Brown or pale spots on leaves
Spots on leaves have many causes, and the pattern narrows them down: a white powdery coating that rubs off points one way, flat dry patches facing the window point another, and dark spots with yellow halos point somewhere else again.
Do not jump to disease first. Watering, light, and pests explain most indoor spots, and fungal or bacterial infection is uncommon unless the plant recently came from outdoors or a greenhouse. When in doubt, remove one affected leaf, keep the plant isolated, and watch whether new leaves stay clean.
General beginner information only — not a substitute for advice from your local agricultural extension service. For edible plants, use only a product that is labelled for that particular edible crop, for indoor use, and follow any harvest interval on its label; try non-chemical steps first, and never use a product that is not labelled for indoor use on that plant.
Checklist to diagnose
- Does the coating rub off, or is it part of the leaf itself?
- Are spots only on the window-facing side, only on old leaves, or all over the plant?
- Is the mix wet or dry, and are leaves staying wet for long periods?
- Are there insects, webbing, or sticky residue on the undersides?
- Did the plant recently move to brighter light, outdoors, or a new spot?
Rescue steps
- For a white powdery coating, remove the worst leaves, improve air circulation around the plant, water at soil level so leaves stay dry, and keep the plant out of crowded, still corners.
- For flat dry patches facing the window, move the plant back from the glass or filter the light, and protect the remaining healthy foliage; scorched areas will not heal.
- For dark spots that keep spreading, remove affected leaves with clean scissors, clean the blades between cuts, and keep the plant away from neighbours until new growth stays clean.
- Check water and light before reaching for any spray: most spots improve when leaves stay dry and light is steady.
- If spots keep spreading fast, smell bad, or look wet and sunken, ask a local extension service or nursery to identify the problem from the whole plant rather than guessing from a photo.
When to give up
- Spots consume most leaves despite dry foliage, steady light, and removal of affected leaves.
- The stem itself turns soft, dark, or sunken — see the root rot page.
Plants on this site
These plant guides on this site already mention this problem: