This stuff drives me a bit nuts :
I have a small space compared to many people, and it's quite a revelation to watch a plant get bigger...and bigger...then sit there for another three months ripening away.
I don't have the space to do 'proper' Suzanne Ashworth-style seed saving, and I
have decided corn's not a good idea for me.
I let my seed ripen naturally, but I
think that if the seed case is dryish (say it's a radish, I wouldnt want a trace of green), I'd finish drying the pods in a dark, dry place.
A coriander plant's usually pretty pathetic: I plant summer things around it /beside it since it's done its thing by summer time here.