Why Are My Tomato Leaves Curling, Yellowing or Turning Brown?
Changes in tomato leaves are often the first indication that a plant is under stress. Leaves may curl, turn yellow, develop brown edges or become marked with spots.
These symptoms do not always mean the plant has a disease. Heat, watering, root disturbance, nutrition, natural ageing and physical damage can all alter the appearance of tomato foliage.
The position of the affected leaves, the pattern of damage and the speed at which it develops provide important clues. Before treating the plant, examine the whole plant and consider its recent growing conditions.
Begin With the Pattern of Damage
Look at where the symptoms first appeared.
Ask:
Are the oldest lower leaves affected first?
Is the newest growth distorted?
Is the damage limited to one side of the plant?
Are several plants showing the same symptoms?
Are there spots, rings, holes, trails or webbing?
Is the plant still growing normally?
Did the symptoms follow extreme heat, cold, heavy rain or drought?
Has fertiliser recently been applied?
Is the soil dry, consistently moist or waterlogged?
Are insects visible on the undersides of leaves?
One damaged leaf may have been shaded, bent or physically injured. A pattern spreading through the plant requires closer investigation.
Why Tomato Leaves Curl
Tomato leaves may roll upwards, curl downwards or become twisted and distorted. These patterns can have different causes.
Physiological Leaf Roll
Physiological leaf roll is a common response to environmental stress. The edges of the leaves roll upwards and inwards, sometimes forming a tube-like shape.
It often begins on the lower leaves while the foliage remains green and reasonably firm.
Possible triggers include:
High temperatures
Strong sunlight
Dry soil
Irregular watering
Heavy pruning
Root damage
Transplant shock
Strong winds
Rapid changes in weather
Physiological leaf roll is not infectious. It does not spread between plants, although several tomatoes may show it after experiencing the same conditions.
Some varieties are naturally more inclined to roll their leaves than others.
What to Do About Physiological Leaf Roll
Check soil moisture below the surface and correct any severe dryness or waterlogging. Water deeply and consistently rather than applying frequent small amounts.
Avoid removing additional foliage. A plant experiencing heat and water stress needs its healthy leaves for photosynthesis and fruit protection.
Existing leaves may remain curled even after conditions improve. The appearance of healthy new growth is a better sign of recovery than whether older leaves flatten again.
Downward-Curling Leaves
Leaves curling downwards can be associated with:
Excessive nitrogen
Overwatering
Root stress
Chemical injury
Sap-feeding pests
Certain diseases
Natural leaf shape
If the plant is unusually dark green, soft and leafy but has few flowers, excessive nitrogen may be contributing.
Check the growing tips and leaf undersides for insects. Also consider whether the plant has recently been exposed to a spray, contaminated compost or drifting weedkiller.
Twisted or Narrow New Leaves
Severely twisted, cupped or unusually narrow new growth requires careful inspection.
Possible causes include:
Aphids
Mites
Herbicide exposure
Viral infection
Severe temperature stress
Damage to the growing tip
Herbicide injury can cause tightly curled, strap-like or distorted foliage. Damage may affect several plants along the same boundary or on the side exposed to spray drift.
Herbicide residues can also enter a garden through contaminated manure, compost, straw or grass clippings. Consider all recently introduced materials if several unrelated broad-leaved plants show similar distortion.
Why Lower Tomato Leaves Turn Yellow
A small number of lower leaves may turn yellow naturally as the plant matures. Older foliage eventually becomes shaded and less efficient.
Remove a lower leaf when it is mostly yellow, touching the soil or no longer contributing to the plant.
More extensive yellowing may be caused by:
Excessive watering
Inadequate watering
Poor drainage
Root restriction
Nutrient stress
Dense shade
Cold soil
Root damage
Disease
Check whether the yellow leaves also contain spots or lesions. Uniform yellowing suggests a different problem from yellowing accompanied by distinct brown or black marks.
