The splits and holes in a monstera leaf — the fenestrations that give Monstera deliciosa its nickname, the Swiss cheese plant — are the whole reason most people buy one. So it’s frustrating when leaf after leaf unfurls smooth, solid, and heart-shaped with no holes at all. The reassuring news is that a monstera without fenestrations is almost never sick. It’s usually just young, under-lit, or lacking something it needs to start splitting. This guide explains the four reasons a monstera fails to fenestrate, how to tell which one is holding yours back, and what to change so the next leaves come in fully slotted.
Key Takeaways
- Young monsteras don’t fenestrate — most plants need to reach 2 to 3 years old before leaves split.
- Insufficient light is the most common fixable cause; monsteras need bright, indirect light to develop holes.
- A climbing pole or moss support triggers larger, more fenestrated mature leaves.
- Weak or undersized new leaves often signal a nutrient shortfall — feed through the growing season.
- Each new leaf should be bigger and more split than the last; if leaves are shrinking, something is wrong.
Cause 1: The plant is simply too young
This is the single most common reason, and it’s not a problem at all — it’s biology. Monsteras produce solid, heart-shaped juvenile leaves first. Fenestration is a sign of maturity, and the plant only begins splitting its leaves once it has built up enough size and energy reserves. Depending on conditions, that’s typically around 2 to 3 years of age. A small monstera you bought at a nursery with two or three solid leaves is just a baby; expecting holes from it is like expecting fruit from a year-old apple tree.
How to diagnose it
Count the leaves and look at their size. If your plant has only a handful of small leaves (under about 8 inches across) and a slim stem, it’s almost certainly immature. The first fenestrations often appear as small notches along the leaf edge before they develop into the dramatic interior holes of a mature plant. If you’re seeing those edge notches starting, the plant is right on schedule.
How to fix it
Patience plus good care. You can’t force a juvenile plant to mature faster than its growth allows, but you can speed it up by giving it the best possible conditions — bright indirect light, consistent watering, a support to climb, and regular feeding in the growing season. Each new leaf should emerge larger than the one before it. Once leaves push past roughly 10 to 12 inches wide, fenestrations usually follow. Keep the plant growing steadily and the holes will come.
Cause 2: Not enough light
If your monstera is past the juvenile stage but still pushing out solid leaves, light is the most likely bottleneck. Fenestration is energy-expensive — the plant needs to photosynthesize enough to justify building large, elaborate leaves. In the wild, monsteras climb toward the bright canopy, and the holes are thought to help leaves withstand wind and let light filter down to lower foliage. In a dim living room, the plant simply can’t gather enough energy to make split leaves, so it defaults to small, solid ones.
How to diagnose it
Look for stretching and small leaves. A light-starved monstera produces long gaps between leaves (leggy growth), reaches toward the nearest window, and makes new leaves that are smaller than older ones — the opposite of healthy progression. If the plant sits more than 6 to 8 feet from a window or in a north-facing room with no supplemental light, it’s likely under-lit.
How to fix it
Move the plant to bright, indirect light — a few feet back from an east or west window is ideal, or right beside a north window. Monsteras can take a little gentle morning sun, but harsh midday direct sun scorches the leaves, so filter strong light with a sheer curtain. If your home is genuinely dark, add an LED grow light running 10 to 12 hours a day positioned 12 to 18 inches above the plant. Give it a few months of brighter light and watch the next few leaves — they should come in larger and start to slot. Rotate the pot weekly for even growth.
Cause 3: No support to climb
Monstera deliciosa is a climber. In its native habitat it scrambles up tree trunks, and that vertical growth habit is tied to leaf maturation. When a monstera climbs, it sends out aerial roots that grip the support, and the plant responds by producing larger, more fenestrated leaves. Left to sprawl across a tabletop or flop over the side of a pot, a monstera often stays stuck in a more juvenile growth pattern with smaller, less-split leaves.
