Be sure to get a good timer to automatically turn the fixtrue on and off. I can't tell you how long to set the timers for, but I picked up an interesting tip from the AOS webinar last week, on growing under lights. It involves reducing the time the lights are on, by 1 hour in October, another hour in November, and another in December. January remains unchanged, Add an hour in February, and then one more in March, and again in April. Hope this helps.