Tomato: flowers dropping without setting fruit

What it is likely to be on tomato

1. Blossom drop

   Candidate 1very common on this plant

   ·source

   Sourced guidancehigh confidence

   • University of Minnesota Extension — University of Minnesota: Tomato — blossom drop

   Checked 2026-08-13

   Open flowers dropping from the plant without setting fruit, leaving a bare stalk. In tomatoes, peppers and chillies it is almost always temperature: pollen is sterile above roughly 30 °C and below roughly 13 °C, so the flower opens, fails to pollinate and is shed. It is a fault in the conditions rather than in the plant.

   Points towards it

   • · pollen is sterile above roughly 30 °C and below roughly 13 °C, so a temperature extreme while the flowers were open is the direct cause
   • · an unventilated greenhouse reaches the sterilising temperature far more readily

   Argues against it

   • · the compost is dry, and a plant short of water sheds flowers for that reason instead — the fix is different

   Check this next

   Match the drop against the weather over the previous week. Blossom drop follows a hot spell or a cold snap by a few days and stops when temperatures settle, which no nutritional cause does.

   What to do now

   Ventilate and shade under glass, or delay planting out until nights are reliably warm. Nothing applied to the plant will fix this — later trusses set normally once conditions settle. Tapping the trusses at midday helps where still air rather than temperature is the limit.

   ·source

   Sourced guidancehigh confidence

   • University of Minnesota Extension — University of Minnesota: Tomato — blossom drop

   Checked 2026-08-13

2. Underwatering

   Candidate 2common on this plant

   ·source

   Sourced guidancemoderate confidence

   • Royal Horticultural Society: Watering

   Checked 2026-08-13

   Easier to correct than overwatering and easily confused with it, because a plant short of water and a plant drowning both wilt. The distinguishing observation is not the plant at all — it is the compost, and it takes two seconds to check.

   Points towards it

   • · the compost is dry, and a plant short of water sheds flowers first
   • · water shortage affects the whole plant

   Argues against it

   • · the compost is wet, so water shortage is not the reason the flowers are dropping — this rules it out entirely.

   Check this next

   Check the compost at depth before blaming the weather. A plant dropping flowers with dry compost and some wilting is short of water; one dropping them with moist compost after a hot week is not.

   What to do now

   Water thoroughly and keep it even. Flowers are shed before leaves when a fruiting plant runs short, so this is an early warning rather than a late one.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Watering

   Checked 2026-08-13

3. Natural fruit drop

   May be normalcommon on this plant

   ·source

   Sourced guidancemoderate confidence

   • Royal Horticultural Society: Tomatoes — flower and fruit problems
   • Cornell Fruit Resources — Cornell University, College of Agriculture and Life Sciences: Tomato — flower and fruit set

   Checked 2026-08-13

   A tree or plant shedding some of the fruit it has set, usually a few weeks after flowering. It is self-thinning rather than a failure: far more flowers are pollinated than the plant can carry to maturity, and the fruit that fall are the ones it has decided against. Apples do it so reliably in early summer that the event has a name.

   Points towards it

   • · only the last flowers on each truss go, while the first three or four on the same truss set normally — which is the signature and is the opposite of a whole-plant failure
   • · no event is needed and none will be found, because the plant is balancing its own crop load
   • · a well-watered plant in good condition dropping a few flowers is regulating rather than suffering
   • · it happens on trusses at any height once the plant is carrying a full crop

   Argues against it

   • · every flower on every truss going is not the plant choosing, and points at blossom drop or at drought
   • · a tomato that has dried out sheds flowers for a reason that needs fixing

   Check this next

   Count what is left on the truss rather than what has fallen. Natural shedding takes the last two or three flowers at the tip of a truss whose first four or five have already set into visible fruit, on a plant that is otherwise growing strongly — and it happens on truss after truss as the plant fills up. If a whole truss has gone with nothing set on it, or if the flowers are dropping from the very first truss, the plant is being stopped by something else and the answer lies in the temperature, the watering or the pollination.

   What to do now

   Nothing to do. A tomato sets what it can carry and sheds the rest, and a plant filling four or five fruit per truss is doing well — trying to save the last flowers by feeding, misting or adjusting the greenhouse simply changes the conditions for the fruit that did set. Keep the watering steady and the feeding regular, tap the flowering trusses or open the door on warm days to move pollen, and judge the plant on the fruit it is carrying rather than on the flowers it has dropped.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Tomatoes — cultivation
   • Cornell Fruit Resources — Cornell University, College of Agriculture and Life Sciences: Tomato — fruit set and crop load

   Checked 2026-08-13

Narrow it down

This page lists everything at once, which is the right shape for reading and the wrong shape for deciding. The interactive tool asks one question at a time, starting with whichever would separate these causes fastest, and stops as soon as further answers would not help.

Opens with the plant and the symptom already set. Nothing you answer is stored or sent anywhere — the answers live in the address bar and nowhere else.

What this does not cover

These are the causes GrowingHQ holds rules for on tomato — not every cause there is. Where several problems look alike, the honest answer is often that they cannot be told apart by eye, and a page that named one would be guessing. If none of the above fits, the general flowers dropping without setting fruit page lists causes across all plants, and the Tomato profile lists the problems it is prone to.