they are ready right from small pods. Eat the small ones whole
very early, then as they grow bigger pod them and then by now (in
the south) they have developed a skin on the bean itself which,
if they are to have any flavour you need to blanch for 2 minutes,
refresh and peel the beans.A right pain.

If you knew all that already then the answer is test a sample
bean!
--
Mike Reid
UK Walking "http://www.fellwalk.co.uk" -- you can email us@ this site
Eat-walk-Spain "http://www.fell-walker.co.uk" -- dontuse@ all, it's a spamtrap
Photos "http://www.lawn-mower-man.co.uk"