Why Are My Houseplant Leaves Turning Yellow? 7 Causes and Fixes

1. Overwatering (the most common cause)

If lower leaves are yellow, soft, and fall off with a gentle pull — and the soil feels wet more than a day or two after watering — you are overwatering. Roots suffocate in waterlogged soil and stop taking up nutrients, which the plant shows in its oldest leaves first.

Fix: Let the top 2–3 cm (1 inch) of soil dry before watering. If drainage is poor, repot into a pot with holes and a chunkier mix.

2. Underwatering

Leaves turn yellow and then crispy, starting from the edges. Soil pulls away from the pot walls and feels bone-dry several centimetres down.

Fix: Bottom-water by sitting the pot in a tray of water for 20 minutes, then water normally on a more frequent schedule.

3. Too little light

Uniform yellowing across many leaves, often with long, stretched stems reaching toward windows, points to light starvation.

Fix: Move closer to a bright window or add a grow light for 8–12 hours a day.

4. Too much direct sun

Bleached yellow patches, sometimes with crispy brown centers, on the side facing the window are sunburn.

Fix: Move back from the window or add a sheer curtain.

5. Nutrient deficiency

Nitrogen deficiency yellows the oldest leaves first, while iron deficiency yellows the newest leaves between the veins. Both develop over weeks, not days.

Fix: A balanced liquid fertilizer at half strength every 2–4 weeks during growing season.

6. Root rot

Yellow leaves combined with a sour smell from the soil and black, mushy roots when you check the base.

Fix: Unpot, trim black roots with clean scissors, and repot in fresh dry mix. Hold off on water for a week.

7. Natural leaf drop

One or two older leaves per month turning yellow is normal. Ficus, calathea, and most large tropicals drop leaves as they grow.

How to tell which cause is yours

Three questions narrow it down in 30 seconds:

1. Which leaves? Oldest = overwatering or nutrients. Newest = iron deficiency. Whole plant = light.
2. Dry or mushy? Crispy edges = under. Soft and wet = over.
3. Pattern? Bleached patches on one side = light. Between-the-veins = nutrients.

When to use AI diagnosis

If the yellowing does not match any of the seven patterns above — or if it is spreading fast — snap a photo in the AI Plant Doctor app. The AI checks the leaf against hundreds of known plant problems and returns a treatment plan in seconds.