From what I've read. 50 cm's or 16 inches with HPS.My questions .......... never used HPS so...........
1. Its 100w hps I will be taking it out of the box it is in and wonder can i attach the balast (not including a cap doesnt have one) to a piece of wood or will it get to hot and ciatch fire?
I will attach bulb and reflector to L bracket and to wooden frame.
2. How far does this 100w bulb need to be from the top of the plant?
I know it cant be as close as CFL's (1 to 3 inches).