Mathematically speaking, Sun = 10,000 lumen per square foot. 1000w HPS = 140,000-200,000 Lumen. If you used 5 HPS lamps (one on each side of the plant plus the top), @ 150,000 lumen, it would total 750,000 lumen for that one plant. Assuming that the plants both grow to be 2ft x 2ft x 4ft, the...