Yellowing Caused by Overwatering
Tomato roots need both moisture and oxygen. When soil remains saturated, air is displaced and roots cannot function normally.
Possible signs include:
General yellowing
Wilting despite wet soil
Soft growth
Slow development
Leaf drop
A sour smell from container compost
Dark or decaying roots
Do not add more water to a wilting plant without checking the soil first.
Reduce unnecessary watering and correct any drainage problem. A container should have clear drainage holes and should not remain in stagnant water.
Yellowing Caused by Drought
Prolonged dry conditions can also cause lower leaves to yellow and die.
Other signs may include:
Wilting during the day
Dry soil below the surface
Flower drop
Small fruit
Blossom end rot
Dry, curling leaf edges
Water slowly and deeply. Avoid flooding severely dry soil all at once if the water simply runs off; apply it in stages so it can soak into the root zone.
Mulching can reduce rapid moisture loss and help maintain more stable conditions.
Yellow Leaves and Nutrient Problems
Nutrient-related symptoms can be difficult to diagnose from leaf colour alone. Different shortages can produce similar patterns, and the nutrient may be present in the soil but unavailable to damaged or waterlogged roots.
Uniformly Pale or Yellow Plants
A generally pale plant with slow growth may lack available nitrogen, particularly when growing in an exhausted container or poor soil.
However, similar symptoms can be caused by:
Waterlogged roots
Cold soil
Root disease
Severe root restriction
Inadequate light
Unsuitable soil pH
Check the growing conditions before applying fertiliser.
Yellowing Between Green Veins
When the areas between the veins turn yellow while the veins remain greener, the plant may be having difficulty obtaining or using a nutrient.
The position of the affected leaves can provide clues, but visible symptoms are not always conclusive. Possible causes include:
A genuine nutrient deficiency
Unsuitable soil pH
Excess of another nutrient
Root damage
Waterlogging
Salt build-up
Cold conditions reducing root activity
Do not repeatedly add different nutrients in the hope that one will work. A soil or compost test is more reliable where the problem persists.
Yellow Leaf Edges
Yellowing around the edges may be associated with:
Water stress
Root damage
Excess fertiliser
Salt accumulation
Nutrient imbalance
Heat stress
Review recent feeding and watering. Container-grown plants are particularly vulnerable to accumulated fertiliser salts.
Can Epsom Salt Correct Yellow Tomato Leaves?
Epsom salt contains magnesium sulphate. It may help only when a genuine magnesium deficiency is present.
Routine application is not a general treatment for yellow leaves. Excess magnesium can interfere with the uptake of other nutrients, including calcium.
Because yellowing can result from many different causes, identify the likely problem before adding magnesium or any other nutrient.
Why Tomato Leaves Turn Brown
Brown leaf tissue is dead and will not become green again. The aim is to identify and correct the cause so that healthy foliage is protected.
Brown, Dry Leaf Edges
Dry, crisp edges may be caused by:
Drought
Hot winds
Excess fertiliser
Salt accumulation
Root damage
Heat reflected from walls or paving
Leaves touching a hot surface
Check whether the soil has dried deeply and whether the plant has recently been fed.
If fertiliser has been overapplied to a container, stop feeding. Where drainage is good, watering thoroughly may help move excess soluble salts through the compost.
Brown Patches After Strong Sun
Indoor-raised tomato plants can develop pale, bleached or brown patches when moved directly into strong sunlight.
This is sunscorch. It commonly appears as dry, papery damage on the most exposed leaves.
Affected tissue will not recover, but new leaves should develop normally if the plant is gradually hardened off and protected from further sudden exposure.
Brown Areas After Cold Weather
Cold temperatures can darken, brown or kill tomato leaves. The growing tip may also be damaged.
Wait until the full extent of the injury becomes clear before removing affected growth. If the main stem and roots remain healthy, the plant may recover from minor cold damage.
