My question is - whether I can use sand instead of pumice, or perlite for drenage when making potting soil mix for my Peace Lilly? And which sand would be the best for this function, and in which proportion can I mix it with potting soil?
You can use sand but I do not recommend it. It adds a lot of weight and different water retention than perlite and other substrates. Plus sort of compacting the soil mix making it harder for roots to grow.
Drama Free Zone. What every gardener loves the most, Begins and ends in rich compost. (Tina)