My lettuce seedlings are doing extremely well under grow lights. I had been having the same problem I often have with seedlings — sad, spindly growth, even after a few weeks.
I put a new batch of romaine ‘Freckles’ seedlings under lights 20 days ago. Just after my last update, I noticed that the roots of the seedlings had reached the outside of the peat pots I’d planted them in, so I transplanted the seedlings into bigger pots. Here’s what they looked like then and now.
The time to maturity is 55 days, so we’ll see how it goes. In summary: Grow lights are awesome.