a standard 1k will cover 16 sq ft 4x4, but with certain hoods like a XXL you can cover 20-25...but there has been debate about how the 5x5 hoods might cover more space but have less lumens per sq foot. in the hood test thread the blockbuster 4x4 had some of the best lumen coverage. and my friends get 1lb out of a 4x4 all the time with 9-10 plants.