GrowingHQ
Fruit

Dark sunken patch at the bottom of a fruit

A flattened, leathery, brown-black area at the flower end of a tomato, pepper or courgette — the end away from the stalk. It usually appears on the first fruits to set and while they are still green.

Described view

Two green tomatoes side by side at the same scale: one with the flat, dry, leathery, sharply-bounded sunken patch of blossom end rot at the flower end, and one with the greasy, spreading, brown-marbled lesion of late blight that has no clear edge and is not confined to the flower end

What causes it, and how to tell them apart

Work down the list making the observation under each heading. GrowingHQ will not guess which one you have — the observation is the answer.

  1. Blossom end rotvery common
    source

    Sourced guidancehigh confidence

    • Home and Garden Information Center — Clemson Cooperative Extension: Tomato disorders

    Checked 2026-08-13

    How to tell

    The patch is dry and leathery rather than soft or mouldy, it is at the flower end specifically, and there is no fungal growth on it. Nothing is spreading between fruits — plants next to each other with identical watering are affected identically, which is the giveaway that this is a disorder and not a disease.

    source

    Sourced guidancehigh confidence

    • Royal Horticultural Society: Blossom end rot

    Checked 2026-08-13

    If it is this, do first

    Even out the watering rather than adding anything. Remove the affected fruit; later fruit on the same plant is usually sound once the supply is steady.

    source

    Sourced guidancehigh confidence

    • Royal Horticultural Society: Blossom end rot — prevention

    Checked 2026-08-13

  2. Late blightoccasional
    source

    Horticultural consensusmoderate confidence

    • Royal Horticultural Society: Tomato blight

    Checked 2026-08-13

    How to tell

    Blight on fruit is a firm brown marbled rot that can start anywhere on the fruit, not only at the flower end, and it comes with dark lesions on leaves and stems. Fruit damage with no leaf damage is not blight.

    source

    Sourced guidancehigh confidence

    • Royal Horticultural Society: Tomato blight — symptoms

    Checked 2026-08-13

    If it is this, do first

    Remove and dispose of affected fruit, and check the foliage. If the leaves are lesioned too, the plant will not recover.

    source

    Sourced guidancehigh confidence

    • Royal Horticultural Society: Tomato blight

    Checked 2026-08-13

Where GrowingHQ holds more for one plant

This page lists the causes across every plant. The plants below are the ones where something about that plant changes the answer — different candidates, or a different observation that separates them.

Vegetables

Commonly reported on