Why Are My Tomato Leaves Curling?
Tomato leaves that curl can look alarming, but the cause is often temporary stress rather than disease. Heat, uneven watering and sudden changes in growing conditions are common in British gardens. Check the pattern carefully before acting, because distorted new growth or contaminated compost needs a different response.
Start by checking where and how the curling appears. Leaves that roll upwards on a warm, bright afternoon, particularly on lower parts of an otherwise healthy plant, usually reflect heat or moisture stress. Feel the compost 5 cm below the surface rather than judging it by colour alone. If it is dry, water slowly around the root zone until moisture reaches the full depth of the pot or bed. If it is sodden, stop watering and improve drainage. In a greenhouse or polytunnel, open doors, vents and windows early on sunny days. Give plants some shade with horticultural fleece during exceptional heat, but remove it when temperatures settle so light levels remain good.
Keep watering regular rather than giving tomatoes frequent small splashes. In pots, grow bags and greenhouse borders, water at the base in the morning whenever the compost is beginning to dry, using enough to moisten the root ball evenly. Check containers daily in warm June, July and August weather, as wind can dry them quickly. Mulch outdoor plants with 3 to 5 cm of garden compost, leaf mould or clean grass clippings, leaving a small clear gap around stems. This slows evaporation and reduces temperature swings in the soil. Make sure every pot has clear drainage holes and stands where excess water can escape rather than collecting in a tray.
Examine new leaves closely for clues that the problem is more serious. Healthy stress curl leaves stay green and flexible, while virus or pest damage may bring mottling, yellow patches, stunting, thickened veins or badly twisted young shoots. Look beneath leaves for whitefly, aphids and red spider mite, especially on greenhouse tomatoes. Rinse small aphid colonies off with a firm spray of plain water and improve ventilation to discourage pests. Remove only badly damaged leaves with clean secateurs; do not strip plants bare. If symptoms spread rapidly between plants, isolate the worst one and avoid handling healthy plants immediately afterwards, as sap can transfer some infections.
Consider whether weedkiller contamination is possible if growth is unusually narrow, twisted or fern-like. Some persistent weedkiller residues can pass through manure, green waste or grass clippings and affect tomatoes, beans and potatoes even after composting. This remains a recognised risk for UK gardeners using materials from uncertain sources. Stop using the suspected mulch, manure or compost and do not add it to your compost heap or bin. Plant a few broad beans in a small sample as a simple indicator: distorted young leaves suggest a problem. Contact the supplier if relevant, and grow future crops in fresh peat-free multipurpose compost or clean soil while the area recovers.
Avoid making leaf curl worse through overfeeding. Tomatoes need regular nutrition once fruits are setting, but fertiliser cannot correct roots that are alternately parched and waterlogged. Feed only according to the product label, after watering if the compost is dry. Do not use fresh manure around tomato roots, as it can be too rich and uneven in strength. In greenhouse borders, renew the surface with garden compost each spring and rotate crops where practical. If plants are rootbound, move young specimens into larger containers before flowering. Mature plants in small pots may continue to curl in hot spells, so prioritise steady water, airflow and a mulch rather than disturbing established roots.
Most weather-related curl does not need a dramatic cure and may not fully uncurl, but new leaves should emerge normally once conditions improve. Keep a simple note of watering, temperature and any compost or mulch added, which makes recurring problems easier to trace. In cooler northern areas and Scotland, avoid closing a greenhouse too tightly after a sunny day because nights can still become cold. In milder southern gardens, midday shade and generous ventilation are often more important. Dispose of plants only when growth remains severely distorted, mottled or unproductive despite stable care. Otherwise, continue harvesting and monitor the newest leaves rather than judging the whole plant by older foliage.
Frequently asked questions
Can curled tomato leaves recover?
Leaves curled by heat or uneven watering may remain curled, but the plant can recover perfectly well if new growth is normal. Stabilise watering, improve ventilation and avoid extra feeding until the root zone is evenly moist. Watch the youngest leaves for one to two weeks before deciding whether there is a more persistent problem.
Should I cut curled leaves off tomatoes?
Usually no. Green curled leaves still make energy for the plant, so remove them only if they are badly damaged, diseased or blocking airflow near the soil. Use clean secateurs and take a few at a time. Removing too much foliage suddenly can expose fruit to scorching and stress the plant further.
Can contaminated manure cause tomato leaf curl?
Yes. Residues from persistent weedkiller can sometimes survive in manure, composted green waste or grass clippings and cause severe twisting of new tomato leaves. Stop using suspected material and do not compost it again. Fresh peat-free compost and clean soil are the safest options for replacement plants.
General guidance for UK home gardens and allotments. Conditions vary by region, soil and season; the RHS or a local garden centre can give site-specific advice. Page updated 19 Sep 2026.