I use coir (or have started to recently) but, other than the fact that it holds on to water like a bog, it is good, as it is environmentally friendly and things. So, I started mixing sand with it (gritty). Is that a good idea? Is there anything else I could use? I've heard using perlite is good, but some people criticise it; the same problem with adding a few stones in with the soil.

Thank you!