Rick said " I've seen the word "compost" used by British gardeners to mean a"finely-divided but airy seed-starting mix"."
In the UK there are two types of "compost". One is what comes from a compost heap and the other is various potting mixes (John Innes mixtures for example). So it does get confusing. Alan Titchmarsh, a UK gardening expert, suggested calling the former garden compost and the latter potting compost in a newspaper article on the subject.
There are different John Innes composts for different purposes, expained here:
http://www.gardeningdata.co.uk...
I remember I used to use these when I lived in the UK a looong time ago.
