Growing medium
Randall P. Linke (Thu, 12 Jul 2012 15:32:10 PDT)

On the subject of perlite, I use it in my larger pots so they are not so
heavy when I move them. As that which is near the surface has a tendancy
to float up I top the upper three or four inches with the same mix as in
the rest of the pot only without the perlite.

I have been mixing drystall with sharp sand and compost in varying
proportions and have not encountered an clumping issues.

Randy,
Monterey Bay Region, CA