A 250 watt fixture will supply enough light to cover a 2.5 foot by 2.5 foot grow area. (6 plants or less)
A 400 watt fixture will supply enough light to cover a 4 foot by 4 foot grow area. (12 plants or less)
A 600 watt fixture will supply enough light to cover a 5 foot by 5 foot grow area. (18...