Why Is Your Monstera Turning Brown & How to Fix it

A monstera with brown leaves is almost always responding to one of eight conditions: sunburn, underwatering, overwatering and root rot, low humidity or tap water minerals, overfeeding, bacterial or fungal leaf disease, pests, or the natural ageing of older leaves.

Most of these are straightforward to fix once correctly identified.

Bacterial leaf spot is the cause most guides skim past, because it is frequently mistaken for ordinary fungal leaf spot or drought damage until it has already spread to several leaves.

Distinguishing it early, and understanding why it needs a different response, is one of the most useful things this guide can give you.

This guide works through every major cause with the diagnostic detail needed to identify which one you are dealing with, since treating the wrong cause rarely helps and can occasionally make things worse.

Monstera deliciosa, the Swiss cheese plant, is prized for its dramatic split leaves and its reputation as one of the easier large houseplants to keep.

That reputation is generally earned, but brown leaves are one of the most common complaints from monstera owners, and the frustrating part is that several very different problems produce almost identical brown patches.

A brown patch caused by sunburn needs the opposite response to a brown patch caused by underwatering, and a brown, foul-smelling stem base needs urgent action rather than a wait-and-see approach.

The pattern, location, and speed of the browning matter far more than the colour itself.

How to Diagnose What Is Wrong: Reading the Symptoms

Before working through each cause individually, it helps to read the pattern of the damage rather than just the colour, because several causes produce brown leaves that look superficially similar at first glance.

1. Sunburn and Excess Light

Sunburn is one of the two most common causes of monstera leaves turning brown, and it is frequently confused with heat stress or simple ageing because both can leave a leaf looking scorched.

The distinguishing detail is location. Sunburn concentrates on the leaves and the side of the leaf facing the light source, since it is the direct radiant heat and intensity of the light hitting the leaf tissue that causes the damage, not the ambient temperature of the room.

A leaf scorched on one side while the other side stays green is a reliable sign of sunburn rather than heat stress or general decline.

Monstera evolved as an understorey plant beneath a forest canopy in its native range, receiving filtered, dappled light rather than direct sun.

Direct sun magnifies through the water in the leaf tissue in a way the plant has no natural tolerance for, and the chlorophyll in the affected cells breaks down, leaving a dry, bleached, or dark brown patch that cannot green up again.

Early sunburn often shows as pale, washed-out, or grey patches before the tissue actually browns, so catching it at this stage and moving the plant limits how much damage spreads.

Fixing it

Move the plant back from direct sun, aiming for bright indirect light such as a spot a few feet back from a south or west-facing window, or directly in front of an east-facing one.

See our full guide to monstera light requirements for how to judge what “bright indirect” actually looks like in a UK home.

Move the plant gradually if you are relocating it a significant distance, since a plant that has adapted to lower light can scorch even in indirect light if the jump in intensity is sudden.

If the position is otherwise correct but summer sun is more intense than in winter, a sheer curtain or blind to diffuse the light is often enough rather than moving the plant entirely.

For a plant that already has significant sunburn damage, our dedicated guide on how to save a monstera with sunburn covers the recovery timeline and what to expect from new growth in more detail than we can here.

2. Underwatering and Drought Stress

Underwatering produces a fairly predictable progression that helps distinguish it from both overwatering and humidity-related browning.

Leaves droop and feel thin or papery first, and the soil visibly pulls away from the sides of the pot.

At this stage, the plant recovers within a day or two of a thorough watering, without any lasting brown damage.

If drought stress continues, yellowing follows as the plant sheds older leaves to conserve resources, and in more severe or prolonged cases the leaf edges and tips brown and crisp without an initial yellowing phase.

The confirming test is simple: press a finger 5cm (2in) into the soil.

If it comes out dry and the soil has pulled away from the pot’s inner edge, underwatering is confirmed, and no smell will be present, which is the key thing separating this from root rot below.

Fixing it

Water thoroughly until it runs freely from the drainage holes, let the pot drain fully, and do not let it sit in standing water afterwards.

