Monstera fenestration (the botanical term for the splits and holes) is the plant's response to maturity and light. It does not come with age alone, and it does not happen on every leaf. This guide covers the reasons your Monstera leaves are still plain, and what to change so the next leaf shows fenestration.
The Plant Is Too Young
Juvenile Monstera leaves are always solid, heart-shaped, and small. This is true even of Monstera deliciosa grown in the rainforest. Fenestration begins once the plant has enough energy reserves and starts to climb.
If your plant arrived as a small specimen with 2 or 3 leaves, expect 6 to 12 months (sometimes longer) before the first split appears. Feeding, light, and a climbing support all speed this up; being left on a shelf in a low-light corner slows it down indefinitely.
Not Enough Light
Light is the most common fixable cause. A Monstera deliciosa in bright indirect light (roughly 1 to 2 metres from a south or west-facing window, or right next to an east-facing window) produces fenestrated leaves. The same plant 3 metres into the room produces solid juvenile leaves, no matter how long you wait.
The rule we give our nursery customers: if you would struggle to read a book comfortably in that spot on a cloudy day, your Monstera probably will not fenestrate there either.
If your home does not offer a brighter position, add a grow light on a 10 to 12 hour timer. A Pianta V2 suspended 30 to 50 cm above the plant is enough for most indoor Monsteras. Full fenestration usually follows within 2 to 3 new leaves.
For more on this, see our guide on whether houseplants need grow lights.
Browse our current Monstera collection if you are thinking about a second plant, or a more mature specimen that already fenestrates.