Cucumber leaves turn yellow primarily due to factors such as improper watering, nutrient deficiencies, pests, diseases, and environmental stresses.
Common Causes for Yellowing Cucumber Leaves
- Watering Issues: Both underwatering and overwatering can cause yellow leaves. Underwatering leads to dehydration and leaf yellowing, while overwatering causes root suffocation, root rot, and poor nutrient uptake, resulting in yellowing leaves.
- Nutrient Deficiency: Lack of nitrogen is a key cause since nitrogen is vital for chlorophyll production. Magnesium deficiency can also cause yellowing between leaf veins (interveinal chlorosis). Balanced fertilization can prevent this.
- Environmental Stress: Insufficient sunlight leads to poor photosynthesis and yellow leaves. Excessive sunlight and heat can cause leaf burn, dehydration, and yellowing. Temperature extremes also affect leaf color.
- Pests: Aphids, spider mites, whiteflies, cucumber beetles, and thrips feed on cucumber leaves, causing yellowing and transmitting viruses that worsen the condition.
- Diseases: Conditions like downy mildew can cause yellow spots and leaf drop.
What to Do
- Check soil moisture and adjust watering to keep soil consistently moist but not soggy.
- Ensure cucumber plants get 6-8 hours of sunlight daily.
- Apply balanced fertilizers rich in nitrogen, potassium, phosphorus, and magnesium as needed.
- Inspect and treat for pests promptly.
- Protect plants from temperature extremes and excessive heat.
Addressing these areas should help restore the healthy green foliage of cucumber plants and prevent further yellowing.
