Monsteria Split Leaf

Question

what is causing brown spots on leaves – its “within” the leaf, not edges etc. it gets water once a week, has sunlight from all sides, big pot, seems fairly happy but hubs is concerned about the brown spotage…..no bugs, not on edges, just a small patch of brown in the leaf. thanks love your help!

Answer 1

It could be too much sunlight. They need indirect light so if yours is getting direct sun, it may be burning the foliage. Plus, make sure the pot is not too large. If it's much larger than the rootball, it is getting too much water, because the extra soil is holding unnecessary water. Cold air from an air conditioning vent could cause brown spots.
Are there yellow margins around the spots? If so, it could be a fungal spot. Start by removing the leaves with brown spots. If it's several, don't defoliate the plant. Remove the leaves in stages.

These articles below will help pinpoint the exact problem.

https://www.gardeningknowhow.com/houseplants/philodendron/split-leaf-elephant-ear-philodendron.htm
https://hgic.clemson.edu/factsheet/houseplant-diseases-disorders/
https://extension.psu.edu/philodendron-diseases
https://www.gardeningknowhow.com/houseplants/philodendron/brown-philodendron-leaves.htm