Re: CPDig. 629 - media
DAVIDDOG@aol.com
Thu, 22 Feb 1996 09:40:44 -0500
When I was in college studying Horticulture, flouride toxicity was just being
investigated; while water flouridation was shown to be a possible source of
toxic levels of the compounds, soil medium sources especially perlite was the
most common cause of problem levels of flourides.
I personally have never heard of a home test for flourides and so have no
recourse but to avoid the stuff. Its easy to do since I hate working with it
and think its ugly - also the dust is dangerous, don't breath it; moisten the
bag of perlite before pouring or stirring up your media.
Sand is what I use in most of my CP mixes. I use a couple of grades of pure
white silica sand. Most often I use No. 8. Its available inexpensively in 100
lb bags from sandblasting suppliers.
Follow the same precaution of moistening it before moving or mixing. I wash
the sand briefly first, but its usually prettty clean. I often topdress with
sand to keep fungus gnats at bay.
Has anyone used coarse pumice in any if their mixes? I currently use it for
my orchids and bromeliads and have two small Nepenthes newly potted in a mix
that is 1/3 very coarse pumice, with tree fern, coarse peat, and NZ Sphagnum.
How about Rockwool? No one seems to have mentioned it lately.
Thanks to all,
David
DAVIDDOG@aol.com
daviddog@creative.net