If the soil has dried to the point of becoming hydrophobic and repelling water, stand the pot in a few centimetres of room-temperature water for 20 to 30 minutes so the compost rehydrates evenly, then let it drain completely.

Going forward, base watering on how the soil actually feels rather than a fixed calendar. Our full monstera watering schedule guide covers how this should adjust across the seasons in a UK home.

3. Overwatering and Root Rot

Overwatering is the other most common cause of monstera decline, and it is the cause most frequently confused with underwatering, since both eventually produce yellowing and browning leaves.

The distinguishing detail is the soil itself, not the leaves.

Overwatered soil feels consistently wet or soggy several inches down, and where root rot has taken hold there is often a distinctly sour or swampy smell from the base of the pot, something drought stress never produces.

When a monstera sits in waterlogged soil, the roots are starved of oxygen, root cells begin to die, and the resulting anaerobic conditions allow fungal pathogens to establish and rot the remaining root tissue.

A plant with a compromised root system cannot take up water or nutrients, which is why the visible symptoms look deceptively like drought stress even though the soil is sodden.

The gentle tug test

Grip the base of the main stem where it meets the soil and give it a very slight upward pull, no more force than lifting a teacup.

A healthy monstera feels anchored; a loose or shifting plant suggests the root system has been compromised and it is worth unpotting to check.

Fixing it

If confirmed, ease the plant from its pot, trim away any soft, brown, or black roots back to firm, pale tissue using clean scissors, wiping the blades with rubbing alcohol between cuts, then repot into fresh, well-draining aroid mix.

Hold off on a full watering until the top 5 to 8cm (2 to 3in) of soil has dried out.

Our dedicated guide on how to fix root rot in a monstera walks through this process in full step-by-step detail, including what to do if the damage has reached the lower stem.

4. Low Humidity and Tap Water Minerals

Brown, crispy tips are usually blamed entirely on low humidity, but there are two other common causes worth ruling out first, and the confusion between them is one of the most common misdiagnoses in monstera care.

Low humidity produces gradually browning tips that start papery and dry, typically worse in winter when central heating is running.

Tap water mineral buildup, from the fluoride, chlorine, or dissolved salts present in most mains water, produces a similar dry, brown tip, but tends to appear regardless of season and often comes with a faint white crust on the soil surface where the minerals have accumulated.

The distinguishing test is straightforward. Switch to filtered, distilled, or rainwater for three to four waterings.

If new leaves stop developing brown tips while humidity and everything else stays the same, water quality was the more significant factor rather than the air itself.

Monsteras are tropical understorey plants and, per the RHS growing guide for Swiss cheese plants, do best kept at 18 to 25°C (65 to 77°F) with moderate humidity, which is straightforward to replicate in most UK homes by grouping plants together, using a pebble tray, or running a small humidifier nearby.

Our guides on misting a monstera for humidity and the ideal humidity for a monstera cover the practical setup for both approaches in more depth.

5. Overfeeding and Fertiliser Burn

Monsteras are moderate feeders, and their roots are sensitive to the concentrated salts in synthetic fertiliser when it is applied too often or at too strong a dose.

The result of overfeeding is not lush growth but nutrient burn: concentrated salts in the soil draw moisture out of the fine root hairs through osmosis, producing the same browning and crisping symptoms as drought stress even when the soil is adequately moist.

This is what makes fertiliser burn easy to mistake for underwatering, since the leaves look the same even though the cause and the fix are opposite.

A white or crusty deposit on the soil surface or around the drainage holes is the clearest visual indicator separating fertiliser burn from drought, since dry soil alone does not leave this residue.

Fixing it

Flush the soil thoroughly by watering until it runs freely from the drainage holes several times in succession, allowing full drainage between passes, then withhold all fertiliser for four to eight weeks.

Resume at half strength once new, healthy growth appears. Our guide to choosing a fertiliser for your monstera covers the right feeding schedule to avoid this happening again.

6. Bacterial and Fungal Leaf Disease: The Cause Most Guides Skip Past

This section deserves more space than most monstera guides give it, because bacterial and fungal leaf disease is genuinely common and is very easy to mistake for ordinary environmental browning until it has already spread across several leaves.

