Leeks not growning

My leek seedlings have grown to about 8cm tall but don't seem to be thickening up. I must have planted the seeds in trays a couple of months ago (at least) - should I just plant them out or feed them or...

Help!

 

I don't think you should worry. If you only sowed the seeds 2 months ago 8cm is about right, in fact it's pretty good!
You were maybe about a month or 6 weeks late in sowing (though some folk some sow even earlier) I usually plant mine out at about 10 or 12cm height. I'd suggest you give them a feed of liquid fertiliser and plant them in a couple of weeks' time. I honestly don't think the late start wil make a vast difference to your final crop though you'll maybe not get well developed leeks early in the winter.

 

I'm not planning to plant mine out any time soon - end of June will do me, or even early July.

They've got time to bulk up.