Most plant diseases are far easier to prevent than to cure. They take hold when plants are stressed, crowded or wet, so a few good habits — airflow, spacing and watering at the roots — stop the vast majority before they start. Here are the ones you are most likely to meet and how to keep them away.
- Spots on leaves or stems
- Mildew white powdery coating
- Wilting despite moist soil
- Rot soft, mouldy growth
The common diseases
- Damping off. Seedlings collapse at the base in cold, wet, still conditions — see our guide to damping off.
- Powdery mildew. A white, dusty coating on leaves, common in late summer and on dry-rooted plants. Improve airflow and keep plants watered at the roots.
- Blight. Brown patches on tomato and potato leaves and fruit in warm, wet spells. Space plants well and remove affected growth fast.
- Rust. Orange or brown spots on leaf undersides. Remove affected leaves and avoid wetting foliage.
- Grey mould & rots. Fuzzy grey growth on soft, damaged or overcrowded plants. Tidy away dead material and improve airflow.
Why prevention beats cure
Disease loves damp, still, crowded conditions. Give plants room to breathe by spacing them properly, water at the base rather than over the leaves (and in the morning so foliage dries), and keep tools and pots clean. Healthy soil grows resilient plants that resist infection.
If disease strikes
Act quickly: remove and bin affected leaves or whole plants — do not put diseased material on the compost heap, where it can survive. Improve airflow, stop overhead watering, and give survivors space. Catching it early often saves the rest of the crop.
Build resilient plants
Strong plants rarely get sick. Feed the soil, space plants to the distance on the packet, rotate where you grow each crop family each year, and choose disease-resistant varieties where you can. Keep an eye out for pests too, as damage opens the door to disease.
Frequently asked questions
Can I cure a diseased plant?
Sometimes you can stop it spreading by removing affected parts, but prevention is far more reliable.
Can I compost diseased plants?
Best not to — many diseases survive composting. Bin or burn them instead.
How do I stop mildew?
Improve airflow, keep roots watered, and avoid wetting the leaves.
Do resistant varieties help?
Yes — they are bred to shrug off common diseases and are well worth choosing.
Keep plants healthy, then browse all seeds.
