Tough to answer without more details, but the important thing is that the medium/roots not dry out. What's your medium? Rockwool? What size? Or coco or something like that? In what size pot? What is the climate like where you are? Is it very dry or not? That would affect your feeding schedule. Is it very warm/hot? That would, also...
I used to feed 6" rockwool 4 times a day, at 6 am&pm and 12 am&pm. That was in flowering; in veg, they rarely to never needed watering more than once or twice a day. It was very dry where I lived, and at high elevation so it rarely got very hot.
Whether the lites are on or not should make no difference; the important thing here is to KEEP THE MEDIUM WET/DAMP. As long as that's done, the plants will take what they need from your nutes, which are nestled snugly in your medium, when they need it.
That's what I think, anyway.