Short answer
Monstera deliciosa typically develops root rot due to overly frequent watering or poor drainage that leaves roots sitting in stagnant moisture. The most effective fix is to remove the plant from its pot, trim away all mushy, dark-colored roots, and repot it into fresh, well-draining aroid soil mix.
Root rot in Monstera deliciosa often presents as generalized yellowing, drooping, or blackening of the lower foliage, despite the soil surface feeling damp. While this condition is serious because it compromises the plant's ability to take up water, it is often reversible if identified before the crown of the plant turns to mush.
Monstera deliciosa are epiphytic by nature and require a strict cycle of drying out between waterings. If you water on a fixed schedule regardless of whether the top two inches of soil are dry, the root system remains constantly saturated, leading to anaerobic conditions that promote fungal rot.
Check: Dig two inches deep into the soil; if it is still wet or smells sour/musty, overwatering is confirmed.
Fix: Adjust your watering routine to strictly follow the 'dry top two inches' rule, and consider switching to an aroid mix containing bark, perlite, and peat for better aeration.
Even with proper watering intervals, a heavy, dense soil mix or a pot without functional drainage holes will trap water at the bottom. This creates a 'bathtub effect' where the lower roots are submerged in standing water, even if the topsoil appears dry.
Check: Check the bottom of the pot to ensure water flows freely; if there is no drainage hole or the soil is packed solid like mud, the container and medium are likely the issue.
Fix: Repot the plant into a container with drainage holes and use a chunky, breathable substrate that allows oxygen to reach the roots.
Placing a Monstera in a pot that is too large for its root system results in vast areas of unused soil that remain moist for far too long. This excess moisture has nowhere to go, preventing the roots from drinking it all before it begins to decay.
Check: Carefully slide the plant out of its pot; if you see a small, tight root ball surrounded by a large mass of damp, unused soil, the pot is too big.
Fix: Downsize to a pot that is only 1-2 inches wider than the current root ball to ensure the soil can dry out at a reasonable pace.
When to worry
You must act immediately if the stems become squishy near the base or if the yellowing rapidly progresses to the newest, unfurled leaves, as this indicates systemic rot that may be irreversible.
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Diagnose my MonsteraNo, removing yellow leaves only hides the symptoms and does not treat the rotting root system below the soil. You must address the health of the roots to stop the decline.
A diluted hydrogen peroxide soak can help disinfect healthy roots after trimming, but it is not a replacement for repotting into fresh, airy soil.
If your soil remains wet for more than two weeks, it is likely too dense, or the plant is in a location with insufficient light to drive transpiration. Increase the light exposure and replace the soil with a mixture containing more perlite or orchid bark.
Consistent with guidance from: Royal Horticultural Society Plant Care Guides, University of Florida IFAS Extension: Monstera deliciosa Fact Sheet.