Why are my plant's leaves turning yellow?
Last reviewed: October 2026
Quick answer
Yellow leaves are usually a sign of stress from the plant's surroundings, and too much water is the most common cause indoors. Too little water, poor light, too little fertilizer and cold drafts can also do it. One old lower leaf yellowing now and then is normal.[3][6][1]
Causes and how to tell them apart
Normal aging of old leaves[1][2]
How to tell: Only the odd lower leaf on a mature plant yellows and falls, and the rest of the plant looks healthy.
Overwatering or poor drainage[3][4][5]
How to tell: Lower and inner leaves yellow or wilt, and the soil stays wet. Old and new leaves may yellow and drop together, and roots may be dark and mushy.
Underwatering[5]
How to tell: Older leaves at the base yellow and fall first, and the soil is very dry a few centimetres down. Leaf edges may also be brown and crispy.
Too little light[5]
How to tell: Growth is weak and spindly with pale leaves, and the lower leaves turn yellow and fall.
Too much direct sun[1][5]
How to tell: The plant sits in strong midday sun, such as a south-facing window in summer, and leaves look washed out or scorched.
Too little fertilizer[6][5][1]
How to tell: The plant has been in the same pot for years, growth is poor, and leaves lose color.
Cold, heat or drafts[6][5]
How to tell: Yellowing began after a move, a cold trip home from the store, or near a door, window or heat vent.
What to do, step by step
- Push a finger a few centimetres into the soil. If it is very dry, water. If it is wet, hold off.[5]
- Tip the plant out of its pot and look at the roots. If they are brown, soft and rotted, you need to water less.[1]
- Pour off any water that collects in the saucer under the pot, and water thoroughly only when the plant needs it.[4]
- If the pot is too big for the roots, repot into a smaller container.[1]
- Move the plant to a better spot. Change light levels gradually when you move it.[6][1]
- If growth is poor, feed with a suitable liquid fertilizer during the growing season.[5]
- Cut off leaves that are completely yellow, because they will not recover.[5]
How to prevent it
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- On gardenia, if upper leaves turn yellow but stay firm, the cause may be excess calcium or long use of hard water.[1] Pet safety: Gardenia
Frequently asked questions
Why are only the bottom leaves of my plant turning yellow?
One lower leaf yellowing and falling on a mature plant is normal. If many leaves yellow, look at watering, light and temperature.[1]
Is my plant overwatered or underwatered?
Check the soil and roots. With underwatering, older leaves at the base yellow first. With overwatering, old and new leaves yellow and drop together, and roots may be dark and mushy.[5]
Should I cut off yellow leaves?
Cut off leaves that are fully yellow, since they will not recover. Keep leaves that are mostly green until the plant grows new ones.[5]
Related plant problems
Sources
- Royal Horticultural Society (RHS): Leaf damage on houseplants
- Iowa State University Extension: Diagnosing Houseplant Problems from Improper Environmental Conditions
- University of Maryland Extension: Yellowing Leaves on Indoor Plants
- University of Maryland Extension: Overwatered Indoor Plants
- Royal Horticultural Society (RHS): How to help a poorly houseplant
- Iowa State University Extension: What causes leaves on my houseplant to turn yellow or brown and drop off?
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Sources: the university extension and horticultural society pages listed above. Last reviewed October 2026.