Not so. In hydro, your plants are totally dependant upon you for food once they have shed their seed casings. If you don't feed them at all, they will stall and die unless your water is high ec and suitable. You need to start at quarter strength feed and slowly work your way up. Use veg formula up until the end of stretch (10-14 days after the switch to 12/12).
Phillip, I am suprised at you. Maybe you misread the post? You should know as well as I do that feeding a hydro plant just water for several days, let alone weeks will kill it.