Tomatoes exposed to frost are often too badly damaged to recover reliably.
Brown Areas Caused by Wind
Strong wind can tear leaves, dry their edges or cause them to rub against stakes and supports.
Wind damage is often concentrated on the exposed side of the plant. The damaged areas usually remain dry and do not continue expanding after conditions improve.
Provide better support or shelter without enclosing the plant so tightly that airflow is lost.
Brown or Black Spots on Tomato Leaves
Distinct spots require closer inspection, particularly when they increase in number or move upwards through the plant.
Small Spots on Lower Leaves
Small brown or black spots surrounded by yellowing may indicate a fungal or bacterial leaf infection.
Remove badly affected lower leaves and place them away from healthy plants. Avoid splashing water from the soil onto the remaining foliage.
Spots With Concentric Rings
Brown spots containing darker circular rings are commonly associated with early blight.
The disease often begins on older, lower leaves and can progress upwards. Dark lesions may also appear on stems and fruit.
Numerous Tiny Dark Spots
Many small spots can be associated with Septoria leaf spot or certain bacterial diseases.
The precise size, colour, border and distribution of the spots help distinguish between them. Because several infections can look similar, avoid relying on one photograph or symptom alone.
Rapidly Expanding Dark Patches
Large, dark, water-soaked or rapidly expanding lesions can indicate a serious infection, including late blight.
Wet or humid weather can allow symptoms to develop quickly. Inspect stems and nearby plants and act promptly when an infectious disease is suspected.
White, Grey or Fuzzy Growth
Visible fungal growth on leaves, particularly during humid conditions, suggests an infection rather than simple water stress.
Avoid handling healthy plants after touching affected wet foliage. Clean tools before using them elsewhere.
When Yellowing and Spots Occur Together
Yellowing around a dead spot can be the plant’s response to infection or damaged tissue.
Consider disease more likely when:
The number of spots is increasing
Symptoms are moving from lower to upper leaves
Similar marks appear on stems or fruit
Several plants become affected over time
Conditions have been wet or humid
The affected areas continue expanding
Environmental damage is more likely when symptoms appeared immediately after a heatwave, cold night, spray application, hailstorm or other identifiable event and do not continue spreading.
Could Pests Be Causing the Leaf Damage?
Sap-feeding and leaf-feeding pests can cause curling, yellowing, browning or distortion.
Aphids
Aphids gather on tender shoots and the undersides of leaves. Their feeding can cause new growth to curl or distort.
They may also produce sticky honeydew, which can later become covered by dark sooty mould.
Whiteflies
Adult whiteflies may fly up when the plant is disturbed. Their young stages feed on the undersides of leaves and can cause yellowing and general weakness.
Sticky honeydew may also be present.
Spider Mites
Spider mites produce fine pale speckling that can eventually make leaves look bronze, dry or brown.
Fine webbing may be visible between leaves and stems. They are particularly troublesome in hot, dry conditions.
Thrips
Thrips can create silvery, scarred or distorted foliage. Tiny dark specks of waste may be visible near the feeding damage.
Leaf Miners
Leaf-miner larvae create pale, winding trails within the leaf. The damage is usually easy to distinguish from nutrient problems or fungal spots.
Leaf-Eating Pests
Caterpillars, beetles, slugs, snails and grasshoppers remove parts of the leaf rather than simply changing its colour.
Look for holes, ragged edges, droppings, eggs or the pests themselves.
Could a Virus Cause Curling and Yellowing?
Some viral diseases cause combinations of:
Leaf curl
Yellowing
Mottled or mosaic patterns
Stunted growth
Narrow or distorted leaves
Poor flower and fruit production
Viral symptoms can resemble herbicide injury, nutrient stress or pest damage. Some viruses are spread by sap-feeding insects, while others can be carried on plant material or through physical contact.
A severely stunted and distorted plant that fails to produce normal new growth may need to be removed, particularly if nearby plants remain healthy and an infectious problem is suspected.
