You dont need light till they break the top of the soil. Keep the lights on 24 hours a day or at least 18 hours a day untill they are 10" tall then switch to 12 on and 12 off. Make sure they get absolutely NO light during the 12 hours of dark. If you had a more intense light you could veg them longer but with fluorescents I wouldn't because the light wont reach the bottom of the foilage after they mature and it'll be a waste.

Again, good luck