Growing Sweet Corn
- Seasons of growth: Corn is a warm season annual that enjoys full sun and fertile, well-drained soils.
- Frost tolerance: Frost will damage corn at any stage of growth. Corn should not be planted until after the last frost in your area, and it’s best to hold off until both soil and air temperatures have reached at least 60°F.
- Plant Height: 4-8 feet tall
- Plant Width: 1-3 feet wide
- Plant Spacing: Utilize 3-4 ounces of seed per 100 foot row of intended plants. To establish better pollination and production, plant in blocks of rows rather than in one long row. Place seeds 1-2 inches deep in the soil, 9-12 inches apart in rows 24-30 inches distant from one another. For a high density crop, plant in square of 15×15 inches. To ensure continuous production, plant seeds every 10-14 days until early July.
- Germination Requirements: Seeds require soil temperatures of 60-95°F, and should germinate in 4-12 days.
- Best establishment method: Corn does not transplant well, making seeding the best method of establishment.
Cultivation and Harvest
Water plants regularly, soaking soil to near field capacity. Plants especially require water during phases of tasseling, silking and ear formation. Stress caused by drought will lower yield, kernel quality and have a negative effect on flavor. Note that the amount of water plants receive depends on soil type. For example, heavy clay soils will not need to be watered as often as sandy soils.
Fertilization Requirements and Recommendations
Before planting prepare the bed with 2-4 inches of well-drained, fertile organic compost as well as 1-2 lbs of all-purpose fertilizer (16-16-8) for every 100 square feet. Both should be worked into the top six inches of the planting area.
Corn will need additional fertilization when plants have acquired 8-10 leaves and again when the first silks appear. For the first application, apply ½ lb of 21-0-0 for every 100 square feet, and then ¼ lb when silks emerge. Fertilizer should be placed 6 inches to the side of the plant and irrigated into the soil.
Days to Harvest: Depending on variety, corn generally takes about 60-90 days to mature.
Diseases and Control
When cultivating corn, be aware that plants may suffer from root rots or damping off, smut and wilt diseases. Use seed treated for root rots and allow soils to dry slightly before re-watering to avoid this problem, which may cause seedlings to wilt and die. Smut can be identified by the white fungal galls that form on the tassel, stem or ear.
Galls must be removed and any plants that are severely infected destroyed. Select and plant resistant varieties. To avoid wilt disease, maintain clean garden practices. Remove infected plants, which may have wilting leaves, dry or rotting stalks and streaking.
Insects and Control
Corn may attract the attentions of aphids, cutworms or army worms and corn earworms. Aphids can be controlled with the insecticidal soap and dislodged with a strong stream of water. Corn earworms, which feed on ears, can be controlled with BT or a similar natural insecticide.
Apply regularly to ensure the plants remain protected. Mineral oil applied to the silks is also used to treat this problem. Cutworms or army worms work at night, feeding on lower parts of the plant. These can be kept away with barriers or collars around the plants.