I have read on this site that one should harvest just as the scape starts to make its second curl. That is what I now do and it seems to work out well for me.

They make real nice garden snacks about the time they get bent over good into the first curl. They get a little too woody and fibrous for me well before they reach full curl. It is not too late to cut them off for better bulb size then, though. They can be a bit farther along if cooked than if eaten raw.

This post was edited by OldDutch on Sun, Jun 15, 14 at 13:51

Snap one off in the garden and taste it...should be a tender delight like fresh asparagus/onion/garlic flavor. Last year i picked too late and they were very woody and not at all tender...i just missed the tender moment...bummer.
Some varieties will be tender at 2nd and 3rd curl....others just have a first curl edible...
Also depends on your climate and season.
Every year seems a bit different but i'll pick much earlier this year...

Pick too early rather than too late, they'll always be tender, all you'll loose is a bit of length. Once they start to curl and uncurl they get tough.

I like to toss them with olive oil, salt and pepper and do them on the grill until a bit charred.

Steve