Water retained by various soil ingredients

Eugene Zielinski eez55@earthlink.net
Wed, 24 Oct 2012 18:47:57 PDT
Diana brings up a good point.  I've found that the horticultural grade
perlite avaliable in small packages in "big box" stores, etc. contains a
large amount of fine material.  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.
The coarse grade of perlite is much used in orchid circles where it is
often referred to as "sponge rock."

Eugene Zielinski
Rapid City, SD

> [Original Message]
> From: Diana Chapman
> To: Pacific Bulb Society
> Date: 10/24/2012 8:46:53 AM
> Subject: Re: [pbs] Water retained by various soil ingredients
> As Leo pointed out, there are other kinds of perlite.  I couldn't do 
> without perlite, and use huge quantities of it, since I have hundreds of 
> pots, some very large, and moving and carrying them is a daily task.  I 
> started using the better quality perlite some time ago.  It has been 
> specially heat treated, and comes in three grades, the medium one is 
> about bean sized, and it has no dust or fines associated with it. 

More information about the pbs mailing list