Curling leaves usually mean your tomato plant is either too dry, too hot, or dealing with a pest or disease
Tomato leaf curl happens for five main reasons: underwatering, heat stress, spider mites, early blight, or herbicide drift. The leaves roll inward or upward as the plant tries to reduce water loss or respond to damage. You can identify which one by looking at the pattern of the curl, whether other symptoms are present, and the conditions around your plant over the last few days.
The good news is that most causes are fixable once you know what to look for. Some need when ready action — like removing infested leaves — while others just need a change in your watering or placement routine. A few, like certain diseases, mean removing the plant entirely to protect others nearby.
Key Takeaways
- Underwatering is the most common cause; soil should be moist two inches down, not soggy or bone-dry.
- Heat stress above 85°F causes upward leaf curl as a survival response, and shade cloth or afternoon shade can help.
- Spider mites create fine webbing and tiny yellow spots on the undersides of leaves, and need water spray or insecticidal soap.
- Early blight shows brown spots with concentric rings on lower leaves first, and requires removing affected leaves and improving air flow.
- Herbicide drift from nearby lawn or garden treatments can cause severe curling within hours and may kill the plant.
Underwatering and inconsistent soil moisture
Tomatoes need soil that stays consistently moist but not waterlogged. When the top two inches of soil are dry, the plant pulls water from its leaves to keep the roots alive, and the leaves curl inward as a defense. This is the most common cause of curling, especially in hot weather or in containers that dry out fast.
Check the soil by pushing your finger two inches into the ground near the base of the plant. If it feels dry, water deeply until water drains from the bottom of the pot or runs away from the base. Water in the early morning so the soil has time to absorb moisture before the heat of the day. Avoid watering in the evening, which can trap moisture around the stems and invite fungal disease.
Container tomatoes need water more often than garden tomatoes because pots heat up and dry out faster. In summer, a five-gallon pot may need water every day or every other day. Mulch around the base with two inches of wood chips or straw to slow evaporation and keep the soil temperature steady.
Heat stress above 85 degrees
When the air temperature stays above 85°F for several days, tomato plants curl their leaves upward to reduce the surface area exposed to the sun. This is a survival response, not a disease. The plant is trying to prevent water loss through the leaf surface. You will often see this curl happen in the afternoon and ease slightly in the evening or early morning.
Heat-stressed plants still need water, but curling leaves alone do not mean the plant is dying. However, if heat stress continues for weeks, the plant may drop flowers or fail to set fruit. Provide afternoon shade with a shade cloth (30 to 50 percent shade), position the plant where it gets morning sun but afternoon shade from a wall or tree, or move container plants to a shadier spot during the hottest part of the day.
Water more frequently during heat waves because the soil dries faster. Mulch heavily to keep roots cooler. Once temperatures drop below 85°F at night, the curling usually stops within a few days.
Spider mites and other pests
Spider mites are tiny arachnids that live on the undersides of leaves and suck out plant juices. Infested leaves curl, turn yellow or bronze, and develop a fine webbing if you look closely. The damage starts on the lower leaves and moves upward. Spider mites thrive in hot, dry conditions and spread quickly in summer.
Check the undersides of curled leaves with a magnifying glass or by holding a white paper under a leaf and tapping it — tiny moving dots are mites. If you find them, spray the entire plant, especially the undersides, with a strong stream of water from the hose every two to three days for two weeks. This knocks mites off and disrupts their life cycle. If water alone does not work, use insecticidal soap or neem oil, following the label directions and spraying in the early morning or late evening to avoid leaf burn.
Remove heavily infested leaves entirely and throw them in the trash, not the compost. Do not compost any diseased or pest-infested plant material.
Early blight and fungal disease
Early blight is a fungal disease that starts on the lowest leaves and works its way up. Infected leaves show brown spots with concentric rings (like a target), and the leaf may yellow and curl before dropping off. The disease spreads in warm, wet conditions, especially when water splashes from soil onto leaves.
