Onions from seed

[Barmaid]

I've grown some aisla craig and some red baron from seed this year. Seedlings are in the polytunnel, although I am now hardening them off.

Do I need to do anything with them to plant them out? For instance, its been suggested to me that I only need 2 inches of roots and should trim the tops.

Any more tips, please?

[Clanad]

Here in the U.S., when the onions get just to the point of going to seed (with seed pods developing on top) we simply step on the tops and break them over. This assures development of the onion bulb, but not until then...