like llama said 1 for about every 4 feet is good more light better yeld, remember ventilation. if you have a glass coverd air cooled hood you can get away with your lights being fairly close to you plants. with more light and a room that size you should have a great grow good luck!
imagoober Reviewed by imagoober on . 400 watt hds my room is 12 feet long by 4.5 feet wide and 7.5 feet high and have a 400 watt is this enough, it is on a light mover and the walls are painted white Rating: 5