that's a hefty harvest every 35 days! the kind of grows everyone wants to see haha. I haven't personally seen a documented grow that got that much, that frequently, but of course it can be done. I would assume it would most likely be a perpetual grow setup. If i were to try to yeild that much i would have two flower rooms on 24 hour flip flop with 3 1000w in each room.(you can buy flip boxes that would allow you to run 3 1000w ballast 24/7 and it just converts the nominal power from one flower room to the other every 12 hours and there are no 12 hour power spikes because you have a continuous 3000w going 24/7). You would also need a veg room going with a few mothers in it. so to make an easy example out of it lets say you want a total of 30 plants in each flower room. you get some mother plants going in your veg room, once they are big enough to get 30 clones going. you chop 30 clones and wait about 2 weeks for them to root before transplanting for veg. You now have your mother plants and 30 vegging plants going in the veg room. You plan on vegging these plants for 30 days (this does not include the 2 weeks for rooting the clones). once the clones have been vegging for about 16 days, you take 30 more clones from your mothers and get them rooting. 2 weeks later, your 30 clones are ideally rooted and ready to be vegged, your 30 vegging plants have now vegged for 30 days and are ready to be put in one of your flowering rooms ( assuming they will be there for 60 days), and you still have your original mother plants. So at this point there are 30 plants in 1 flower room, no plants in the other flower room, 30 rooted clones just beginning veg, and your mother plants. after 16 more days, you take 30 more clones from the mothers and begin rooting. 2 weeks later, you have rooted clones, 30 plants that have been vegging for 30 days, 30 plants that are half way through flower, and your original mothers. You move your 30 vegging plants to the other flower room, transplant your clones to start their 30 day veg, and you still have your mothers. assuming you keep taking clones after 16 days of veg for the 30 that are vegging, 30 days later, one of the flowering rooms will be ready for harvest, you have 30 plants that have vegged for 30 days and are ready to be moved into the flower room you just harvested, you have 30 clones that are ready to be transplanted for veg, you still have your original mother plants, and you will be ready to take your next batch of clones in 16 days. Assuming you already have experience under your belt and are capable of getting 1.66 pounds per 1000w light you will hit your goal of 5 lbs every 30 days.
Note, this is a basic model for a perpetual harvest. there are a lot of ways to do it. the model assumes you can get 1.66 pounds per 1000w light, you can successfully root clones in 2 weeks or less, you are not afraid to have over 100 plants, you don't want the 12/12 power spike of having 1 flower room with 6 1000w lights going, and multiple other factors. The bottom line is that it is a lot of blood, sweat, tears, and money! however, it's doable. hope this helped out haha
not a whole building 
