Latewood â?? Thanks for this thread. I understand the different types of lights and their various functions, but Iâ??m confused as to the number of lights needed for a larger (20â?? x 20â?? x 8.5â??) grow room.

Assuming that the room will be used exclusively for either veg or flower at any given time and that the lights will be stationary (i.e. no tracks. Obviously they will be adjustable vertically.) How many HID lights in what kind of configuration would be necessary for optimum crop yield? I guess another way of asking this is what is the optimum effective footprint of a 1000W HID light?

BTW â?? if the plants get too big and bushy, I will supplement with fluorescents in between the rows of plants.

Any advice you can offer is greatly appreciated!