Yellow Leaves: Causes & Fixes

Yellow leaves — chlorosis — are a symptom, not a diagnosis. The good news: it almost always comes down to one of five root causes. Here's how to tell them apart.

1. Overwatering (most common)

If the yellowing starts on lower leaves and the soil feels wet days after watering, the roots are drowning. Waterlogged soil starves roots of oxygen and they start to rot, so the plant can't move nutrients up. Let the top few centimetres dry, check drainage, and consider repotting into fresher, airier mix.

2. Underwatering

Bone-dry soil, crispy edges, and drooping stems before the yellow sets in? That's the opposite problem. Soak the pot thoroughly, let it drain, and reset your schedule.

3. Light stress

Sudden bright sun bleaches leaves pale yellow with brown patches. Too little light turns whole leaves an even pale-yellow-green — the plant is running out of chlorophyll to make.

4. Nutrient deficiency

Nitrogen deficiency shows as a uniform pale-yellow starting on old leaves. Iron deficiency yellows the space between still-green veins on new leaves. A balanced liquid feed at half strength every 2–4 weeks in the growing season fixes most cases.

5. Pests or disease

Spider mites, thrips, and scale drain plants and leave yellow speckling. Check the undersides of leaves and stem joints. Fungal leaf spot causes yellow halos around darker patches.

Not sure which of the five you're looking at? Photograph the worst leaf against a plain background in PlantMe — the disease-diagnosis model matches the pattern and gives you the fix.