Remove all affected leaves as soon as you see them, cutting at least six inches below the lowest spot. Throw the leaves in the trash. Do not compost them. Improve air flow around the plant by spacing it away from other plants, pruning lower branches, and staking it so air can move underneath. Water only at the soil level in the early morning, never overhead.
If the disease moves up the plant and covers more than a third of the foliage, the plant is unlikely to recover and may spread the disease to nearby tomatoes. Remove the entire plant and dispose of it. Do not compost it. Clean your pruning tools with a 10 percent bleach solution (one part bleach to nine parts water) before moving to another plant.
Herbicide drift from nearby treatments
Herbicide drift happens when someone sprays weed killer on a lawn or garden nearby, and the spray or vapors reach your tomato plant. Affected leaves curl severely, twist, become distorted, and may turn brown or purple within hours to a few days. The damage is often one-sided if the drift came from a particular direction.
There is no treatment for herbicide damage. If the damage is light and only affects a few leaves, remove those leaves and monitor the plant. If the damage is severe and covers most of the plant, the plant will likely die. Prevent drift by asking neighbors not to spray near your garden, or by creating a physical barrier like a fence or dense hedge between your tomatoes and treated areas.
If you use herbicides yourself, explore them on calm days, away from tomatoes and other vegetables, and follow all label directions. Drift can travel much farther than you expect, especially on windy days.
How to tell which problem you have
Start by looking at where the curl is worst. Underwatering and heat stress affect the whole plant fairly evenly. Spider mites and early blight start on the lower leaves. Herbicide damage is often one-sided or affects the newest growth.
Check the soil next. Stick your finger two inches down. If it is bone-dry, water is the problem. If it is moist, look at the undersides of the curled leaves for webbing or tiny moving dots (spider mites), or for brown spots with rings (early blight).
Look at the temperature and recent weather. If it has been above 85°F and sunny for days, heat stress is likely. If it has been warm and wet, fungal disease is more probable. If someone sprayed nearby in the last few days, consider herbicide drift.
| Cause | Leaf pattern | Other signs | When it happens |
|---|---|---|---|
| Underwatering | Inward curl, whole plant | Dry soil, wilting | Hot weather, containers |
| Heat stress | Upward curl, whole plant | Afternoon worse, eases at night | Above 85°F for days |
| Spider mites | Curl and yellow, lower leaves first | Fine webbing, tiny dots on undersides | Hot, dry conditions |
| Early blight | Curl and yellow, lower leaves first | Brown spots with rings, leaf drop | Warm, wet weather |
| Herbicide drift | Severe distortion, often one-sided | Purple or brown discoloration, rapid onset | After nearby spraying |
Frequently Asked Questions
Can a tomato plant recover from curled leaves?
Yes, if the cause is underwatering, heat stress, or spider mites. Once you fix the problem — water more, provide shade, or spray for mites — new growth will be normal and old leaves may uncurl slightly. Leaves damaged by early blight or herbicide will not recover, but removing them lets the plant focus energy on healthy growth.
Should I remove all the curled leaves?
Only if they show disease spots or heavy pest damage. Curled leaves from underwatering or heat stress are still feeding the plant, so leave them unless they are completely dead. Remove lower leaves affected by early blight, and remove any leaf with webbing or heavy mite damage.
Is it safe to eat tomatoes from a plant with curled leaves?
Yes, as long as the curling is from underwatering, heat, or spider mites. Tomatoes from plants with early blight are safe to eat if you remove the affected leaves and the fruit itself has no spots. Do not eat fruit from a plant damaged by herbicide drift.
How often should I water tomatoes to prevent curling?
Water when the top two inches of soil are dry, usually once a day in summer for container plants and two to three times a week for garden plants, depending on heat and rainfall. Consistent moisture is more important than a set schedule.
Can I use fungicide to stop early blight?
Fungicide can slow early blight but works best as prevention before the disease appears. Once spots are visible, removing affected leaves is more effective. If you want to use fungicide, choose one labeled for early blight on tomatoes and follow all directions. Copper fungicides and sulfur are common options for home gardeners.