Anthracnose

Anthracnose is a fungal disease, most often caused by Colletotrichum species, and it produces a distinctive progression: the leaf tips or margins yellow first, then darken through tan to dark brown, with the browning gradually spreading around the whole leaf rather than staying confined to one patch.

Left untreated, affected leaves eventually die and drop.

The key distinguishing feature from sunburn or humidity damage is that anthracnose spreads across the whole leaf over days rather than staying static at the point of initial damage, and it is worse in humid, still air with wet foliage, since the fungus depends on moisture on the leaf surface to spread from spores.

Treatment is to remove and destroy infected leaves with sterilised scissors, stop misting or wetting the foliage directly, and improve air circulation around the plant.

Established infections can be treated with a copper-based fungicide spray, applied after infected material has been removed.

Bacterial leaf spot

Caused by Pseudomonas or Xanthomonas bacteria, this shows up as small, water-soaked spots that are often angular in shape, bounded by the leaf veins rather than spreading in an even circle, and typically surrounded by a yellow halo before the centre browns.

The angular, vein-bounded shape is the clearest distinguishing feature from anthracnose and other fungal leaf spots, which tend to spread in rounder, less geometric patches.

Bacterial leaf spot spreads through water splashing between leaves, so overhead watering and misting directly onto foliage both increase risk.

Remove affected leaves, stop wetting the foliage when watering, and increase air circulation.

A copper-based bactericide can help contain an active outbreak, though drier foliage matters more than any spray.

7. Pests

Weakened or stressed monsteras are more vulnerable to pests, and an infestation can itself be the underlying reason for browning rather than a secondary nuisance.

Spider mites produce fine webbing and a stippled, bronzed appearance before leaves brown outright, and are especially common in the dry air conditions created by central heating.

Thrips leave silvery, papery patches with small black dots of excrement, distinguishable from sunburn by their scattered, speckled pattern rather than a single scorched zone.

Mealybugs and scale both produce sticky honeydew residue alongside small, visible white or brown clusters at leaf junctions.

Check leaf undersides and stem junctions with a torch or phone light. Isolate the affected plant immediately, wipe leaves down with a damp cloth or diluted insecticidal soap, and repeat every 7 to 10 days for several cycles.

Our guides to the most common monstera pests and how to get rid of thrips on a monstera cover identification and treatment for each pest in full detail.

8. Natural Ageing

Not every brown leaf signals a problem. Monstera leaves have a natural lifespan, and the oldest, lowest leaves on the plant will eventually yellow and brown even on a perfectly healthy plant, usually one leaf at a time and only occasionally.

The distinguishing feature from disease or stress is that this affects only the very oldest leaves at the base of the plant, happens slowly over weeks, and is not accompanied by any soil odour, pest sign, or spreading pattern across newer growth.

If only one old leaf is affected and the rest of the plant looks vigorous with new growth appearing, this is normal turnover rather than a symptom to treat.

Quick Diagnostic Reference

Frequently Asked Questions

Why is my monstera turning brown?

The most common reasons are sunburn from too much direct light, underwatering, overwatering and root rot, low humidity or tap water minerals, overfeeding, or bacterial and fungal leaf disease.

The pattern of the browning is the most useful diagnostic detail: a patch on the side of the leaf facing a window points to sunburn, a gradual crisping of just the tips points to humidity or water quality, and dark, soggy, sour-smelling soil points to root rot.

Identifying the specific pattern before treating avoids wasting time on the wrong fix.

Can brown monstera leaves turn green again?

No. Once leaf tissue has browned, the chlorophyll and cell structure in that section has broken down and it cannot recover its green colour.

The plant itself can fully recover once the underlying cause is fixed, and new growth will be healthy, but the already-browned tissue on existing leaves will not reverse.

Trimming off the brown portion, or the whole leaf if most of it is affected, is the right approach rather than waiting for it to green back up.

Should I cut off brown monstera leaves?

Yes, though how much depends on how much of each leaf is affected.

If only the tips or edges are brown, trim just the dead portion with clean, sharp scissors, following the natural shape of the leaf as closely as possible, since this stops the plant expending energy on tissue that cannot recover.

