Lighting requirements are variable to grow room size and funds. If useing HID (Metal Halide / High Presure Sidium) then 400W=3'X3' 600W=5'X5' 1000W=8'X8' these figures are also variable but those room sizes are about average. Any smaller of a space then CFLs (Compact Floresent Lights) can be used @ about 40+ watts per in Growth, and 150W - 200W per plant in bloom.as far as lighting any type of growth other than cloning requires a minimum of 600watts (imho), otherwise yield is compromised.