11 Common Corn Growing Problems And How To Fix Them
Practical gardening tactics to nurture robust stalks and fuller ears in a backyard patch.
Corn is a rewarding but sometimes challenging crop for home gardeners. From inadequate pollination to hungry pests and mysterious diseases, many factors can impact your harvest. Below you’ll find an in-depth guide to the 11 most common corn growing problems, their causes, and strategies for prevention and correction.
Table of Contents
- Leaf Problems
- General Plant Issues
- Problems with Pollination
- Pest Problems
- Disease Problems
- Environmental Stress
- Other Common Issues
- Frequently Asked Questions
To tackle issues with moisture management in your garden, consider exploring our Essential Guide to Troubleshooting Zucchini Problems. This resource provides practical insights that can help ensure your plants thrive, especially during challenging climates.
Leaf Problems
1. Leaves Rolling Inward or Curling
Symptoms: Corn leaves that roll or curl inward, especially during daytime or heat.
- Causes: This is usually a response to insufficient soil moisture or extreme heat. Rolling helps the plant conserve water but also signals stress.
- Solutions:
- Water deeply and consistently. Check moisture at least four inches below the surface and water as needed.
- Mulch heavily around the base to conserve soil moisture.
- Avoid watering during peak sun to minimize evaporation.
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2. Yellowing, Spotting, or Streaky Leaves
- Causes: May result from nutrient deficiencies (particularly nitrogen), water stress, or certain fungal diseases.
- Solutions:
- Apply a well-balanced fertilizer, focusing on nitrogen during early growth.
- Remove affected leaves if disease is present and increase airflow.
- Practice crop rotation to avoid soil-borne pathogens.
General Plant Issues
3. Small Ears or Underdeveloped Cobs
Symptoms: Mature plants with safe-sturdy stalks, but ears are thin, short, or missing kernels.
- Causes:
- Poor nutrition — inadequate soil fertility or lack of key nutrients like nitrogen and potassium.
- Improper plant spacing resulting in overcrowding or competition for resources.
- Weak or incomplete pollination.
- Solutions:
- Space plants 9-12 inches apart in blocks at least 2 rows deep to improve pollination and airflow.
- Apply fertilizer at planting and again mid-season for nutrient support.
- Consider a soil test to check for potassium or nutrient deficiencies, and supplement as needed.
4. Stunted or Poor Growth
- Causes: Poor seed quality, compacted or waterlogged soils, low temperatures at planting, lack of sun, poor fertilization, or root damage.
- Solutions:
- Select high quality, fresh seed and plant after soil is thoroughly warm (typically above 60°F/16°C).
- Prepare soil well before sowing — break up compaction and add compost.
- Ensure the site receives full sun (at least 6-8 hours/day).
Problems with Pollination
5. Poor or Incomplete Pollination
Symptoms: Cobs with missing or uneven kernels; tops of ears bare or incompletely filled.
- Causes:
- Insufficient planting density—corn is wind-pollinated and needs to be planted in blocks rather than single rows to ensure adequate pollen transfer.
- Adverse weather—hot/dry winds during silking damage pollination.
- Improper timing or spacing of different varieties, leading to pollen drift or incompatibility.
- Solutions:
- Always plant corn in blocks of at least 3-4 short rows rather than a single long row.
- Hand-pollinate by shaking the tassels over silks in small gardens.
- Stagger sowing times or plant one variety per block to avoid cross-pollination issues.
- Keep the area evenly moist during pollination to help pollen stick to silks.
Pest Problems
6. Caterpillars, Worms, and Moth Larvae
Common Culprits: Corn earworm, armyworm, cutworms, fall armyworm, European corn borer.
| Pest | Symptoms | Control Measures |
|---|---|---|
| Corn Earworm | Visible frass (waste) and chewed tips; larva inside kernels at tip. | Spray silks with organic insecticide every 3–5 days from early silking until brown; opt for early-maturing corn varieties. |
| Cutworm | Seedlings cut down at soil line, especially at night. | Use collars around stems, till soil before planting, clear plant debris. |
| Armyworm | Irregular holes in leaves; masses of caterpillars during outbreaks. | Introduce beneficial nematodes, keep area weed-free. |
| European Corn Borer | Boring into stalks; wilted or broken stems. | Remove infested stalks, ensure winter cleanup, rotate crops. |
7. Aphids and Other Sap Suckers
- Symptoms: Sticky residue (honeydew) on leaves, yellowing, stunted growth, leaf curling.
- Control Measures:
- Use strong water sprays to dislodge aphids.
- Apply insecticidal soap or neem oil if infestations persist.
