perlite, pumice,

Tue, 04 Jul 2006 15:41:00 PDT
Even out here in my rural part of California it is difficult to buy large
bags of the coarse graded perlite.  They seem to only have or want to
deliver the so called medium, which has lots of fines in it.


----- Original Message ----- 
From: "Joe Shaw" <>
To: <>
Sent: Tuesday, July 04, 2006 3:14 PM
Subject: [pbs] perlite, pumice,

> Hi Gang,
> I can only second the frustration voiced by John Lonsdale.  I cannot find
> good perlite, and a search for pumice revealed no suppliers within 200
> of Houston, TX area.  Neither the bonsai society nor the various cactus
> societies had good leads.
> I've given up on finding good perlite (or pumice), and have started using
> substitutes; I don't know if they are the best, but they are the best in
> terms of availability and my willingness to spend money.  I use scoria
> rock such as is used for landscaping) and Styrofoam peanuts.  Both have
> drawbacks and benefits for me.  Styrofoam peanuts are essentially free for
> me from my workplace.
> Because it is so rainy here, I plant cacti, some bulbs, and many agaves,
> etc., directly in scoria.  I fill the container with scoria, or a mix of
> scoria and Styrofoam peanuts.
> Then, I pour a soil mix over the chunks.  Sometimes, the soil mix is only
> 10-15% organic matter, so the whole affair is really 100% scoria (by
> volume), with other materials filling some of the interstices.  Along with
> fungicides, extra water in dry periods, and other measures, this seems to
> satisfy many xeric plants.
> The whole perlite size-reduction issue is perplexing.  I wonder if we
> growers who have noticed the difference just don't provide a large enough
> market for the vendors.  I've tried some other possible subsitutes such as
> Turface, and find that expanded clays hold too much water.  Drystall is
> option (horse bedding material made from volcanic aggregates), but it is
> apparently not offered in this area.
> Cordially,
> Joe
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