Tomato Fruit Problems: Cracking, Splitting, Sunscald and Uneven Ripening
Tomatoes do not need to look perfect to be usable. Their skins may split, shoulders may remain green, exposed areas may become pale or the fruit may ripen unevenly.
Many of these problems are physiological disorders caused by weather, moisture, temperature or the way the fruit develops. They are not infectious and cannot spread from one tomato to another.
Correct identification is important because damaged fruit may later develop mould or decay even when the original problem was not a disease.
Start by Examining the Damage
Look at where and how the problem appears.
Ask:
Is the damage at the stalk end, blossom end or side of the fruit?
Is the skin split or unbroken?
Is the affected tissue firm, dry, soft or water-soaked?
Did the problem appear after rain or heavy watering?
Is the fruit exposed to direct sunlight?
Are several fruits affected in the same way?
Are there related symptoms on the leaves or stems?
Is mould or liquid developing inside the damaged area?
Is the variety known for thin skin, large fruit or green shoulders?
A firm, dry blemish is different from a soft lesion that continues spreading. The second may indicate secondary decay or an infectious disease.
Why Tomatoes Crack or Split
Tomato cracking usually occurs when the inside of the fruit expands faster than its skin can stretch.
This commonly follows a rapid increase in water availability. After a dry period, heavy rain or generous watering can cause the fruit to absorb water quickly and swell.
Contributing factors include:
Irregular watering
Heavy rain after dry weather
Allowing containers to dry out
Rapid fruit growth
Overripe fruit
High temperatures
Loss of protective foliage
Variety susceptibility
Large differences between daytime and night-time conditions
Cracking is a physiological problem. It is not contagious.
Radial Cracking
Radial cracks begin near the stalk and extend down the side of the tomato.
These splits may be deep and can expose the inner flesh. This makes the fruit vulnerable to:
Mould
Bacterial decay
Insects
Slugs and snails
Further splitting
Radial cracking is often associated with a sudden increase in water uptake as fruit approaches ripeness.
Concentric Cracking
Concentric cracks form in circles around the stalk end of the tomato.
They may remain shallow and dry or become deep enough to expose the flesh. Large-fruited varieties commonly develop this type of cracking.
Fruit with shallow, healed concentric cracks can often remain usable. Inspect it carefully because moisture and pests can enter deeper cracks.
Fine Surface Cracks or Rain Checking
Some tomatoes develop many fine, shallow lines across the skin. This is sometimes called rain checking.
The cracks may create a rough or netted appearance without extending deeply into the fruit.
Possible causes include:
Rain or high humidity
Water remaining on the skin
Rapid changes in moisture
Variety susceptibility
Fruit remaining on the plant after it is fully ripe
The fruit is often usable if the skin remains intact enough to prevent decay.
How to Prevent Tomato Cracking
It may be impossible to prevent every split during prolonged rain, but the risk can be reduced.
Maintain Consistent Soil Moisture
Water deeply and regularly enough to prevent the root zone from repeatedly becoming severely dry.
Check the soil approximately 5–8 centimetres below the surface. Water when it is dry at that depth rather than following a fixed schedule regardless of conditions.
Apply Mulch
Organic mulch helps reduce evaporation and slows rapid changes in soil moisture.
Apply it over moist soil, keeping thick material slightly away from the main stem.
Use Adequate Containers
Small containers dry quickly and make moisture difficult to regulate.
Choose a container appropriate for the mature size of the plant. Check container tomatoes frequently during hot or windy weather.
Harvest Ripe Fruit Promptly
Tomatoes become more vulnerable to cracking as they ripen.
Harvest fruit that has begun changing colour when heavy rain is expected. Tomatoes that have reached the mature green or colour-break stage can continue ripening indoors.
Retain Healthy Foliage
Leaves help regulate the plant’s water use and protect fruit from intense weather.
Removing too many leaves can expose tomatoes to rapid heating, cooling and direct rain.
Choose Less Susceptible Varieties
Some varieties have more flexible or resilient skins than others. If cracking occurs every year despite good moisture management, trialling a more resistant variety may help.
Are Cracked Tomatoes Safe to Eat?
