Monstera Root Rot: Signs, Treatment and Prevention

Overwatering is the leading cause of monstera root rot in the UK. In summer, a monstera in active growth may need watering every 7–10 days; in winter, every 3–4 weeks or less. The plant has no way to use excess water — it simply sits in the pot, displaces oxygen from the root zone, and creates perfect conditions for Pythium and Fusarium fungi to take hold. Multiple houseplant sources confirm that the first symptom of overwatering is yellowing of lower leaves, often confused with underwatering.

Stop it coming back:Use a moisture meter or the finger test before every watering rather than a fixed schedule. Monstera prefer to dry slightly between waterings — they are far more tolerant of underwatering than overwatering.

water your monstera on a rigid weekly schedule throughout winter — growth slows dramatically and the plant needs far less water than in summer.

Once overwatering has occurred, root rot develops rapidly. The main fungal pathogens — Pythium, Rhizoctonia, and Fusarium — are present in most composts and become active when soil is saturated and anaerobic. Healthy monstera roots are firm, white or pale tan. Rotting roots are black or dark brown, soft, mushy and may fall apart when handled. Epic Gardening notes that once roots are visibly rotting, they cannot be saved — only healthy root tissue can recover. However, a monstera with even a few surviving healthy roots can regenerate if treated promptly.

Stop it coming back:Early identification is the key to survival. Check the roots annually when the plant is repotted — pale, firm roots are healthy; dark soft roots need immediate action.

repot into the same old compost or pot — this re-inoculates healthy roots with the fungal pathogens that caused the rot in the first place.

Even correct watering frequency will cause root rot if the pot has no drainage holes, the drainage holes are blocked, or the compost is too dense and water-retentive. Standard heavy multipurpose compost used alone holds far too much water for monstera. UK houseplant retailer Patch Plants recommends adding perlite or orchid bark to create an open, free-draining mix. Decorative cache pots without drainage holes are a common hidden cause — the inner nursery pot sits in standing water inside the cache pot.

add a layer of gravel or stones to the bottom of the pot thinking it improves drainage — research shows this actually creates a perched water table that keeps roots wetter for longer.

Crown rot occurs when the rot extends from the roots up into the stem base — the growing crown of the plant. This is more serious than root rot alone, because the crown is the source of new growth. Soft, discoloured or mushy tissue at the soil line, or where the stem meets the compost, is the key sign. If the crown itself is fully rotted, the plant cannot be saved; if even a small section of firm, green stem above the rot remains, it may be possible to take a cutting and propagate a new plant.

leave crown rot untreated hoping the plant recovers on its own — once the stem base is compromised, the rot will continue to spread upward unless all affected tissue is removed.

Overwatered or root-stressed monsteras are more susceptible to secondary fungal and bacterial leaf infections. These appear as dark, water-soaked spots with yellow halos that expand over days or weeks. They are sometimes caused by splashing water onto leaves in warm conditions, poor airflow, or by fungal pathogens already active in wet compost. Leaf infections alone rarely kill a monstera but they indicate underlying stress that should be addressed.

Stop it coming back:Improve airflow and water only at the base. Monstera leaves are waxy and generally resistant to disease when the root system is healthy.

spray an overwatered monstera with a chemical fungicide on the leaves without first addressing drainage and watering — the leaf disease is a symptom; root stress is the cause.