There is no treatment that removes a virus from an infected tomato plant.
Should Damaged Tomato Leaves Be Removed?
Remove leaves that are:
Clearly diseased
Mostly yellow or dead
Touching the soil
Badly damaged
Restricting essential airflow
Do not remove every imperfect leaf. Small marks, minor holes and limited edge damage do not prevent the rest of a leaf from photosynthesising.
Excessive leaf removal can:
Reduce the plant’s ability to produce energy
Slow fruit development
Expose tomatoes to sunscald
Increase heat stress
Weaken the plant
Reduce the harvest
Where possible, remove only two or three leaves at a time. Use clean tools for thick leaf stems and avoid tearing the main stem.
Removing Lower Tomato Leaves Safely
Removing selected lower leaves can improve airflow and reduce contact between foliage and the soil.
Prioritise leaves that are:
Resting on the ground
Regularly splashed during watering
Yellowing naturally
Damaged
Showing clear disease symptoms
As the lowest trusses develop, a limited number of leaves beneath them may be removed. Healthy foliage higher on the plant should remain unless there is a clear reason to take it off.
Avoid severe pruning during very hot or intensely sunny weather. Fruit that developed in shade can scorch when suddenly exposed.
Should a Leaf Spray Be Used?
Do not apply a spray until the cause has been identified.
A fungicide will not correct:
Heat stress
Watering problems
Nutrient imbalance
Root damage
Herbicide injury
Natural leaf ageing
An insecticidal treatment will not help when no pest is present.
Some sprays can damage leaves when applied in strong sunlight, high temperatures or at an unsuitable concentration. A stressed plant may be particularly vulnerable.
Begin by correcting the growing conditions and use a treatment only when there is a clearly identified problem for which it is appropriate.
A Quick Leaf-Symptom Checklist
Lower leaves curl upwards but remain green
Likely causes include heat, drought, irregular watering, heavy pruning or root disturbance.
New leaves are tightly curled or twisted
Check for aphids, mites, herbicide injury, damage to the growing point or viral symptoms.
A few old lower leaves are yellow
This may be natural ageing, particularly if the rest of the plant remains healthy.
Many lower leaves are yellow
Check watering, drainage, roots, light, nutrition and the presence of spots.
The whole plant is pale
Check root health, available nitrogen, light levels, soil temperature and container size.
Leaf edges are dry and brown
Check for drought, hot wind, excess fertiliser, salt build-up or root damage.
Leaves have pale, papery patches
Consider sunscorch, especially after plants have been moved outdoors.
Leaves have brown spots with rings
Investigate a possible fungal disease such as early blight.
Leaves contain many small dark spots
Investigate leaf spot or a bacterial infection.
Leaves have rapidly spreading dark patches
Treat the problem as potentially serious and investigate blight or another aggressive infection promptly.
Leaves have pale speckles and fine webbing
Check for spider mites.
Leaves are sticky
Check for aphids, whiteflies or another honeydew-producing pest.
Respond to the Cause, Not Just the Leaf
Damaged leaves cannot repair themselves, so improvement is usually seen in the new growth.
Begin with the basic conditions:
Check moisture below the soil surface.
Confirm that drainage is working.
Review recent temperatures and sunlight.
Inspect leaves closely for pests.
Look for spreading spots or stem lesions.
Consider recent feeding or spray exposure.
Compare the plant with nearby tomatoes.
Remove only foliage that genuinely needs to go.
One or two damaged leaves rarely threaten an established tomato plant. A problem becomes more concerning when it spreads, affects new growth, causes stems to develop lesions or prevents the plant from flowering and fruiting.
Careful observation and measured action will usually reveal whether the plant needs a change in its growing conditions, protection from a pest or a more urgent response to disease.
For complete advice on growing healthy tomato plants from sowing through to harvest, return to How to Grow Tomatoes: Complete Guide.
