Water retained by various soil ingredients

Michael Mace michaelcmace@gmail.com
Thu, 25 Oct 2012 09:44:58 PDT
Eugene wrote:

>>I once sifted (outdoors!) about a quart (liter) of dry perlite through 1/8
inch (about 3 mm) mesh and found that the fine material made up about 1/3 to
1/2 of the total volume.  It may be that this fine material is retaining
most of the water and causing problems.

I think that's probably the problem I've been having.  I don't have the time
or patience to sift the perlite I get from the garden center, and also don't
want the exposure to perlite dust that would cause.

I've found a local source for pumice, in the form of a product called "Dry
Stall."  It's used for horse bedding, but is a uniform size, is free of
fines, and doesn't cost much in the volumes I use.  So I think that's what
I'll try next.

I'll sift a small amount of perlite and re-run my water absorption test with
it.  I understand the very valid point that it's porosity that matters most,
but I still think the absorption information is a useful data point.


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