F). For continuous harvests, sow every 2 to 3 weeks until mid-summer.

🌰 How to plant

1. Soak seeds overnight to speed germination.
2. Push seeds 2 to 3 cm (1 in) deep into warm, moist soil.
3. Thin seedlings to 30 cm spacing once they're 10 cm tall.
4. Provide support with stakes or cages if growing in windy areas.

💧 Care

• Water deeply at the base to keep soil evenly moist during growth and silking.
• Mulch around plants to retain moisture and suppress weeds.
• Side-dress with nitrogen-rich fertiliser when plants are knee-high and again at silking.
• Remove lower leaves once tassels appear to improve air circulation and reduce disease risk.
• Plant in blocks of at least 4 rows for effective wind pollination of ear development.

🧺 Harvest

Pick ears when husks are bright green, silks are brown and dry, and kernels release milky liquid when pierced with a fingernail. Harvest in early morning for maximum sweetness and store in the refrigerator immediately.

🐛 Common problems

Corn borers: Remove affected plant parts and apply neem oil or use row covers on young plants; plant resistant varieties if available.

Powdery mildew: Improve air circulation by pruning lower leaves, avoid overhead watering, and apply sulphur spray if needed.

Poor ear development: Ensure consistent watering and nitrogen feeding, and plant in blocks for better pollination by wind.

🤝 Companion plants

💚 Good neighbours: Beans, Pumpkins, Cucumbers, Lettuce

⚠️ Keep apart from: Brassicas, Fennel, Tomatoes

More vegetables guides