Plant your Monstera in a container with drainage holes and use a good quality potting soil with peat moss that drains easily. The plants thrive in dense, nutrient-rich soil, but don't do well in potting soils with bark or compost. If your container doesn't have drainage holes, make a few in the bottom.
What is the best soil mix for Monstera?
Monsteras like a mix rich in peat (I use coco fiber which is similar but a more sustainable alternative to peat moss) and compost which is well-drained. They grow on the bottom of the tropical rainforest floor and this mix mimics the plant materials which fall on them from above and provide the nourishment they need.
Can you use cactus soil for Monstera?
Monstera thrive in a well-draining potting mix; a premium potting mix is a good place to start, but a cacti/succulent mix or even chunky orchid mix works great to help with drainage.