Mix the right soil
Bagged "all-purpose" potting soil is too dense for most houseplants. Pick your plant and how much you need - we'll give you the recipe in simple parts and litres, so you can blend a batch that drains the way those roots actually want.
⚠️ "Parts" just means equal scoops - a part can be a cup, a yoghurt pot or a bucket, as long as you use the same one throughout. Always pot into a container with a drainage hole; even the best mix can't save roots sitting in trapped water.