- Attract natural predators like ladybugs.
8. Vertebrate Pests: Birds, Raccoons, Squirrels
- Symptoms: Missing or damage to ripening ears, knocked down stalks.
- Prevention and Solution:
- Protect maturing corn with netting, row covers, or temporary fences just before harvest.
- Harvest promptly once ears are ripe.
Disease Problems
9. Common Fungal Diseases
| Disease | Symptoms | Control Measures |
|---|---|---|
| Corn Smut (Ustilago maydis) | Gray to black, swollen galls on ears, stalks, and leaves. | Remove and destroy galls before they rupture; rotate crops; destroy old stalks after harvest. |
| Northern Corn Leaf Blight | Gray, cigar-shaped lesions; leaves become ragged and tattered. | Choose resistant varieties; remove affected tissues promptly. |
| Common Rust | Red-brown pustules on leaf surfaces; leaves may yellow and die back early. | Resistant corn varieties provide best protection; rotate crops annually. |
- Keep foliage dry and provide ample airflow by following ideal spacing guidelines.
- Promptly remove affected plants or tissues and avoid overhead irrigation where possible.
Environmental Stress
10. Drought, Flood, and Unseasonable Weather
- Drought: Leaves curl, ears are stunted, and poor pollination.
- Flood/Waterlogged Soil: Roots suffocate, growth is stunted, yellowing, increased risk of disease.
- Cold Weather: Slow sprouting, weak seedlings, yellowing leaves.
Solutions:
- Water consistently and deeply, especially when tassels and ears are forming.
- Improve soil drainage with organic matter to reduce waterlogging.
- Use mulch to conserve moisture and stabilize temperature.
- Monitor temperature and avoid planting until soil is warm.
11. Other Common Issues
- Root Damage or Compaction: Avoid stepping near the base or overworking wet soils.
- Improper Seeding Depth: Sow kernels about 1-1.5 inches deep for best emergence. Too deep or shallow can hinder sprouting.
- Mulching Mistakes: While mulching is useful, avoid too-thick layers in wet climates, which can harbor disease and pests.
- Untimely Harvesting: Corn left on the stalk too long may lose quality or attract pests; harvest promptly as soon as the silks turn brown and kernels are plump.
Frequently Asked Questions (FAQs)
Q: Why are some of my corn ears missing kernels or looking scraggly?
A: This is usually caused by incomplete pollination, either due to planting in single rows, drought stress during silking, or extreme heat. Plant in blocks and keep soil moist during tassel and silk formation.
Q: What is the best way to control corn earworm?
A: Use early season corn varieties and spray organic insecticides directly onto silks when they first emerge. Harvest promptly when cobs are ripe.
Q: How often should I fertilize my corn?
A: Fertilize once a month after transplanting and again at midseason using a balanced fertilizer. Soil tests can help tailor your strategy if problems persist.
Q: My plants are healthy, but ears are still small. What gives?
A: Small ears with good foliage usually indicate a lack of nutrients at key development stages or insufficient water. Top-dress with fertilizer midseason and water deeply during ear development.
Q: Is it possible to avoid all pests and diseases without chemicals?
A: You can minimize issues by selecting resistant varieties, practicing crop rotation, keeping your garden clean, and using organic controls like neem oil or insecticidal soap.
Quick Reference Table: Corn Growing Troubleshooting
| Problem | Probable Cause | Solution |
|---|---|---|
| Leaf curl or rolling | Drought or root stress | Water deeply; mulch generously |
| Small or misshapen ears | Poor pollination, overcrowding, low nutrients | Plant in blocks; space correctly; fertilize |
| Kernels missing | Lack of pollination, heat, drought | Keep soil moist; hand-pollinate; plant in blocks |
| Pest-infested ears | Corn earworm, birds, raccoons | Spray silks; use covers; harvest promptly |
| Fungal galls | Corn smut fungus | Remove and destroy galls; crop rotation |
| Poor growth | Low temperature, compacted soil, low sun exposure | Warm, friable soil; full sun |
Key Takeaways for a Strong Corn Harvest
- Plant in blocks, not rows, for proper pollination.
- Space correctly (9-12 inches apart) to prevent resource competition.
- Mulch and water consistently, especially during tassel and silk development.
- Use resistant corn varieties to preempt common diseases.
- Monitor for pests and protect ripening cobs until harvest.
- Rotate crops, clean up debris, and destroy any infected plant material each season.
Further Resources
- Local agricultural extension offices
- Authoritative gardening books on vegetable crops
- Soil test kits and guides
- Organic pest control solutions
References
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