Last time I said:
> Charles wrote:
> > fighting ourselves?  Of course, sand compacts over time (if not mixed as you
> > suggest with peat, laterite, etc).  Maybe we could look at vermiculite for 
> > the fill.  Although it's a ?silicate clay, I don't think it compacts much 
> I'd use sand to maintain porosity. Don't see much use for laterite in the
> tube though. Better in the substrate where the roots can touch it.
What I meant to say was: Don't see much use for VERMICULITE in the tube... :-)
Of course, the laterite is the iron / magnesium / etc. source in the tube!
 - Steve :%)