We inherited the shelf and the B man got these fluorescent lights on a blow out sale at Canadian Tire. I'll confess to not really knowing what I am doing except to say lights are used to prevent stems of the vegetable plants from going spindly. The stems ARE looking strong, especially on the pole beans and cabbage. Some are even ready to start the hardening off process. Only problem is we got snow last night and Spring seems to be long in coming. Still, we plant on ever hopeful.