A freshly cracked tomato may still be usable if:
The split is clean
The flesh remains firm
There is no mould
There is no unpleasant smell
Insects have not entered
Decay has not spread inside
Wash the tomato and cut away the damaged section generously. Use it promptly rather than storing it.
Discard fruit that is:
Soft or leaking
Mouldy
Sour or unpleasant-smelling
Extensively rotten
Contaminated by animal waste
Filled with insects or larvae
When in doubt, do not eat it.
What Is Sunscald?
Sunscald occurs when tomato fruit is exposed to intense sunlight and heat.
It usually appears as a pale yellow, white or bleached patch on the side receiving the strongest sun. The affected area may later become flat, dry, papery or sunken.
Sunscald is not an infection. However, the damaged tissue can later become colonised by moulds and bacteria.
Why Tomatoes Develop Sunscald
Fruit is most likely to scorch when it loses the leaf cover that previously protected it.
Common causes include:
Excessive pruning
Removing too many lower or surrounding leaves
Leaf loss caused by disease
Pest damage
Broken branches
Plants falling away from their supports
Sudden movement of foliage
Extreme heat and intense sunlight
Green or partly ripe tomatoes are particularly vulnerable.
Fruit that has developed in shade is not adapted to sudden exposure. Removing several leaves during hot weather can cause damage very quickly.
How to Prevent Sunscald
Retain a Healthy Leaf Canopy
Healthy leaves shade fruit and help regulate its temperature.
Remove only foliage that is:
Diseased
Mostly dead
Touching the soil
Badly damaged
Preventing essential airflow
Do not strip leaves simply to expose tomatoes to sunlight. Direct sun is not required for the fruit to ripen.
Prune Gradually
Where leaf removal is necessary, take only two or three leaves at a time. This allows the plant and fruit to adjust.
Avoid severe pruning immediately before or during extreme heat.
Support Plants Securely
Tie stems and fruit-laden branches before they collapse or turn suddenly towards the sun.
Check ties regularly and add support as the crop becomes heavier.
Provide Temporary Shade
During exceptional heat, light shade may protect exposed plants and fruit.
The aim is to reduce the most intense sunlight without placing the whole plant in deep shade.
Control Leaf-Damaging Problems
Disease and pest damage can remove the canopy even when the plant has not been pruned.
Inspect plants regularly and respond before extensive defoliation occurs.
Can Sunscalded Tomatoes Be Used?
A lightly affected tomato may still be usable if the damaged area remains dry and the rest of the fruit is firm.
Cut away the affected tissue generously and inspect the inside.
Discard fruit if the damaged area has become:
Soft
Mouldy
Wet
Leaking
Foul-smelling
Extensively decayed
Sunscald itself is not contagious, but the damaged tissue is vulnerable to secondary infection.
Why Tomatoes Ripen Unevenly
Uneven ripening occurs when part of a tomato develops its normal ripe colour while another part remains green, yellow, pale or firm.
It can appear as:
Green or yellow shoulders
A blotchy surface
Hard pale areas
Uneven red colouring
Internal white or hard tissue
One side ripening before the other
Possible causes include:
High temperatures
Intense sunlight
Nutrient imbalance
Root stress
Inadequate healthy foliage
Variety characteristics
Poor plant health
Certain pests
Some diseases
The pattern and the condition of the rest of the plant help identify the likely cause.
Green Shoulders
Green shoulders occur when the area around the stalk remains green or hard while the lower part of the fruit ripens.
The green area may eventually soften and colour, or it may remain firm and less pleasant to eat.
Contributing factors include:
Variety genetics
High temperatures
Strong sunlight
Incomplete chlorophyll breakdown
Nutrient imbalance
Loss of protective foliage
Some older and heirloom varieties naturally retain green shoulders more readily than modern varieties bred for uniform ripening.
Yellow Shoulders and Blotchy Ripening
Yellow shoulder disorder causes areas near the top or side of the tomato to remain yellow, pale or firm.
The outside may look partly ripe while the flesh beneath the affected area remains white or hard.
