The majority of commercil grows around here are done in Promix soiless mix. Easy and cheap to set up with no tubes, pumps ect. to worry about. It is a pain to get the soil and dispose of it, but it beats moving pipes and all the other stuff that goes with a hydro grow. Promix with grow bags makes for an easy and cheap set that is very productive if done correctly. Also, alot of commercial growers reuse their soil by mixing it with dolomite lime. After three crops it is disposed of, so this lessons the amount of soil going out. Usually they find a town house or home that has a garage attached. That way stuff can be brought in without anyone noticing.
TGT
TGT