Control on/off times for up to 6 lights, using 2 sockets - grab a Loadstar Lighting Timer Contactor.
With a single lighting contactor for multiple lights you also you reduce the amount of cabling on your grow room floor
It has a segment timer (set light on times in 15 minute segments).
Loadstar 4 - 4 x 250W lights or 4 x 400W lights or 4 x 600W lights or 2 x 1000W lights
Loadstar 6 - 6 x 250W lights or 6 x 400W lights or 6 x 600W lights or 4 x 1000W lights