Why are my plant's leaves turning yellow?

Yellowing is a symptom, not a diagnosis. Where and how the yellow appears tells you a lot about the cause.

By Clara Hayes

Start with one question: which leaves?

Look at where the yellowing is happening. One old leaf at the bottom turning yellow now and then is normal: plants shed their oldest leaves as they grow. Many leaves at once, new leaves, or yellowing with other symptoms is worth investigating.

1. Overwatering

Clues: soft, limp yellow leaves, often starting low on the plant; soil that stays wet; sometimes a sour smell.

What to do: let the soil dry out more between waterings, make sure the pot drains, and empty saucers. If the stem base is soft, check the roots for rot.

2. Underwatering

Clues: yellow leaves that turn dry and crispy, drooping, soil pulling away from the pot's edges.

What to do: soak the plant thoroughly. If water runs straight through bone-dry soil, set the pot in a basin of water for 20–30 minutes so the soil can rehydrate from below.

3. Not enough light

Clues: gradual yellowing of lower leaves, pale new growth, long stretched stems leaning toward the window.

What to do: move the plant closer to a window or add a grow light. Remember that watering needs drop in low light, so this often goes hand in hand with overwatering.

4. Nutrient shortage

Clues: older leaves yellowing evenly across the plant, slow growth, in a plant that hasn't been repotted or fed in a long time.

What to do: during spring and summer, use a balanced houseplant fertilizer at the strength on the label. More isn't better: too much fertilizer can burn roots and cause brown leaf edges.

5. Temperature stress

Clues: sudden yellowing or leaf drop after a move, near a cold window, a draft, or a heat source.

What to do: keep the plant in a stable spot away from radiators, air conditioning vents and drafty doors.

6. Pests

Clues: yellow speckling or stippling, sticky residue, fine webbing, or visible insects under the leaves.

What to do: isolate the plant, rinse the leaves, and treat according to the pest (our free guide has a quick reference table).

Should I cut off yellow leaves?

A leaf that has turned fully yellow won't turn green again. You can remove it with clean scissors to keep the plant tidy and help you notice new problems sooner. Focus on fixing the cause rather than just removing leaves.

A quick way to narrow it down

You noticeCheck first
Soft yellow leaves, wet soilOverwatering and drainage
Crispy yellow leaves, dry soilUnderwatering
Pale, leggy growthLight
Speckles or stickinessPests
Sudden change after a moveTemperature and drafts

More reading: all articles.