Why does my monstera have brown spots?
Brown spots on a monstera can have more than one cause. Leaf spot disease is one, and Iowa State University Extension and Outreach links it to wet leaves, poor airflow and crowding. Look at the color, edge and pattern of the spots. Then check the roots and the leaf surface.
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What do monstera brown spots look like?
Monstera brown spots can come from a fungal or bacterial leaf spot. The pattern helps you tell them apart. Iowa State University Extension and Outreach says disease is often a secondary problem, caused by poor conditions or care.
- Fungal spots: Clemson Cooperative Extension describes small brown spots with yellowish edges, sometimes in a ring or target pattern. UC Statewide IPM Program says they often run from tan to reddish brown to black. They are roughly circular and can merge into large, uneven patches.
- Bacterial spots: UConn Home and Garden Education Center describes dark brown spots with a yellow border, similar in size, often with a sticky ooze. UC Statewide IPM Program says they start as dark green, water-soaked spots. They can grow until the whole leaf blade is affected.
- Spots that grow with age: Iowa State says leaf spot can form rings with dark, dead centers. The spots grow with age and can eventually cover the whole leaf.
- Powdery mildew: Clemson says it can cause white, powdery growth or dry, brown, papery spots.
- Dry conditions: Clemson says that in drier conditions, bacterial spots may stop growing, dry out and turn reddish brown. This gives a speckled look.
How can I tell what’s causing the spots?
Monstera brown spots have more than one possible cause, so look at the spot and the whole plant together. The Royal Horticultural Society says a correct diagnosis often depends on what other signs of ill-health are present.
| What you notice | What to check | A useful next step |
|---|---|---|
| Dark spots with a yellow border, maybe sticky ooze | Bacterial leaf spot. Check for cold, crowding and wet leaves. | Remove affected leaves and keep the foliage dry. |
| Small brown spots with target rings | Fungal leaf spot. Check for wet leaves and poor airflow. | Remove infected leaves and avoid splashing water on the foliage. |
| White or straw-colored spots or rings | Cold water splashes, aerosol products, or too much sun. | Use room-temperature water, skip aerosols, and move the plant out of a bright window. |
| Browning in the middle of leaves | Overwatering often causes this. Check the roots. | Tip the plant out of its pot and look at the roots. |
| Sticky residue on the leaves | Mealybugs, which can leave a sticky residue. | Wipe the leaves, which can remove insects and dust. |
What should I do first about leaf spot disease?
Start with the gentlest steps. Remove the infected leaves, keep the foliage dry and give the plant room. Clemson Cooperative Extension says to remove infected plant material and provide good air circulation.
- Remove affected leaves. UC Statewide IPM Program says managing bacterial leaf spots generally includes prompt removal of infested parts. It says to wash your hands with soap and water after that, and to disinfect pruning tools with alcohol. Iowa State adds that clean soil, containers and tools help prevent disease.
- Keep leaves dry. UC Statewide IPM Program says fungal leaf spots can usually be prevented by not splashing water on foliage. It also says to water early in the day, so the leaves dry as quickly as possible. Iowa State links leaf spot to wet leaves, usually from misting or watering.
- Improve airflow and conditions. Iowa State says spacing plants apart gives better air circulation. For bacterial leaf spot, UConn says to avoid low temperatures and crowding, and to increase airflow to reduce humidity.
- Be careful with chemicals. UConn says chemicals are not recommended for bacterial leaf spot. Iowa State says most fungicides prevent the spread of disease but do not cure current infections. If you do consider a product, follow the product label and use one labeled for houseplants.
Iowa State also says most disease problems can’t be cured, only prevented. If the problem is big, the plant is not likely to recover. For a severe case, ask a local nursery or your extension service.
Could watering, light or pests be involved?
They can be. Care problems can start the damage, and disease often follows. Iowa State says several factors often contribute. It says to correct all of them while you focus on the primary cause.
- Watering: UConn says to let the top 2-3 inches of soil dry between waterings. If you aren’t sure the soil is dry, learn how to tell if a plant needs water. The Royal Horticultural Society says a pot left in a saucer of water can cause the roots to rot.
- Roots: The Royal Horticultural Society says to tip the plant out of its pot and check the roots. UC Statewide IPM Program says healthy roots should be white. Brownish to blackish roots often mean root rot. See the guide on root rot if the roots look bad.
- Light: The Royal Horticultural Society says pale spots may develop if a plant gets too much sun.
- Pests: University of Wisconsin-Madison Extension says monstera has few indoor pests. Aphids, mealybugs, scale insects or spider mites may infest it. Look for signs of these pests, including mealybugs and scale insects.
- Bruising: The Royal Horticultural Society notes that passing pets and people can bruise leaves.
When should I get a second opinion on the spots?
A second look helps when the spots match none of the patterns above. It also helps when they keep spreading after you change the care. Take clear photos of the front and back of a leaf. See how to photograph a sick plant for the best angles.
Plant Doctor, an AI plant diagnosis app for iPhone, reads three photos and names the most likely cause along with the evidence behind it.
Monstera questions
Should I cut off monstera leaves with brown spots?
Often, yes, when the spots look like disease. Clemson Cooperative Extension says to remove infected plant material. UC Statewide IPM Program says to do it as soon as symptoms appear. Clean your hands and tools afterward.
Can a monstera recover from leaf spot disease?
It depends on how big the problem is. Iowa State University Extension and Outreach says most disease problems can’t be cured, only prevented. A plant with a big problem is not likely to recover.
Does misting cause brown spots on a monstera?
It can, if the leaves stay wet. Iowa State links leaf spot to wet leaves, usually from misting or watering. UC Statewide IPM Program says managing bacterial leaf spots generally means lowering humidity and keeping plant surfaces dry.
Sources and further reading
Care guidance checked against the sources below. Plant Doctor’s app examples are separate from these references; the institutions do not endorse the app.
- UConn Home and Garden Education Center — Monstera deliciosa | Home Garden Education Office | College of Agriculture, Health and Natural Resources | University of Connecticut
- University of Wisconsin-Madison Extension — Swiss-Cheese Plant, Monstera deliciosa
- Royal Horticultural Society — How to grow Swiss cheese plants
- Royal Horticultural Society — Leaf damage on houseplants
- Clemson Cooperative Extension — Houseplant Diseases & Disorders
- Iowa State University Extension and Outreach — Diagnosing Houseplant Problems from Diseases
- UC Statewide IPM Program — Houseplant Problems
Drafted with AI from the sources below; each plant-specific fact checked automatically against its source on 24 October 2026.
This guide offers general plant-care information. A photo cannot confirm every cause; a local nursery or extension service can help with severe or unclear cases.