Monstera Leaves Curling — What's Causing It and How to Fix It
Monstera (Monstera deliciosa)
Symptoms
- curling leaves
- leaves curling inward
- rolled leaves
- cupped leaves
- leaves curling under
- leaves curling up
- curling that begins at the leaf edges and works inward
- new leaf emerging already tightly curled
Causes
Underwatering / drought stress
When Monstera lacks sufficient water, leaves curl inward to reduce their surface area and slow transpiration. This is an active physiological response — the plant is trying to conserve moisture. Drought curling typically affects multiple leaves simultaneously and is accompanied by dry soil. Leaves may also feel thin or papery when squeezed gently, lacking normal turgidity.
Cold drafts or temperature shock
A sudden cold draft — from a door opened in winter, an air conditioning vent, or a leaf pressed against a cold windowpane overnight — can cause localized curling on the affected leaves specifically, while leaves elsewhere on the same plant remain flat and normal. This spatial pattern (only leaves nearest the cold source affected) is the clearest way to distinguish cold shock from a whole-plant issue like drought.
Low humidity
Even with adequate soil moisture, very low ambient humidity (below 30%) causes excessive water loss through the leaves' surface. The plant may curl leaves as a partial defense mechanism, though this is less pronounced in Monstera than in more humidity-sensitive aroids like Calathea. The key difference from drought curling: soil moisture is adequate, and the curling may be most pronounced on newer leaves or leaf tips.
Heat stress
Direct hot sun or proximity to heating vents can cause localized heat stress that manifests as leaf curling. The leaves physically curl away from the heat source. This is usually directional — only the side facing the heat curls, while the other side of the plant remains normal.
Root damage or overwatering
When root rot or overwatering has compromised the root system's ability to deliver water, leaves may curl despite the soil being moist. This is water stress from the delivery side rather than the supply side, and is a warning sign that root investigation is needed.
Thrips infestation
Thrips feed by puncturing leaf cells and consuming the contents. As they feed, the damaged cells die and contract, sometimes causing the leaf edges to curl or distort. Thrips damage is usually accompanied by silver streaking or stippling on the leaf surface.
Underlying nutrient deficiency, particularly potassium
Potassium plays a direct role in regulating how leaves manage water pressure at the cellular level, and a Monstera that's gone a long time without fertilizer, or is growing in nutrient-depleted soil that hasn't been refreshed in a year or more, can show leaf curling — usually starting at the margins — even when watering and humidity are both otherwise fine. This cause is easy to miss because it doesn't come with an obvious trigger like a missed watering or a cold draft.
How to Fix It
- 1
Check soil moisture first. Dry soil with curling leaves: water the plant thoroughly, ideally by bottom-watering. Wet soil with curling leaves: suspect root damage or pest activity.
- 2
Assess the environment: is the plant near a heat source or vent? Is the room particularly dry? Use a thermometer/hygrometer to check both temperature and humidity. Move the plant away from direct heat sources.
- 3
Inspect leaves carefully for pest signs — particularly look at the undersides for thrips damage (silver streaking, dark frass dots) or spider mites (fine webbing, stippling).
- 4
If root damage is suspected (soil wet, no pests, leaves still curling), unpot and inspect the root system as described in the root rot guide.
- 5
Once the primary cause is addressed, curled leaves on Monstera typically uncurl within hours to a couple of days if the damage is not permanent. Already-damaged tissue won't fully recover, but new leaves should emerge without curling once conditions improve.
- 6
If a specific leaf or two curled right after a cold event (an open door, a draft, an overnight cold snap near a window) while the rest of the plant looks fine, simply move the plant away from that specific cold source. These leaves typically relax back within a day or two once the temperature stabilizes, since the damage is usually mild and temporary rather than permanent cell death.
- 7
If none of the environmental or pest causes fit and the plant hasn't been fertilized in the current growing season, resume a balanced liquid fertilizer at half strength every four to six weeks during spring and summer. Improvement from a nutrient-related cause is gradual, visible over several weeks on new growth rather than an immediate change in existing leaves.
Prevention
- Test the mix with a finger rather than watering on autopilot, since Monstera's large fenestrated leaves curl visibly whether the plant is thirsty or sitting too wet
- Keep the plant away from heating vents and direct afternoon sun
- Maintain ambient humidity above 40% if possible
- Check leaf undersides and axils every couple of weeks so pests are caught before an infestation is large enough to trigger curling
- Ensure the root system is healthy by checking drainage and repotting periodically
- Keep the plant clear of drafty doorways, single-pane windows in winter, and direct air conditioning or heater airflow
- Fertilize on a regular seasonal schedule rather than letting the soil go a year or more without any nutrient replenishment
Normal vs. When to Worry
Normal: mild, brief curling on one or two leaves after an isolated cold draft or a single missed watering, which relaxes once the trigger is corrected. Worry: curling spreading across most of the plant, new leaves emerging already curled rather than opening flat, or curling paired with wet soil and no clear environmental trigger — these point to a root-level or pest cause that needs direct investigation rather than a simple environmental tweak.
Quick Summary
| Pattern | Likely Cause | Fix |
|---|---|---|
| Multiple leaves, dry soil | Underwatering/drought stress | Water thoroughly; bottom-water if very dry |
| Only leaves near a vent/window curling | Cold draft or temperature shock | Move away from the cold source |
| New leaves curl at tip, humidity low | Low humidity | Raise ambient humidity above 40% |
| Curling with wet soil | Root damage/overwatering | Check roots; treat root rot if present |
| Curling with silver streaking | Thrips | Treat with neem/spinosad; see thrips guide |
| Gradual curl at margins, no fertilizer in a year+ | Potassium/nutrient deficiency | Resume regular balanced fertilizing |