I jsut did this. I had the lights close on the dome for a few weeks. I was using some bigass rockwool cubes and waiting for the roots to show, they didn't. So finally when i realized my plants were root bound i transplanted them and could have had 2 more weeks of growth. My advice is to transplant them into a medium that keeps the bottom of the plugs wet at all times as soon as you see the second set of leaves...