Shown in photo: healthy zucchini plant
Yellow leaves on otherwise healthy squash plants can be disheartening to see. Here's what to know.
Squash can develop yellow leaves for several reasons, including overwatering or underwatering, nutrient deficiencies (like lack of nitrogen or magnesium), pests (such as squash bugs or aphids), fungal diseases (like powdery mildew or root rot), poor drainage, or natural aging of older leaves as the plant matures.
Checking soil moisture, feeding appropriately, inspecting for pests, and improving air circulation usually help pinpoint and fix the issue.
Here's an article with more information.
Checking soil moisture, feeding appropriately, inspecting for pests, and improving air circulation usually help pinpoint and fix the issue.
- Check soil moisture — make sure you’re not overwatering or underwatering. Water deeply when the top inch of soil feels dry.
- Feed the plant — apply a balanced vegetable fertilizer every 2-4 weeks during the growing season with a balanced fertilized like NPK 5-10-10 or compost tea.
- Inspect for pests — look under leaves for aphids, squash bugs, or spider mites; remove them by hand or spray with insecticidal soap such as Neem Oil. For squash bugs try food-grade diatomaceous earth powder.
- Improve airflow — space plants 2-3 feet apart in rows 3-5 feet apart and remove any crowded, diseased leaves to reduce fungal problems.
- Prune older yellowing leaves — if they’re naturally aging, prune them to redirect energy to healthy growth.
Here's an article with more information.