A soil mix for most tropical plants is fluffy, airy, chunky, has air pockets and is excellent at moisturizing the thick roots while at the same time providing a greatly aerated environment.
This soil should mimic the conditions found in rainforest dirt which contains a lot of leaf litter, organic debris and nutrients - perfect for fast-growing plants that can be a bit sensitive to dense and heavy soils.
The components in store-bought soils for tropical house plants may differ a lot, so you should look for chunky soils that mainly consist of compounds such as peat, coco coir, bark chips, perlite, sphagnum moss and compost.
Mix you own
It is also easy to make your own Tropical soil by mixing these amendments:
All-purpose potting soil
Chopped sphagnum moss