Plant records · Bright indirect
Monstera deliciosa: light, water and why the leaves stop splitting
The split-leaf philodendron that is not a philodendron. Monstera deliciosa is forgiving about water and unforgiving about light: give it bright indirect exposure and it climbs; leave it in a dim corner and the new leaves come out solid, small and round.
Monstera deliciosa · Araceae
| Botanical name | Monstera deliciosaAraceae |
|---|---|
| Light | 1,000-2,500 lxBright indirect |
| Humidity | 50-70% |
| Watering | Every 9 days |
| Drainage | Chunky aroid mix: 40% orchid bark, 30% coco coir, 30% perlite. Refuses to sit in anything that holds a puddle at the bottom of the pot. |
| Mature height | 180 cm |
| Growth rate | Fast in summer, near zero from November to February. Expect 3-5 new leaves per warm season once the plant has a moss pole or trellis. |
| Propagation | Stem cutting with at least one node, rooted in water, sphagnum, or straight into the mother pot. Roots appear in 2-4 weeks at 22-26 C. |
| Pet safety | toxicInsoluble calcium oxalate crystals in leaf and stem sap. Chewing causes immediate mouth burning and drooling in cats and dogs; it is not usually fatal but is painful. |
presentationWhat you are seeing
- The most common complaint is a plant that grows steadily but stops producing fenestrated leaves. New growth comes out heart-shaped and solid, then hardens without ever splitting. The plant looks healthy, so it is easy to conclude nothing is wrong.
- The second complaint is a bare lower stem with four or five leaves crowded at the top of a leaning plant.
aetiologyWhy it happens
- Fenestration is a light-response, not an age milestone. Juvenile Monstera leaves are always solid. Splitting and inner holes appear once the plant is receiving roughly 1,000 lx or more for most of the day and has something to climb. A plant kept at 300-400 lx will stay juvenile indefinitely no matter how old it is.
- A bare lower stem is normal maturation: the plant abandons old leaves as it climbs. It is not a sign of a nutrient problem, and feeding it harder will not regrow leaves on a leafless stretch of stem.
managementWhat to do
- Move the plant to within 1-1.5 m of an east or south window, or 0.5 m back from a west window, screened by a sheer curtain. Aim for 1,000-2,500 lx measured at leaf height with a phone lux meter at midday.
- Add a moss pole or a coir totem and tie the main stem to it with soft twine. Aerial roots that find the pole will thicken the stem and trigger larger leaves.
- Water when the top 3-4 cm of mix is dry. In a chunky aroid mix at 22-24 C that is roughly every 9 days in summer and every 14-18 days in winter.
- Wipe dust off the leaves every 3-4 weeks. Dust at the density that builds up on a large Monstera can cut the light reaching the leaf by a noticeable margin.
- Do not repot into a much larger container to 'encourage growth'. A pot more than 5 cm wider than the root ball keeps the mix wet too long and stalls the plant.
Reading the light in a real room
Monstera is often sold as a low-light plant because it survives in a dim room. Surviving and sizing up are different things. In a north-facing room 2 m back from the glass, a phone lux meter typically reads 150-300 lx at midday; the plant will hold its existing leaves for a year or more and produce almost nothing new.
The useful test is not the room, it is the spot. Take a reading at the height of the topmost leaf at midday in summer. Below 500 lx the plant is in maintenance mode. Between 1,000 and 2,500 lx it grows and fenestrates. Above 3,500 lx of unfiltered midday sun in summer, the leaves will scorch along the midrib.
- North window, 0.5 m back: 200-400 lx — maintenance only
- East window, 1 m back: 800-1,500 lx — good
- South window, 1.5 m back behind a sheer: 1,500-2,500 lx — ideal
- West window, 0.5 m back: 2,000-3,000 lx — good, watch summer afternoons
- Grow light at 30 cm, 12 h/day: 2,000-4,000 lx — the most controllable option
Watering by weight, not by calendar
The every-9-days figure is a starting point for a 20 cm pot in summer, not a rule. The reliable method is to lift the pot. A well-watered 20 cm Monstera in chunky mix feels heavy and solid; a dry one is noticeably light and the mix sounds hollow if you tap the side.
Yellow lower leaves with soft, limp tissue usually mean overwatering. Yellow lower leaves that are dry and crisp at the edge usually mean the plant is root-bound and the mix is drying out faster than you are watering. Same colour, opposite cause.
Fertiliser and the salt problem
Feed at half strength every third watering from March to September. A balanced 3-1-2 liquid feed at 1 ml per litre is plenty. Monstera is not a heavy feeder and over-fertilising produces long petioles with small blades, which reads as leggy growth rather than vigorous growth.
If a white crust forms on the surface of the mix or around the rim of the pot, that is accumulated fertiliser salt. Flush the pot with room-temperature water at roughly three times the pot volume, let it drain completely, and skip feeding for six weeks.
Troubleshooting
Why are the new leaves smaller than the old ones?
Can I keep it in a bathroom with no window?
The aerial roots are long and messy. Can I cut them?
CaveatCare information only. The plant is toxic to cats, dogs and small children if chewed — contact a veterinarian or poison control centre rather than treating this page as veterinary advice.
Published2026-08-18 ·