This is my average grow and Yield
Start from clones at 8 inches in height
450mm wide tubs
hydro in rockwool - PH 5.5 all the way through the cycle
Each tub 500mm from the next in a grid formation
Each plant under a 1000w HPS (remember it makes no difference about the number of plants per square meter, it's the yield per square meter per 1000w)
5 week veg
LST, pinching and SCROG techniques employed (never top, too stressful and delivers lower yields compared to LST and SCROG)
Each plant will be at least 1200mm in diameter and no more than 400mm in height before switching to 12/12 (Great big dome shaped things...)
80-120 Heads per plant (tie her down every second day and remove every leaf that covers a growing head)
No snake oil, basic nutes only
No attention paid to flower time - simply waiting for the triches to turn dark amber (could be 7 weeks, could be 10 weeks)
Average Yield per square meter 1100g (Thats almost 40oz per plant/square meter for my American chums BONE DRY)
If you want 3-4lbs per plant hydro then the above remains the same apart from doubling the distance per plant, veging for up to 10 weeks and having 2000w per plant
Yield = Tub size + tub spacing + light per square meter + LST and scrog - Simple
I guess everyone on here would add an extra inch onto their dick measurement when asked how big it is, but mines big enough to take an inch off...