Well-drained growing media (was Oh No! A Boophone disaster!)

totototo@telus.net totototo@telus.net
Tue, 06 Oct 2009 17:26:13 PDT
On 5 Oct 2009, at 18:02, Leo A. Martin wrote:
> I have wanted to try some of the larger-particle perlite, often used for
> insulation, but I have been warned much of this is very high in fluoride 
> and toxic to plants.

Change that "is" to "may be". If you feel you must use insulation grade perlite 
in spite of these warnings, you can mitigate the risk by adding lime to the mix 
as calcium fluoride and magnesium fluoride are very insoluble and thus the 
presence of Ca++ and Mg++ ions in the soil will tend to soak up any F- released 
by the perlite.

Rodger Whitlock
Victoria, British Columbia, Canada
Maritime Zone 8, a cool Mediterranean climate
on beautiful Vancouver Island


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