Re: Perlite

John Taylor [The Banshee] (rphjt@minyos.xx.rmit.OZ.AU)
Tue, 16 Nov 93 08:33:54 +0000

>> Well here's a basic question that I was wondering about. Just what
>> the devil is perlite? For that matter, I'm not entirely sure what
>> vermiculite.
>
>Perlite is a glassy, silicate, volcanic rock with a pearly luster and
>many minute concentric cracks.
>
>Vermiculite is "any of a number of hydrous silicate minerals resulting
>usually from alterations of mica and occurring in tiny, leafy scales that
>expand greatly when heated".
>
>My understanding is that perlite is as inert as "puffed" glass. It has
>no nutritive value to plants, and has no effect on pH. Vermiculite, on
>the other hand, is mildly alkaline, is pH buffering, and does provide
>some mineral nutrient value to plants.
>
>I mostly use Vermiculite for mexican pings, and perlite/peat for a less
>soggy general cp mix.

Just a "warning" about the mysterious Perlite - on the packet that I bought
was a health warning that the dust may be hazardous - akin to the dreaded
Asbestos, I guess. I guess it would be prudent to make sure that you wet
the stuff before use and take some sort of precautions...

The only time I bothered to use the perlite is for my Brochinea reducta, using
a mix suggested by Allen Lowrie (who I got it from). I was a bit disappointed
with the tiny plant I received for my $10 or so (and I thought that Heliamphora
plantlets were expensive ;-) ), but it has grown very well with little TLC,
and is holding water now (it's a few inches tall).

+-----------------------------------------------------------------------------+
| John Taylor [The Banshee] | Royal Melbourne Institute of Technology |
| rphjt@minyos.xx.rmit.oz.au | Department of Applied Physics |
| MOKING IS A HEALTH HAZARD. | Melbourne, Victoria, AUSTRALIA |
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