Brown edges with no halo — water or humidity. Round brown spots with a yellow ring — fungal infection. The two look similar at a glance and get treated the same way far too often. That single mistake — reaching for a fungicide when the problem is actually at the roots — is why many garden problems persist through an entire season.
The pattern on the leaf tells you what to look for next:
Dry brown tip or corner — underwatering or low air humidity. Check the soil: if it’s bone dry several centimetres down, this is the cause.
Round brown spots with yellow halo — leaf spot fungus. Improve air circulation, avoid overhead watering, remove affected leaves.
Whole leaf pale yellow-green with brown margins — insufficient light. Move to a brighter position before assuming a nutrient problem.
One half yellow, one half green — overwatering or waterlogged roots. Let the soil dry fully before watering again and check drainage.
Concentric brown-and-yellow rings scattered across the leaf — active fungal infection. Treat with a copper-based fungicide and improve ventilation.
Irregular holes or eaten margins — insect damage. Check the undersides of leaves and the soil surface for slugs, caterpillars, or vine weevil.
Diagnose before you treat. Looking at the pattern first, then checking the watering, then checking the soil — in that order — avoids most mistakes.
A single damaged leaf is not a dying plant.