Basil Leaves Curling Under at the Edge

I have started basil indoors under lights. They have been between 2-6" from the fluorescent bulbs and I have pinched them back for bushiness. I am aware that they have experienced some overwatering. Some of the leaves (third pair and beyond) are curling under quite a bit; in fact they are quite distorted on one plant. Can you suggest what might be causing this?

Mature large?leaved basils always curl under at the edge of the leaves, especially the Genovese and lettuce-leaf varieties. If you growing one of these then you are doing everything right. As these plants get large enough to produce mature leaves, their leaves will have curled under the edges.