This is the first time I have started my own leeks from seed; have bought little pots of them at the local nursery before.

My seedlings are doing quite well, but I do not envision being able to transplant them outdoors for at least a couple more weeks because of the cold weather and very wet ground. In the meantime, they are now 5-6" tall. I know when planting onion plants that I get by mail order, I always trim the leaves back a bit before planting (as per accompanying nursery instructions) and quite soon new growth does appear.
But should I do the same with these leeks? I can move them lower so they are not touching the lights, so I am not too worried about it. Just wondering if a slight clipping would make them sturdier.

When I plant them into my beds outside, I know to plant them down in a pretty deep trench and fill in as they grow. I always get a nice long white part on my leeks.

Thanks in advance for any suggestions!