In article ,
Tom Gardner wrote:
I may give up
on the oyster shells, which have lasted the best part of a decade,
though :-)

What did (past tense, presumably) you think would
be the breakdown process? I known chickens work
well

Yebbut, you have to break them up first, and that would be enough
in itself. The way that such things break down is that the usual
bacteria destroy the connective tissue and rain and soil acids
then dissolve the minerals. Weight-bearing bones of large, mature
mammals have a very high mineral content and take ages, and most
shellfish shells have more, but oysters seem to be exceptional.

I keep chucking them back, as I do with uncomposted bones and other
shells, but I think that I am going to start removing them. But
mussel and clam shells soften enough to break up after a few years,
and add a bit of lime. Or I may put them on a paving slab and hit
them with a club hammer :-)


Regards,
Nick Maclaren.