I don't think it's poisonous - I have lots of mounted plants that have
"grabbed" the back of the adjacent slab without an issue. The outside is a
lot more porous, so maybe that's the reason for the preference.
--
Ray Barkalow - First Rays Orchids -
www.firstrays.com
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"Wendy" wrote in message
...
I have noticed that over the years I have mounted some orchids
on the inside of a round hollow piece of cork.
The plants struggle & I have lost a couple.
The inside of the cork has a dark lining if you will on it.
Could this be a poison to the plants?
Cheers Wendy