Brown leaves on houseplants are caused by several distinct problems, each of which produces a characteristic pattern of browning. Here's the top four causes.
Low Humidity or Underwatering
Displayed through: Brown leaf tips and edges
Brown, crispy tips that spread inward along the leaf margins are the classic sign of low humidity in the UK. Most tropical houseplants, Calatheas, Marantas, Ferns, Anthuriums, evolved in humid environments and struggle with the dry air produced by central heating in UK homes in winter. The humidity indoors often drops to 30 to 40% during the heating season, well below the 50 to 70% that most tropical foliage plants prefer.
Grouping plants together raises the local humidity around them. For long-term improvement, try using a humidifier. See our guide on what humidity houseplants prefer for practical solutions.
Brown tips caused by underwatering look similar, dry and crispy, but the whole leaf typically shows stress (limp, pale) and the compost is bone dry. If the compost is moist and the plant is still getting brown tips, humidity is almost certainly the cause.
Overwatering or Root Rot
Displayed through: Soft brown patches
Soft, yellowing brown patches, particularly on lower leaves, are the typical presentation of overwatering. The leaf tissue becomes waterlogged and breaks down, producing a soft, dark brown discolouration that often spreads from the base of the leaf outward. Unlike the crispy dryness of humidity damage, these patches feel limp or slightly mushy.
If the compost has been consistently wet and the lower leaves are showing soft browning, overwatering and root rot should be your first suspect. Check the roots: overwatered roots are brown and mushy rather than firm and white. See our guide on what root rot is and how to prevent it for what to do if you find damaged roots.
Sun Scorch
Displayed through: Bleached or papery brown patches
Direct sunlight through a south or west-facing window scorches tropical houseplant leaves, producing bleached, papery, or tan-coloured patches, usually on the parts of the leaf most directly exposed to the sun. Unlike humidity damage, scorch marks tend to be in the middle of a leaf rather than at the tips, and they appear after a plant has been moved to a brighter position or after the sun angle changes in spring.
The fix is straightforward: move the plant back from the window or filter the light with a sheer curtain. Scorched leaves do not recover, but new leaves will be undamaged once the plant is no longer in direct sun. See our guide on how to tell if a plant is getting too much light.
Cold Damage and Draughts
Displayed by: Dark blotches
Cold draughts from windows, doors, or air conditioning units cause rapid browning, often appearing as dark blotches or a sudden collapse of leaf tissue. Unlike the gradual progression of humidity damage, cold damage can appear within hours of exposure. Tropical plants are particularly vulnerable to temperatures below 12 to 15°C. A plant placed near a single-glazed window in a UK winter may be experiencing temperatures at the leaf surface well below the room temperature.
The fix is to move the plant away from cold windows and draughts, particularly through November to February. Even a metre away from the glass makes a significant difference on cold nights. See our guide on draughts and radiators.
How to Remove Brown Leaves and Tips
Once leaves or leaf tips have browned, they will not recover. You can trim brown tips with sharp scissors following the natural curve of the leaf tip: this produces a more natural appearance than a straight horizontal cut. Use clean, sharp scissors and wipe the blades with rubbing alcohol before and after to avoid transferring any pathogens.
Do not remove leaves that are more than half still healthy: they continue to photosynthesise and support the plant. Remove leaves only when the majority of the leaf has browned or died.