How to diagnose it
Is your monstera trailing sideways or drooping rather than growing up? Are the aerial roots dangling without anything to attach to? A plant that’s been left to sprawl, especially one that’s otherwise well-lit and mature in age, is a strong candidate for the no-support diagnosis.
How to fix it
Add a moss pole, coir pole, or sturdy stake and train the plant upward. Tie the main stem loosely to the support with soft plant ties or twine, guiding the aerial roots toward the pole. Keep a moss pole lightly moist so the aerial roots grip and feed from it. As the plant climbs, new leaves emerge progressively larger and more fenestrated. This single change is often the difference-maker for a mature-but-flat monstera. For more on training climbing plants indoors and out, see our guide to growing climbing plants.
Cause 4: Nutrient deficiency
Building big fenestrated leaves takes resources, and a monstera in depleted soil or that’s never fed may simply lack the nutrients to do it. Nitrogen drives leaf growth, and a shortage shows up as pale, undersized new leaves and slow overall progress. A plant that’s been in the same pot for years, with no feeding, can stall out even when light and support are fine.
How to diagnose it
Look at the color and pace of new growth. Pale green new leaves, slow leaf production (months between leaves), and a plant that’s clearly root-bound — roots circling the pot or poking out the drainage holes — all point to a nutrient and root-space shortfall. If you’ve never fed your monstera and it’s been potted for a year or more, this is likely a contributing factor.
How to fix it
Feed during the growing season (spring through early fall) with a balanced liquid houseplant fertilizer at half strength every four weeks. Don’t fertilize in winter when growth slows. If the plant is badly root-bound, repot one size up into a chunky, well-draining aroid mix (potting soil with perlite, orchid bark, and a little charcoal) — fresh soil plus more root room often kick-starts a stalled plant. Pair feeding with the light and support fixes above, and the next flush of leaves should arrive bigger and more deeply slotted.
How to encourage and maintain fenestration
Getting a monstera to fenestrate reliably is about stacking the conditions that signal maturity: bright indirect light, a pole to climb, steady feeding in the growing season, and enough patience to let a young plant grow up. The key progression to watch is leaf size — each new leaf should be larger and more split than the last. If leaves are shrinking, revisit light and nutrients first. Keep the plant warm (65 to 85°F), maintain moderate humidity, water when the top couple inches dry out, and prune leggy growth back to a node to encourage fuller, more vigorous regrowth. Do all that, and a flat juvenile monstera transforms into the dramatically slotted statement plant you were after. If you’re also troubleshooting leaf shape, our guide on why monstera leaves curl covers the watering and humidity issues that affect leaf development too.
Frequently Asked Questions
At what age do monstera leaves start to split?
Most monsteras begin fenestrating around 2 to 3 years of age, once leaves reach roughly 10 to 12 inches across. The first signs are usually small notches along the leaf edge before interior holes develop. Strong light and a climbing support can bring fenestration on a little sooner.
Will a smooth monstera leaf develop holes later?
No. Once a leaf unfurls solid, it stays that way — fenestration is set as the leaf forms inside the sheath. The holes you’re waiting for will appear on future leaves once conditions are right, not on the leaves already grown.
Does my monstera need a moss pole to fenestrate?
Not strictly, but it helps a lot. Climbing triggers larger, more fenestrated mature leaves, so a moss or coir pole often makes the difference for a mature plant that’s been sprawling. Well-lit monsteras can split without support, but a pole speeds and improves the result.
Can low light stop a monstera from splitting?
Yes — insufficient light is one of the most common fixable causes. Fenestration is energy-expensive, and a dim spot doesn’t give the plant enough to build split leaves. Move it to bright, indirect light or add a grow light, and new leaves should start fenestrating within a few growth cycles.
Why are my new monstera leaves smaller than the old ones?
Shrinking leaves signal a problem — usually too little light, but also possible nutrient deficiency, a root-bound pot, or stress. Healthy monsteras produce progressively larger leaves. Brighten the light, feed in the growing season, and repot if root-bound to reverse the trend.