Description
Corn is a tender, warm-season annual crop that produces ears of yellow, white, or bi-colored kernels. It is a member of the grass family (Poaceae) and relies on wind to pollinate its flowers. This is the reason that corn is planted in blocks of short rows instead of long, single rows. There are several varieties of sweet corn. Corn plants can grow up to 6 feet tall and have long, narrow leaves. In Sri Lanka, corn is grown in various regions and is an important crop for both human consumption and animal feed.
Planting requirements
Planting season: October to January and April to August
Planting conditions:
| Propagation | Propagate from seeds or transplant |
|---|---|
| Planting method | Wrap the seeds in a moist cloth/paper towel for 24 hours before planting for germination. Sow seeds about 1Β½ to 2 inches deep and 2 to 4 inches apart in short, side-by-side rows to form a block, rather than one long row |
| Soil | Requires deep, well-drained, humus-enriched loam. Needs a soil pH of 5.8 to 7. It requires nitrogen-rich soil as it is a heavy feeder, apply compost or manure before planting |
| Water | Needs consistent moisture in the soil and it should be well drained. Water well at planting time, ensure soil remains moist but not waterlogged. In dry zones, consider mulching to retain moisture |
| Light | Plant in full sun (at least 6 to 8 hours of direct sunlight), consider providing some shade during peak heat hours for better pollination |
Growing conditions:
| Temperatures | Daytime temperatures should ideally be between 20-30Β°C (68-86Β°F) |
|---|---|
| Soil | As the roots are deep and widespread, the plant requires plenty of humus. A couple of inches (5 cm) of well-rotted manure dug well in a spit deep is ideal, consider using organic fertilizers for better growth |
| Water | Corn plants are large and fast-growing vegetables and need regular feeding and watering. Increase watering as the crop grows, and apply liquid fertilizer every 2-3 weeks during the growing season |
| Pruning | Not applicable |
| Weed control | Keep in mind that corn is shallow-rooted, so stay away from deep cultivation, and consider using mulch to suppress weeds and retain moisture |
Harvesting
Test for ripeness by opening the husk and pressing your fingernail into a grain, if it is firm but still slightly milky it is ready. Pick the corn by jerking the cob sharply downwards and breaking it off. To avoid the risk of damaging the plant, do not cut them off.
Curing
Corn does not require a curing stage.
Storage
Do not wash corn while it's still in the husk before storing. Keep the corn in its husk and refrigerate. Once you're ready to prepare it, remove the husk and silk, then rinse the corn under cool running water. Store it for up to 12 months for optimal preservation.
Protecting your plants
Pest control
Pest types:
- African Maize Stalk Borer (Busseola fusca)
- Fall Armyworm (Spodoptera frugiperda)
- Corn Leaf Aphid (Rhopalosiphum maidis)
- Lesser Cornstalk Borer (Elasmopalpus lignosellus)
- Earworm (Helicoverpa zea)
Symptoms:
- African Maize Stalk Borer: Holes and "windows" in leaves, small dark caterpillars at leaf base, central leaf death, stem damage
- Fall Armyworm: Wilting, ragged holes in leaves, cob damage
- Corn Leaf Aphid: Yellowing of leaves, stunted growth
- Lesser Cornstalk Borer: Holes in seedlings, wilting, stunted growth
- Earworm: Bore into the tips of the ears of corn
Control methods:
- Earworm: If seen when you pick the corn, destroy them.
In general;
- Deep summer ploughing
- Intercropping with cowpea
- Release natural predators (e.g., Trichogramma chilonis)
- Use pheromone traps for monitoring
- Apply neem seed kernel extract
- Early planting
- Crop rotation
- Destruction of crop residues
- Use resistant varieties
Disease Control
Disease types:
- Maize Dwarf Mosaic Virus (MDMV)
- Head Smut (Sphacelotheca reiliana)
- Maize Stripe Disease
- Stewart's Wilt
Symptoms:
- MDMV: Light and dark green mottles on leaves, mosaic patterns, stunted growth, poor ear fill
- Head Smut: Black masses on tassels and ears, deformed grains
- Maize Stripe Disease: Narrow yellow stripes on leaves, poor ear development
- Stewart's Wilt: Wilting leaves, stunted growth
Management:
- Plant resistant varieties
- Manage aphid and leafhopper populations
- Practice crop rotation
- Remove infected plants
- Control flea beetle populations
- Use resistant hybrids
- Apply insecticides or biological control methods as needed
Sources
In addition to our General List of Sources (link), we used these specific references:
