Brown spots are dead or injured tissue, but the color does not reveal the cause. Sunburn, cold, chemical spray, edema, pests, fungal or bacterial disease, mechanical damage, salts, and root stress can all produce brown areas.
Diagnose the pattern and progression before spraying or changing the watering routine.
Six questions that narrow the cause
- Where did the spot begin: tip, edge, center, underside, or new growth?
- Is it dry, crisp, soft, water-soaked, raised, or sunken?
- Is there a yellow halo, concentric ring, ooze, webbing, or pest?
- Is the damage on one exposed side or scattered through the plant?
- Are new spots appearing or is the damage stable?
- What changed before it appeared: light, cold, spray, fertilizer, watering, or repotting?
Pattern guide
| Pattern | Strong possibilities | Decisive check |
|---|---|---|
| Bleached tan patch on window-facing side | Sudden sun or heat injury | Recent move; damage aligns with exposure |
| Dry brown tips and margins | Moisture stress, salts, low humidity, heat | Root-zone pattern and white crust |
| Water-soaked spot with yellow halo | Bacterial or fungal disease possible | Expansion, ooze, wet foliage, plant-clinic diagnosis |
| Corky raised bump under leaf | Edema | No pest; wet conditions; blister progression |
| Fine pale specks becoming bronze | Spider mites | Mites/webbing under leaf, white-paper test |
| Soft dark spot at stem base | Crown or stem rot | Firmness and root inspection |
| Single torn or creased patch | Mechanical injury | Stable shape at contact point |
UC IPM lists excess light, chilling, chemical injury, overwatering, and fungal or bacterial infections among causes of leaf spots. Clemson Extension notes that fungal spots may have yellow margins or target patterns, while bacterial spots may begin water-soaked and sometimes ooze.
Sunburn and heat damage
Sunburn often follows a move to stronger light and affects the exposed side. Tissue may bleach first, then become tan or brown and crisp. The boundary can be sharp where another leaf shaded part of the surface.
Move the plant back from intense exposure and acclimate gradually. Damaged tissue will not recover, but new growth should remain clean.
Watering and root stress
Brown tips can occur in both excessively dry and excessively wet systems. Dry roots cannot supply water; damaged roots in wet soil also cannot supply water. Check the root ball and drainage before deciding.
If the plant wilts in wet mix or has soft roots, follow the root rot guide. If the pot is very light and the mix has pulled from the sides, rehydrate the root profile and revise the checking routine.
Salt and fertilizer injury
White or tan crystalline crust on soil, pot rims, or drainage holes suggests soluble salts. Salts can injure root tips and cause marginal or tip burn. Reduce unnecessary fertilizer, avoid softened water, and leach only through a freely draining container.
Pest damage
Inspect both leaf surfaces with magnification. Spider mites cause fine stippling and possible webbing. Thrips often leave silvery scarring and dark fecal specks. Scale insects can resemble bumps but may scrape away from the leaf surface.
Treat only after confirming the pest. See the spider mite protocol when stippling and mites are present.
Fungal or bacterial leaf spots
Potential warning signs include spots that expand under wet conditions, water-soaked margins, strong yellow halos, concentric rings, visible spores, or sticky ooze. Isolate the plant, avoid splashing foliage, remove heavily affected material with clean tools, and improve spacing.
Do not diagnose a pathogen by photograph alone when the result would trigger pesticide use. A plant clinic may need living tissue from the advancing edge.
Edema
Edema produces blister-like or corky raised spots, usually under leaves, when root water uptake outpaces transpiration. It is not contagious. Use the complete edema guide to compare it with mites and disease.
Should you remove spotted leaves?
Remove a leaf when it is mostly dead, actively diseased, or prevents monitoring. Keep a partly green, stable leaf when the plant needs its photosynthetic area. Sterilize tools between suspicious plants and dispose of diseased material.
Frequently asked questions
Will a brown spot heal?
No. Dead tissue remains scarred. Success means the spot stops expanding and new growth is healthy.
Are brown spots always fungal?
No. Environmental and care causes are common indoors, and pests, salts, cold, sun, edema, and mechanical damage can look similar.
Should I spray neem oil on brown spots?
Not unless a labeled target pest is confirmed. Oil does not repair dead tissue and can cause additional injury on a stressed or light-exposed plant.
What photo should I take for diagnosis?
Capture the whole plant, both sides of the affected leaf, the pot and soil, and a close view of the advancing edge. Include an unaffected leaf for comparison.
The spot rule
Location, texture, halo, spread, and history matter more than brown color. Identify the pattern, inspect roots and pests, and treat only the cause that the evidence supports.
Plant-Specific Brown-Spot Guides
Compare the general spot pattern with the reviewed guides for Calathea brown spots and fiddle leaf fig brown spots.