After heavy summer rain, tomatoes can suddenly develop cracks. At the same time, leaves remain wet for a long time, heavy shoots may topple and moisture can accumulate in dense foliage. A hasty all-around pruning won't help now; instead carry out a calm inspection of the fruits, supports and site.
Why tomatoes split after rain
If the plant takes up a lot of water very quickly after a dry spell, the fruit's growth can be faster than the skin can give. Variety, ripeness and water supply play a role. Consistent watering and a rain-protected, airy location can reduce the risk, but it cannot be completely prevented outdoors.
Check immediately after the heavy rain
- Check water drainage: Empty saucers and ensure that pot drainage holes are not clogged.
- Inspect the fruits: Separate split, rotten or mouldy fruits from healthy ones.
- Support shoots: Replace loosened ties and gently tie up heavy fruit clusters.
- Avoid contact with the soil: Leaves and fruits should not remain lying on wet soil.
- Allow air: Do not push plants closer together and ventilate sheltered areas.
What to do with split fruits?
Fruits with mould, rot, an unpleasant odor or heavily changed spots should be discarded and not tasted. A freshly split fruit without visible spoilage must be processed quickly; check and wash it thoroughly and cut away the damaged area generously. When in doubt: do not use.
Damaged fruits should not be left on the plant because open wounds promote further decay. They also do not belong on an open compost heap if clear disease or rot symptoms are already visible.
Don't further stress wet leaves
Do not automatically water after heavy rain. Check the soil a few centimetres deep. In a pot the surface may already look dry while the root zone is still wet. When you water again later, apply the water directly to the soil and, if possible, not over the leaves.
Radically removing many healthy leaves is not a good immediate measure. First remove only heavily damaged or diseased plant parts with clean tools. ARCHE NOAH provides guidance on recognising diseases.
Prepare for the next rain
- Use pots with free drainage holes and suitable drainage.
- Tie tomatoes securely before thunderstorms are forecast.
- Even in a covered location, ensure air movement.
- Keep the soil as evenly moist as possible instead of alternating between very dry and very wet.
- Harvest ripe fruits promptly.
If heavy heat follows the rain again, our article helps How to water balcony plants properly in heat. Larger gardening tasks should also be done during cool times of day, as described in Gardening in the heat described.
Sources and further information
- ARCHE NOAH: Diseases and pests in tomatoes
- ARCHE NOAH: Cultivation and crop management
- Federal Association of Austrian Gardeners: Tomatoes and weather
Article image: AI-generated symbolic image.
