....its so small because you are using 1 18w cfl. You'd get faster growth sticking it in a window sill. My current ladies are around 2 weeks and about 4 times that size. Get ALOT more light on that.
I agree at least throw 2-3 18 watters on there. the sigle cfls are perfect for seedlings but once you get those true leaves they need light! Another thing is the cfl should be almost touching the plant. After a few inches they start to loose a lot of lumens which make them pointless if there no close.