Instead of grit, baked loam, for example, can succesfully be used as botom layer. It makes the substrate drainable and it also takes up water. The only reason for using grit, is, in my opinion, not finding anything better.

Layering substrate is a pretty outdated technique and according to soil physics unhelpfull.

leatherback wrote: Layering substrate is a pretty outdated technique and according to soil physics unhelpfull.

I knew it was coming...

Clicio wants interesting......

Monday night the subject of the monthly meeting was soil.

About half use akadama, at least a third add organics. Some use kojima, some use perlite, I think nobody mentioned sand. Some use expanded aggregate from a local cement factory.

Organics are coffee grounds, garden store pottisoil, composted pine needles, pine bark, pine cones (this is Alabama and we have lots of pine trees). Pine bark and pine cones can be chopped by hand, ground up in a food prepared, coffee grind, you name it.

It looks like anything works.

Here in Japan, standard mix is Akadama with Kiryu-sand, and depending on species you add a bit of this and that.