Blossom drop in tomatoes
When tomato blossoms fall off before fruit set, in most cases this is due to avoidable cultivation errors. Blossom drop often occurs on the first flower cluster and is an early warning signal from the plant that environmental conditions are not suitable.
Blossom drop – what exactly happens?
Tomato plants produce bisexual flowers that are generally capable of self-pollination. However, if pollination is unsuccessful or the plant is under stress, it actively detaches from the affected flowers—the fruit does not develop. Instead of investing energy into a fruit that is unlikely to succeed, the plant drops the flower cluster.
Possible causes of blossom drop
Lack of pollination
In protected cultivation (e.g. polytunnels, greenhouses), wind movement and insect activity are often missing. Without vibrations, the pollen remains in the anthers and the stigma is not pollinated.
Temperature stress
Temperatures below 12 °C or above 30 °C cause physiological stress. The plant aborts reproduction—flowers are the first to be sacrificed.
Nutrient imbalance
An excess of nitrogen promotes vegetative growth but inhibits the generative phase. Instead of fruit formation, the plant mainly produces leaf mass.
Unstable water supply
Strong fluctuations between drought and excessive moisture disrupt the plant’s water balance. In response to this stress, it drops unpollinated flowers.
Variety-specific susceptibility
Some varieties are more sensitive to unfavourable conditions, especially when flowering begins too early on still weakly developed plants.
Plant overload
If the plant has already set many fruits or is under continuous stress, it may no longer be able to supply all developing fruit. In such cases, it selectively aborts new flowers to prioritise existing fruits with nutrients.
Practical solutions
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Gently shake flowers daily, especially in protected cultivation
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Ensure stable temperatures and good ventilation
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From the start of flowering, use low-nitrogen but potassium-rich fertilisation
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Water regularly and appropriately – avoid waterlogging
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If early flowering occurs on weak plants: consider removing the first flower cluster
Blossom drop is not a serious problem, but rather an indication of unbalanced growing conditions. If the causes are identified and corrected in time, the plant will usually continue to develop normally—with successful fruit set on the subsequent flower clusters.