Kenni gave good advice on the "it depends" part.

Barbecue charcoal - no
Most is hardwood charcoal, not the stuff made from pine chips sold for
grilling.

Mulch bark - no
That's usually pine, too. Fir bark is the standard, although it's hard to
find good stuff nowadays, so most people have been moving to coconut husk
chips.

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies, Books, Artwork, and Lots of Free Info!

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"keith" wrote in message
...
any advise on potting mixtures,I have read in the RHS encyclopedia use 3
parts bark chippings,1 pt perlite,1 pt fine charcoal.Can the charcoal be
ordinary barbeque charcoal washed,can the bark chippings be the sort you
get
from garden centres (for mulching)or does it have to be sterilized?
thanks keith