Factors associated with this problem include:
High fruit temperatures
Nutrient imbalance
Compacted soil
Restricted roots
Poor soil conditions
Inadequate leaf cover
Variety susceptibility
Avoid applying one nutrient based only on the fruit’s appearance. Soil testing is more reliable where the problem occurs repeatedly.
How Heat Affects Tomato Colour
Tomatoes need warmth to ripen, but prolonged extreme heat can interfere with pigment development.
Red tomatoes develop their colour largely through pigments including lycopene. When fruit temperatures remain too high, colour development may slow or become uneven.
During a heatwave, full-sized tomatoes may:
Remain green
Develop yellow or orange areas
Ripen very slowly
Soften before achieving their expected colour
Develop sunscald on exposed surfaces
Retain healthy foliage, maintain consistent soil moisture and reduce extreme greenhouse temperatures.
Ripening often resumes when conditions become more moderate.
Internal White or Hard Tissue
A tomato may appear reasonably ripe outside but contain white, pale or hard areas inside.
Possible causes include:
Uneven ripening
Excessive heat
Nutrient imbalance
Poor growing conditions
Variety characteristics
Feeding damage from certain pests
Small amounts of firm white tissue can be cut away. A fruit that is extensively hard, unpleasant or showing internal decay should be discarded.
Could a Pest Cause Uneven Ripening?
Some sap-feeding pests pierce tomato fruit and disrupt normal development.
Damage may appear as:
Pale spots
Yellow areas
Cloudy patches beneath the skin
Hard white tissue
Small puncture marks
Distorted fruit
Inspect the fruit surface and nearby foliage for insects.
Pest damage is more likely when individual feeding marks are visible. Heat-related ripening problems tend to affect broader areas or several fruits exposed to similar conditions.
Uneven Ripening or Disease?
Physiological ripening problems usually produce firm areas without active decay.
Disease is more likely when the fruit develops:
Expanding dark lesions
Soft or water-soaked tissue
Mould
Sunken spots
Oozing
A foul smell
Related lesions on leaves or stems
A damaged tomato may experience both problems. Physiological injury can create an entry point for decay organisms.
What Is Catfacing?
Catfacing produces deep folds, scars, holes or distorted tissue at the blossom end of a tomato.
It begins while the flower is developing and is often associated with:
Cold conditions during flowering
Abnormally formed or fused flowers
Disturbance of flower development
Excessive nitrogen
Herbicide injury
Large-fruited varieties
Catfacing is not contagious. The fruit may still be usable if it develops normally and the scarred areas remain dry and free from decay.
Irregular cavities can trap moisture and dirt, so inspect and clean the fruit carefully.
What Is Zippering?
Zippering appears as a thin brown scar extending down the side of a tomato, sometimes with small cross-marks resembling a zip.
It occurs when part of the flower remains attached to the developing fruit and creates a scar as the tomato expands.
The mark is usually cosmetic. The fruit can normally be used if the skin remains sound and no decay develops.
Why Tomatoes Develop Growth Cracks or Scars
Scars can form when young fruit is damaged by:
Flower parts
Rubbing against stems or supports
Hail
Wind
Insect feeding
Rapid growth
Earlier cracking that has healed
A dry, stable scar is usually less concerning than a lesion that continues enlarging or becomes soft.
Why Tomatoes Become Misshapen
Fruit shape is influenced by both genetics and conditions during flowering.
Misshapen tomatoes may result from:
Fused or unusually large flowers
Cold weather during flower development
Incomplete pollination
Physical damage
Variety characteristics
Herbicide exposure
Pest feeding
Catfacing
Irregular shape alone does not make a tomato unusable.
Why Tomatoes Have Hollow Spaces
Some fruit develops with hollow areas and relatively little gel around the seeds. This is sometimes described as puffiness.
Possible contributing factors include:
Incomplete pollination
Temperature stress
Inadequate light
Irregular moisture
Nutrient imbalance
Poor seed development
The fruit may feel lighter than expected. It is often still usable, although the texture may be less satisfactory.
Why Tomato Skins Become Tough
Thick or tough skins may be a natural characteristic of the variety.
