Monstera leaf split pattern: why my 3-year-old has zero fenestrations
My Monstera deliciosa hit 3 years old in March. Twelve leaves, all solid green, not a single split. I was watering correctly, fertilizing monthly, but no fenestrations.
The problem: light. It was 5 feet from the east window. Moved it to 3 feet. Six weeks later, leaf #13 emerged with the classic Monstera split. Now on leaf #15, and every leaf since the move has splits.
If your mature Monstera isn't splitting, it's almost always light. Move it closer. Bright indirect, not direct sun. You should see splits within 2-3 new leaves.
— Elena