Why Are My Green Bean Leaves Turning Yellow? 7 Potential Causes and Fixes

Growing green beans can be a rewarding experience producing bountiful harvests of delicious fresh beans. However it can be concerning when the leaves start turning yellow instead of staying green and healthy. Yellowing leaves are often a sign of stress or disease.

There are several potential culprits that could be causing the yellowing. By identifying the specific reason, you can take the proper corrective steps to restore your plants to vigor. Here are 7 common causes and fixes for yellow leaves on green bean plants:

1. Improper Watering

Inconsistent watering is one of the most frequent reasons for yellow bean leaves. Both overwatering and under-watering can induce leaf yellowing

With underwatering, the plant is unable to take up adequate moisture and nutrients from the soil. Overwatering suffocates the roots, again depriving them of oxygen and nutrients. Stunted growth and yellowing leaves ensue in either case.

Fix: Check soil moisture before watering. Insert your finger 1-2 inches deep to see if the soil is dry. Water thoroughly if needed until drainage emerges from bottom, then allow soil to partially dry out before next watering. Green beans need about 1-2 inches of water per week.

2. Insufficient Sunlight

Green beans require at least 6-8 hours of direct sunlight daily for robust growth. Without adequate light, the leaves are unable to photosynthesize sufficiently and will turn yellow. Lower leaves may yellow first if shaded by upper foliage.

Fix: Ensure beans receive full sun, especially from mid-morning through mid-afternoon. Move plants or thin foliage to improve light penetration. New growth should emerge green if adequate sunlight is provided.

3. Extreme Temperatures

Green beans thrive in warm weather, with optimal temperatures between 70-80°F. Prolonged exposure to cold temps below 60°F or excess heat over 90°F can induce yellowing of established leaves. Beans also need properly warmed soil (at least 50°F) for planting.

Fix: Use season extending techniques like cold frames, cloches or row covers to protect from frost and extreme cold. Provide shade in peak summer heat. Use mulch to moderate soil temperature. Choose weather-appropriate planting times.

4. Improper Soil Conditions

Beans prefer loose, well-draining soil with a pH between 6.0-7.0. Poor drainage can waterlog roots while overly dry, dense, or high clay soil restricts development. Extreme pH also limits nutrient availability.

Fix: Incorporate compost or other organic material to improve soil structure and nutrients. Test and amend pH if needed. Mulch to retain moisture and reduce watering frequency.

5. Nutrient Deficiency

If yellowing occurs but veins remain green, nutrient deficiency may be the cause. Lack of nitrogen is most common, but beans also need adequate levels of iron, zinc, manganese and magnesium for vigor.

Fix: Test soil and apply a balanced organic fertilizer as needed at planting and midseason. Compost and manure will also provide nutrition. Go easy on high nitrogen fertilizers.

6. Root Damage

If beans are planted in too small a container, the restricted roots can’t deliver sufficient water and nutrients, causing yellowing. Underground pests like wireworms can also damage roots.

Fix: Transplant to larger containers or beds with loose soil and adequate depth for root development. Inspect for pests and treat as needed.

7. Disease

Fungal, bacterial and viral diseases can also cause yellowing. Common culprits include:

• Anthracnose – circular brown spots on leaves with yellow borders.

• Bacterial blights – angular yellow lesions spreading along leaf veins.

• Mosaic viruses – mottled yellow and green patterns on leaves. Spread by aphids.

Fix: Remove and destroy severely infected plants to prevent spread. Improve air circulation. Use row covers to exclude insect vectors. Plant resistant varieties when available.

Take a Close Look at Your Plants

Carefully inspect all your bean plants to spot early symptoms of any issues. Check both upper and lower leaf surfaces as well as the soil and roots. Identifying the specific problem is key before attempting to fix it.

Look for patterns like yellowing starting on older lower leaves versus newer top leaves, leaf veins remaining green, spots/lesions, leaf curling or stunting, etc. Also note any signs of pests.

Follow Good Growing Practices

Adhering to optimal growing conditions and care practices will help avoid many problems:

• Test soil pH and improve if needed
• Prepare soil well with compost and nutrients
• Use drip irrigation and mulch to maintain even moisture
• Allow proper spacing for air circulation
• Provide supports for climbing varieties
• Use row covers to protect from cold temperatures
• Monitor for pests like aphids which spread viruses
• Rotate bean crop locations each year

Remove Damaged Leaves

While working to correct the underlying issue, go ahead and pick off any badly yellowed or damaged leaves. This reduces stress on the plant and pests that may inhabit the leaves.

Don’t remove more than 20% of foliage at once, and avoid cutting off any still green healthy leaves. New leaves will generate as the plant recovers.

Apply Fertilizer or Compost

If nutrient deficiency is suspected, give your sickly looking beans some nourishment. Use an organic balanced fertilizer, compost tea, or simply top-dress around plants with compost.

Follow label instructions for proper dilution and application of any amendments. This can provide a quick boost while you work to improve growing conditions.

Adjust the Watering Schedule

If you suspect moisture stress is the culprit, modify your watering habits appropriately. Install drip irrigation or soaker hoses to provide a consistent supply of water.

Water early in the day to allow leaf surfaces to dry out in sunlight. Proper moisture will help leaves regain their green color.

Monitor Progress

After implementing corrective actions, keep an eye on your bean plants to spot improvement. Look for new growth emerging without yellowing. The older damaged leaves may not recover but new foliage indicates the plant is on the mend.

Make sure you addressed the underlying cause of the problem. Persistent yellowing may mean there are still issues with sun, water, temps, or disease requiring more intervention.

Be Patient

Don’t expect an overnight miracle. It can take a couple weeks for your green bean plants to fully recover once appropriate fixes are applied. The good news is beans are resilient and with proper care, they should be yielding tasty beans again before you know it!

Paying attention to your plants and rectifying any detrimental conditions will keep your bean patch vibrant and productive. A little yellow leaf trouble is certainly no reason to abandon hope!