Skip to content
Grow In Backyard
Plant Diseases

Black Spots on Cherry Tomatoes: Where It Sits Tells You

A black spot at the blossom end, on the shoulder, or anywhere on the skin means three different problems with three different fixes. Position is the test.

By Zakaria 3 min read Save to Pinterest — opens Pinterest in a new tab
A truss of ripe cherry tomatoes with clean unblemished skin, calyxes still attached
Photo: C.P.Storm, CC BY 2.0, via Flickr
On this page

Where the spot sits is the whole diagnosis. A black patch on the bottom of a cherry tomato, a spot anywhere on the skin, and darkening on the shoulder are three unrelated problems with three different fixes.

Identify it by position

This table answers the question on its own
Blossom end rotAnthracnoseSunscald / splitSooty mould
WhereBlossom end, dead centreAnywhere on the skinShoulder, sun sideAnywhere
ShapeOne sunken patchCircular, concentric ringsLeathery, often crackedFlecks and films
Flesh beneathDry and firmSoft and wateryDry, toughUnaffected
Wipes off?NoNoNoYes
Contagious?NoYesNoNo
Eat it?Cut the end offNo — bin itCut it outYes, wash it

One test before anything else

Rub it. If the black comes away on your thumb and the skin underneath is intact, you are looking at sooty mould growing on aphid honeydew — a pest problem, not a fruit disease.

Blossom end rot is a plumbing problem

It is not a calcium shortage in your soil in all but the most unusual cases. It is the plant failing to deliver calcium to the fastest-swelling fruit, and that happens when the soil swings between wet and dry. Calcium moves with water; interrupt the water and the fruit at the end of the queue misses out.

  • Mulch, to even out what the soil does between waterings
  • Water on a schedule, not when the plant looks thirsty
  • Watch containers and grow bags closely — they are where it happens most
  • Expect a whole truss to show it at once, because they all went through the same dry spell
  • Later trusses coming clean is the sign that the fix has worked

Eggshells and calcium sprays are mostly wasted effort

They address supply. The failure is transport. Steady watering is the intervention that actually changes the outcome.

Anthracnose: the one to remove

A sunken circular spot with faint concentric rings and soft flesh underneath, on ripening fruit. Warm wet weather and fruit touching the ground make it far more likely.

  • Pick affected fruit off and bin it — not onto the garden compost heap
  • Pick ripe fruit promptly; the longer it hangs in wet weather, the more exposure it gets
  • Keep trusses off the soil with support
  • Water at the base, never over the fruit
  • Rotate — the fungus overwinters in debris in the same ground

Splits that turn black

The split comes first, from a surge of water into nearly-ripe fruit after a dry spell. Within a day or two in warm weather, fungi and bacteria colonise the open wound and the edges blacken.

Even moisture prevents it. When a wet spell is forecast and the fruit is close, pick slightly early — cherry tomatoes finish ripening perfectly well off the plant.

Common questions

What causes black spots on cherry tomatoes?

Where the spot sits identifies it. A sunken dark patch centred exactly on the blossom end, opposite the stem, is blossom end rot — a calcium delivery failure caused by uneven watering, not a disease and not contagious. Small sunken circular spots anywhere on the skin that develop concentric rings and go soft are anthracnose, a fungal infection of ripe fruit. Dark leathery patches on the shoulder of the fruit near the stem, often with cracking, are sunscald or the aftermath of splitting. And tiny black flecks that wipe off are usually sooty mould growing on aphid honeydew.

Can you eat cherry tomatoes with black spots?

Blossom end rot is safe — cut the dark end away and the rest of the fruit is fine, though on a cherry tomato there is often not much worth saving. Fruit with anthracnose should be discarded rather than eaten or composted on the heap you use for the garden, because the fungus survives and overwinters. Any tomato that has gone soft, smells fermented or has mould growing on it goes in the bin regardless of the original cause.

How do I stop blossom end rot on cherry tomatoes?

Water consistently. The cause is almost never a shortage of calcium in the soil — it is the plant failing to move calcium to the fastest-growing fruit, which happens when the soil swings between wet and dry. Mulch to even out moisture, water on a regular schedule rather than when the plant looks thirsty, and be especially careful with containers and grow bags, which dry out fast. Calcium sprays and eggshells do very little, because the problem is transport rather than supply.

Does blossom end rot spread to other tomatoes?

No. It is a physiological disorder, not an infection, so an affected fruit cannot pass it to its neighbours. What does happen is that several fruits on the same truss show it at once, because they all went through the same dry spell at the same stage of swelling. Later trusses on the same plant are usually clean once watering steadies, which is a good sign that the fix is working.

What does anthracnose look like on a tomato?

It starts as a small circular spot on ripe fruit that becomes sunken, darkens and develops faint concentric rings, often with tiny dark dots in the centre. The flesh under the spot goes soft and watery. It is a disease of ripening fruit specifically, so green tomatoes that look clean can develop it after picking. Warm wet weather and fruit touching the soil make it far more likely.

Why do my cherry tomatoes split and then go black?

Splitting comes from a sudden surge of water into fruit that is already nearly ripe, typically heavy rain or heavy watering after a dry spell. The split itself is not a disease, but it is an open wound on a sugary fruit, and fungi and bacteria colonise it within a day or two in warm weather — which is the black you see. Even moisture prevents the split, and picking slightly early during an unsettled spell saves the crop.

Backyard Weekly

Know what to plant, week by week

Join the weekly email for seasonal jobs, fixes for what is going wrong, and gear worth buying.

Not ready to subscribe? The planting calendar is free and needs no email.

By subscribing you agree to our privacy policy. Grow In Backyard will never sell your address.

Keep reading