Granite as a source of micronutrients

John Lonsdale
Wed, 09 Nov 2005 05:58:00 PST
Hi Linda,

I did the 'quickly Googling' because I'd come off the tennis court at 11:10
pm and was ready for a shower and bed!  

It is kind of hard to envisage how something as apparently hard and inert as
granite can release sufficient material to be useful, but it does.  We are
talking concentrations in the low ppm, and below in some cases.

I have never considered using the grit as a starter medium but there's no
reason why it might not work.  I would certainly experiment - your own
experience beats the heck out of reading about the 'right' or 'only' way to
do things in books.

I've never grown anything under lights, which I where I assume you have the
fungus gnat problem?  They generally prefer warm damp organic conditions.  A
1/2" layer of granite grit on your seed pots/trays and letting them dry out
somewhat between waterings might be a good place to start? You can whack
them with an insecticide to get the levels down quickly whist you adjust
your conditions.



John T Lonsdale PhD
407 Edgewood Drive,
Exton, Pennsylvania 19341, USA

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