the formula I=L/D²

Lumens received are a measured in watts-per-square foot or foot-candles
Zandor Reviewed by Zandor on . High Intensity Discharge Variances Could any one clarify the real variances in the growth variations of a 400 watt HPS and a 1000 watt HPS bulb? I know the 1000w is better but where do you think the 400w stands in cannabis growth? Rating: 5