Plant problem

Brown or black leaf spots

Leaf spots describe damage, not one cause.

Brown or black leaf spots need a close look at their pattern and progression. Inspect leaf surfaces, recent moisture conditions, and pest evidence before treating a spot as a specific disease.

Pattern and spreadCompare old and new spots

Leaf surfacesInspect for visible pests

UrgencyPrompt if spreading

Check causes See related symptoms

Green houseplant leaf with several dark brown circular spots in a wide indoor plant photograph — **Check whether spots are spreading**

At a glance

First possibilityPossible root rot or root-zone decay

Also comparePossible pest pressure

Root-zone moistureCheck below the surface

Acting pacePrompt if spreading

Quick brown or black leaf spots guide

Check first

Photograph or note the size, colour, shape, and location of spots so you can tell whether they are spreading.
Inspect both leaf surfaces and nearby stems for insects, webbing, sticky residue, or unusual growth.
Check whether leaves stay wet, plants are crowded, or the root zone remains wet, then compare the observations with the plant's own care guidance.

Common causes

Possible root rot or root-zone decay
Possible pest pressure

Good to know

Old mechanical damage should not keep expanding.
Raised pests and flat tissue damage need different next checks.
Wet-looking spots on new growth deserve prompt observation.

What to do next

Photograph the current pattern so new spread is easier to see.
Inspect both sides of nearby leaves in good light.
Check moisture and avoid wetting foliage unnecessarily.
Separate the plant if spots spread or visible pests are confirmed.

When to act fast

Many spots that enlarge, join together, reach stems, or affect new growth need prompt inspection and separation from nearby plants while you assess the cause.
Leaf spots paired with extensive leaf drop, wet-looking tissue, or rapid loss of vigour are not a routine cosmetic issue; avoid delaying a closer assessment.

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Observation checker

Compare what you can confirm

Add only observations you are confident about. Unknown answers can stay blank, and the result remains a shortlist of checks rather than a diagnosis.

Common questions

Frequently asked questions

Do brown or black spots always mean a fungal disease?

No. A spot pattern alone cannot confirm a cause. Record its shape and progression, inspect for pests, and review moisture and recent conditions before choosing a treatment.

Should I remove a leaf with spots?

Removing a clearly affected leaf can be part of tidying or limiting damaged material, but it does not identify the cause. Use clean tools and continue to observe the plant.

Should I spray a product for leaf spots immediately?

No. First identify the problem as far as possible and use only products labelled for the plant and indoor setting, following the label exactly.

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