They may also become more noticeable when plants experience:
Hot, dry conditions
Irregular watering
Intense sunlight
Slow fruit growth
Extended time on the plant
Cherry tomatoes and varieties bred for storage or resistance to splitting may naturally have firmer skins.
Why Tomatoes Split After Picking
Fruit that has already absorbed a large amount of water may continue developing a crack after harvest. Fully ripe tomatoes can also split from pressure during handling or storage.
Handle ripe fruit gently and avoid stacking heavy tomatoes on top of one another.
Use damaged fruit promptly and check it carefully for decay.
What to Do When Heavy Rain Is Forecast
If ripe or nearly ripe tomatoes are on the plants after a dry period:
Harvest fruit that has begun changing colour.
Pick fully ripe tomatoes promptly.
Check supports for heavy trusses.
Ensure containers can drain freely.
Do not add unnecessary irrigation before the rain.
Inspect fruit after the weather clears.
Use newly cracked tomatoes quickly if they remain sound.
Harvesting at the first stage of colour change does not prevent the fruit from ripening indoors.
What to Do During Extreme Heat
To reduce fruit damage:
Maintain consistent soil moisture
Mulch the root zone
Ventilate covered spaces fully
Retain healthy foliage
Provide light temporary shade where necessary
Avoid severe pruning
Support exposed branches
Harvest ripe fruit promptly
Monitor exposed fruit for sunscald
Do not repeatedly wet the foliage and fruit in an attempt to cool them without considering humidity and disease risk.
Should Damaged Fruit Be Removed?
Remove fruit that is:
Rotting
Mouldy
Extensively split
Leaking
Severely pest-damaged
Unlikely to remain usable
This prevents the plant from continuing to support badly damaged fruit and reduces opportunities for pests and decay.
Fruit with a small, dry scar or superficial crack can remain on the plant if it is monitored closely. Harvest it as soon as it reaches a usable stage.
Should Leaves Be Removed Around Ripening Tomatoes?
Remove only leaves that genuinely need to go.
Useful reasons include:
Clear disease
Extensive damage
Natural yellowing
Contact with the soil
Severe overcrowding that prevents airflow
Leaves manufacture the sugars used in fruit development and protect tomatoes from intense sunlight.
Removing large amounts of foliage to expose fruit does not guarantee faster ripening and may cause:
Sunscald
Uneven ripening
Higher fruit temperatures
Slower development
Reduced plant vigour
Where removal is needed, take only two or three leaves at a time.
A Quick Tomato-Fruit Checklist
Cracks run down from the stalk
This is radial cracking, commonly associated with rapid water uptake after dry conditions.
Cracks form circles around the stalk
This is concentric cracking, often influenced by moisture changes and variety.
Many fine lines cover the skin
This may be rain checking caused by moisture, humidity or fruit remaining ripe on the plant.
A pale patch appears on the sunny side
This is probably sunscald.
The shoulders remain green or yellow
Consider variety, high fruit temperature, intense sunlight and uneven ripening.
The fruit has deep folds at the blossom end
This is probably catfacing caused during flower development.
A thin scar runs down the fruit
This may be zippering and is usually cosmetic.
Fruit contains hard white areas
Consider uneven ripening, heat, nutrient imbalance or sap-feeding pests.
A damaged area is soft and spreading
Investigate secondary decay or fruit disease.
Preventing Tomato Fruit Problems
The most useful preventive measures are:
Maintain reasonably consistent soil moisture
Water deeply
Use organic mulch
Provide adequate root space
Feed moderately
Retain healthy foliage
Prune gradually
Support stems and heavy trusses
Ventilate greenhouses and polytunnels
Reduce extreme heat where practical
Harvest ripe and colour-breaking fruit promptly
Choose varieties suited to the growing conditions
No season produces entirely perfect tomatoes. Weather can cause cracking, heat can delay colour and a single broken branch can expose fruit to strong sunlight.
Most physiological fruit problems do not threaten the entire plant. Identify the cause, protect the remaining crop and use safely damaged fruit promptly where appropriate.
For complete advice on growing healthy tomato plants from sowing through to harvest, return to How to Grow Tomatoes: Complete Guide.
