Jennifer, I have the light on for atleast 12hrs. at night and I do have them in a south facing window, but I do not rely on this to give them a consistent amount of good light. I do this with my seed grown plants started in the winter months here. When they have reached 1yr., then I do not put them under lights. They are on there own devices and go dormant or stay in leaf.
Best not to let seedlings go dormant until atleast 1yr old.
I was concerned years ago about how much hydro the Florescent bulbs would cost to run, but pleasantly they are quite cheap to run.
Rick