If most of a leaf is brown, remove the whole leaf close to the stem.

Avoid removing more than one or two leaves at a time even if several are affected, since cutting too much at once reduces the plant’s capacity for photosynthesis and can slow its recovery.

Our guide to pruning a monstera covers the correct technique in more detail.

How do I tell the difference between sunburn and bacterial leaf spot?

Location and shape are the key distinctions. Sunburn produces a scorched patch concentrated on the leaves and the side of the leaf facing the light source, and it stays static once it appears rather than spreading further.

Bacterial leaf spot produces smaller, angular spots bounded by the leaf veins, usually with a yellow halo, and these spots continue to appear on new leaves and spread if the underlying moisture conditions are not corrected.

A single static scorch mark is very unlikely to be bacterial; multiple, spreading, angular spots across several leaves point away from sunburn.

Why does my monstera have brown spots but the rest of the plant looks healthy?

Isolated brown spots on an otherwise healthy plant are most often either bacterial leaf spot, in its early stages, or physical damage from a knock, insect bite, or accidental abrasion that has scarred over.

Check whether the spots are angular and vein-bounded, which suggests bacterial leaf spot, or irregular and centred on a single point of visible damage, which suggests a physical cause that is not contagious and does not need treatment beyond trimming the affected area if it bothers you visually.

Is it normal for old monstera leaves to turn brown?

Yes. The oldest, lowest leaves on a monstera naturally yellow and brown over time as the plant redirects resources to new growth, and this is completely normal provided it only affects one leaf at a time, happens slowly, and the rest of the plant continues producing healthy new leaves.

It becomes worth investigating further only if several leaves brown at once, if newer growth is affected, or if the browning is accompanied by a soil odour or visible pests.

How often should I water a monstera to prevent brown leaves?

Check the soil rather than following a fixed schedule. Water again once the top 5 to 8cm (2 to 3in) has dried out, which is often every 10 to 14 days indoors in the UK, though this varies with light, pot size, and the season, typically lengthening over autumn and winter as growth slows.

Both consistently overwatering and consistently underwatering will eventually produce brown leaves, so matching the schedule to how quickly the specific plant’s soil actually dries is more reliable than any fixed interval.

Key Takeaways

1. Read the pattern and location before treating. A static scorch mark facing a window is sunburn. Spreading, angular spots are bacterial leaf spot. Dark, sour-smelling soil is root rot. Each needs a different fix.
2. Brown tissue will not turn green again. Once a leaf has browned, focus on stopping the spread and protecting new growth rather than expecting the existing damage to reverse.
3. Check the soil before assuming humidity or water quality. Both overwatering and underwatering can produce browning that looks similar to environmental causes at first glance.
4. Fertiliser burn mimics drought stress. A white crust on the soil surface is the tell that separates the two, since both produce similar-looking crispy, browning leaves.
5. Bacterial leaf spot and anthracnose both spread if untreated. Isolated damage that stays static is unlikely to be disease; spreading, multiplying spots need leaves removed and airflow improved.
6. Sunburn concentrates on the side of the leaf facing the light. This is the clearest way to distinguish it from heat stress or general decline, which affect the whole plant more evenly.
7. One old, lower leaf browning slowly is normal ageing, not a sign of a problem, provided the rest of the plant looks vigorous.
8. Don’t feed a stressed or recovering plant until new growth appears, and resume at half strength once you do.
9. Only trim one or two leaves at a time even if several are affected, since removing too much foliage at once slows the plant’s overall recovery.

Final Thoughts

Most monstera browning comes down to a small number of environmental basics: consistent watering based on how the soil actually feels, bright but indirect light, moderate humidity, and a fertilising routine that matches the season rather than a fixed calendar.

The difficulty is rarely in fixing any one of these once identified. It is in correctly telling them apart in the first place, since sunburn, drought, overfeeding, and bacterial disease can all leave a monstera leaf looking brown and crisp within a day or two of each other.

Taking thirty seconds to check the soil, look at where on the plant the damage is concentrated, and note whether it is spreading or static almost always narrows the cause down to one or two candidates before you need to change anything.