Why are my tomato leaves curling?

Last updated: October 2026

Most often, tomato leaves curl because of physiological leaf roll, a stress response to heat, drought, wet soil, heavy pruning or root damage^1,2. Lower leaves cup upward, then roll inward toward the midrib, but stay green, and yield is barely affected¹. Curling on new growth with yellowing, twisting or stunting points instead to herbicide drift, tomato yellow leaf curl virus or mites^5,6,8.

How do you tell what is making tomato leaves curl?

Start with where the curl is and what color the leaves are. Curling or rolling of tomato (Solanum lycopersicum) leaves can come from environmental stress, virus infection or herbicide damage¹. Heat or drought curl usually shows first on the lower leaves without yellowing between the veins, while tomato yellow leaf curl virus yellows the margins and the tissue between the veins of young leaves first⁶. Curling of new leaves can also come from heavy aphid feeding or other viruses⁶.

In North America, tomato leaf roll shows up most as spring weather shifts to summer, and searches peak in June; 2,4-D drift injury also clusters in May and June. In the Southern Hemisphere, the same window falls around November to January.

Why are my tomato leaves curling up?

Upward curling of otherwise healthy, green leaves is the classic sign of physiological leaf roll¹. It starts in the lower leaves with an upward cupping of the leaflets, which then roll lengthwise toward the midvein; the leaves thicken and turn leathery but keep a normal green color, and over time the whole plant can be affected¹. The edges of many, but not all, leaves roll upward and inward, sometimes until the sides touch or overlap².

Water relations are the suspected cause in many cases³. When water uptake drops or demand rises, the plant rolls its leaves, which reduces the leaf area exposed to strong sunlight³. Triggers include excess moisture and nitrogen, too little phosphorus, heat, drought, severe pruning, root damage from tilling or hoeing, early planting and transplant shock¹. Severe pruning while the soil is dry, or wet soil combined with hot weather, has also been associated with the problem².

Variety matters. High-yielding and indeterminate (vining) tomatoes appear more sensitive than other types², and vining varieties show leaf roll more often than bush (determinate) varieties¹. The disorder has minimal impact on fruit production and plant growth¹, and it does not affect fruit yield or quality².

Why are tomato leaves curling inward?

Leaves that roll inward along their length, with the margins moving toward the midrib, are showing the second stage of physiological leaf roll¹. In tomatoes, the roll starts at the margins, which turn up and then roll inward, most commonly on the lower leaves³. The roll can be brief or can last for the rest of the season².

To reduce it, keep soil moisture consistent with mulch, avoid excess nitrogen, apply phosphorus according to a soil test, harden off seedlings before planting, transplant once the weather has warmed, and avoid heavy pruning and root damage¹. A well-timed irrigation schedule that prevents both overly dry and overly wet soil, protection from temperatures above 95°F, and planting determinate varieties also help². Siting tomatoes where they get shade in the late afternoon, the hottest time of day, is another recommended practice¹.

Can herbicide drift make tomato leaves curl?

Yes. Tomatoes are very sensitive to 2,4-D, and drift injury usually occurs in May and June; the youngest leaves become twisted, curled and strappy and stay small⁵. Growth regulator herbicides mimic the plant hormone auxin, and similar symptoms come from dicamba, triclopyr, picloram, clopyralid, aminopyralid and related products⁴. Typical 2,4-D symptoms on tomato include downward rolling of leaves and twisted growth, stems that turn white and split, and deformed fruit¹.

Exposure comes from drift droplets, vapors after application or a contaminated sprayer⁴. Ester formulations tend to be more volatile than amine, choline or salt forms and can vaporize during or shortly after application⁴. Residues of some of these herbicides can persist in hay or in livestock manure and urine, so manure from livestock fed treated hay or pasture can carry them into a garden⁴.

Suspect herbicide injury when more than one type of plant is affected, when symptoms appear on only one portion of a plant or planting, and when nutrient problems, insects and diseases have been ruled out⁵. Exposed plants cannot be cured; plants that survive may grow out of the injury, but production can still be affected, and fruit from plants damaged by herbicides not labeled for tomatoes should not be sold or eaten⁴. Even a small amount of residual herbicide can injure tomatoes, so keep a dedicated sprayer for herbicides⁴.

Which viruses make tomato leaves curl?

Tomato yellow leaf curl virus (TYLCV), a threat to tomatoes in the southern United States, Mexico and the Caribbean, curls leaves upward and downward⁶. Infected plants are stunted, grow abnormally upright and look bushy, and their leaves are small, strongly crumpled, curl upward and turn yellow at the edges and between the veins⁷. Flowers commonly drop before fruit set, and losses can reach 100% in heavily infected fields⁷. Symptoms can take up to three weeks to appear after infection⁶.

TYLCV is spread by the sweetpotato whitefly, Bemisia tabaci, and not by other whitefly species; it is not spread by touch⁷. The common greenhouse whitefly does not transmit it⁷. Because symptoms overlap with other viruses, symptoms alone cannot confirm TYLCV, and a plant clinic or extension specialist should confirm the diagnosis^7,6. Planting resistant varieties is an economical way to manage it⁶.

Other viruses curl leaves too. Tomato mosaic virus causes leaf rolling with mottled leaves, small leaflets and internal browning of the fruit¹. Cucumber mosaic virus, spread by aphids, causes leaf and stem distortion that can be mistaken for 2,4-D damage⁴. There is no treatment for virus-infected plants; remove and destroy them, control weeds that host the viruses, and disinfect pruners used on diseased plants¹.

Can insects and mites make tomato leaves curl?

Broad mites (Polyphagotarsonemus latus) cause curling that is easy to misdiagnose⁸. Tomato is one of their host crops, and their toxic saliva produces twisted, hardened and distorted growth at the tips of the plant; leaves turn downward and become coppery or purplish, and internodes shorten⁸. The mites gather on the newest leaves and small fruit and are hard to see without a hand lens of 10x or stronger, and their injury is easy to confuse with herbicide injury, boron deficiency or physiological disorders⁸. Insecticidal oils or soaps are usually as effective as labeled miticides against them⁸; follow the product label.

Heavy aphid feeding can also curl new tomato leaves⁶. When a virus is the cause of curled, distorted leaves, its insect vectors, aphids for cucumber mosaic virus and whiteflies for TYLCV, will usually be present and easy to see in the planting⁴. Check leaf undersides for these insects before blaming herbicide drift⁴.