hi, have a couple of larged unglazed pots which are a bit of a nasty colour.
i would like them to be covered at least in part in moss or algea or
anything.

a long time ago i heard someone say if you coated pots etc with yogurt you
got a coating of old looking stuff growing on it, soon enough.

is this the best way forward, or am i better coating the pots with something
else?

thanks for any advice. john west