Lemon leaves turning yellow: causes and what to do
17 results in the diagnosis tree begin with yellowing leaves, 7 of them marked likely when the answers fit. They are ordered here for Lemon (Citrus x limon), using what its sources say about soil moisture, light, soil, watering and feeding and one problem recorded for it.
Sources last read 14 September 2026.
The lemon is a species of small evergreen tree in the Citrus genus of the flowering plant family Rutaceae. A true lemon is a hybrid of the citron and the bitter orange. Wikipedia, CC BY-SA 4.0
Native range: as a cultigen derived from artificial hybrids. (subtropical). Also sold as bergamot, bergamot orange, Chinese dwarf lemon, dwarf lemon, lemandarin and mandarin lime.
What Lemon’s sources say that bears on this
- Soil moisture
- Moist but well-drainedRHS · read 13 September 2026
- Light
- Full sunRHS · read 13 September 2026
- Soil
- Loam; pH Acid or NeutralRHS · read 13 September 2026
- Watering
- In the growing season they need lots of water plus small, regular doses of nitrogen fertilizer to boost growth and fruit size.NC State Extension · read 13 September 2026While growing in spring and summer, water generously and mist every day. Use a citrus fertiliser all year round as directed by the manufacturer; give little water in winter.RHS · read 13 September 2026
- Feeding
- In the growing season they need lots of water and frequent light doses of nitrogen fertilizer to boost growth and fruit size.NC State Extension · read 13 September 2026Use a citrus fertiliser all year round, following the manufacturer’s directions; water sparingly in winter.RHS · read 13 September 2026
How this shows up on a Lemon
Soft yellow leaves low on the plant, soil still wet
A sour smell from the compost is common on a lemon, and the leaves deepest inside the canopy come away when pulled. The surface may look dry while everything beneath it is not.
Its source calls for soil that is moist but well-drained. Past that, water in the pot displaces the air the roots need, and damaged roots then fail to supply the leaves above them.
Telling it apart: Whether the compost has dried at all since the last watering. A pot that has not dried in a fortnight is answering the question on its own.
RHS · read 13 September 2026Possible causes, likeliest first for a Lemon
Most likely too little water
Ranked higher because Lemon's recorded problems point this way.
- Moist but well-drained RHS · read 13 September 2026
Why: Soil dry two inches down, under lower leaves that are yellowing or leaves that are falling, is a lemon shedding what it cannot support.
What to try:
- Water until it runs from the drainage hole, then let the pot drain.Useful: pot with drainage holes
- If the water runs straight through a shrunken rootball, stand the pot in water for twenty minutes so the compost can take it up.
What would settle it: Water it thoroughly and look again the same evening. A thirsty plant firms up fast. One that does not has a root problem rather than a water problem.
Most likely too much water
Ranked higher because Lemon's recorded problems point this way.
- Moist but well-drained RHS · read 13 September 2026
- Loam; pH Acid or Neutral RHS · read 13 September 2026
Why: Soil that is wet two inches down, under leaves that are yellowing from the bottom or falling, points at roots that cannot breathe.
What to try:
- Hold off watering until the top two inches of soil are dry, and check again with a finger rather than by the calendar.Useful: moisture meter
- Empty any water standing in the saucer or the outer pot within half an hour of watering.Useful: pot with drainage holes
What would settle it: Lift the lemon out of its pot. Healthy roots are firm and pale; roots that have been wet too long are brown, soft and smell sour.
Most likely too little water
Ranked higher because Lemon's recorded problems point this way.
- Moist but well-drained RHS · read 13 September 2026
Why: Soil dry two inches down leaves the roots nothing to send up, and the leaf edges are the last tissue in line.
What to try:
- Water thoroughly, until it runs from the drainage hole.Useful: pot with drainage holes
- Check the soil with a finger every few days rather than watering on a fixed day.Useful: moisture meter
What would settle it: Water it thoroughly and watch the next new leaves. If they come in with clean edges under steadier watering, the edges were thirst.
Less likely for a Lemon, still possible
- Most likely not enough light
- Most likely short of nutrients
- Most likely a build-up of salts in the soil
- Most likely cold
- Nutrients are an unlikely explanation here
- Possibly root rot, in a pot that has stopped draining
- Probably too much water, but this is not settled
- Probably too much water
- Light and feeding are both plausible, and this does not separate them
- This may be ordinary leaf loss
- Possibly dry air
- The answers do not point at one cause
- Possibly too much direct sun
- Possibly too much direct sun, or feeding
Questions
- What usually causes yellowing leaves on a Lemon?
- For Lemon: most likely too little water, most likely too much water and most likely too little water.
- How can I tell which one it is on my Lemon?
- Where is the yellowing? The lowest leaves, working upward; New growth at the top, while older leaves stay green; Between the veins, the veins themselves still green; At the leaf tips and edges, browning as it goes; Patchy, only on the side facing the window.
- What do Lemon's sources say about its soil moisture?
- RHS: Moist but well-drained.
- What does this look like on a Lemon?
- A sour smell from the compost is common on a lemon, and the leaves deepest inside the canopy come away when pulled. The surface may look dry while everything beneath it is not. Telling it apart: Whether the compost has dried at all since the last watering. A pot that has not dried in a fortnight is answering the question on its own.
- Is Lemon safe to handle while I check it?
- Its sources list it as toxic to people. Wash your hands after handling the roots or sap, and keep trimmings away from pets.
Other plants that show yellowing leaves
AvocadoYellowing that begins at the leaves deepest inside the canopy
Chinese banyanFaded, yellow-white areas on the sunny side of the canopy
Coffee plantPale dry areas across the upper leaves only
Common figThe leaves deepest inside the canopy turn yellow and hang
Crape myrtlePale dry areas across the upper leaves only
Japanese mapleYellowing that begins at the leaves deepest inside the canopy
Something else wrong with the Lemon?
What this does not cover
This page orders a decision tree's results using a plant's sourced care. It has not seen your plant, its pot or its window, and two problems at once are common: that is the usual reason a confident answer turns out wrong. The questions in the diagnosis tool narrow it further than a list can.