well the thing about vertical is that you do not lose any light so is much for efficient. with a reflector half of the usable light is sent upwards to bounce around and get reflected back down on the plants.. its debatable how much you actually lose.. some say half but i would say 20 to 30 percent at least. also with a reflector you lose more light by beaming it through the glass panel.
so with a vertical setup you dont lose any light to the reflector or the glass panel. this translates to more efficiency because more usable light is transferred to the plant. you can also squeeze more plants in a smaller area. for instance my footprint is only 5x9 total, which would be taken up by just the 15-20 ladies i have in soil...
also since hot air rises, there is very little heat, you just need a fan blowing up on the light and you dont really have any issues.. i was definietly surprised.
in the end it just translates to a higher gpw.. for instance the best yield i have ever had in a flat garden without co2 enrichment was just about 1gpw.. a little over 2 lbs per 1k light.
other vertical systems i have seen online and in person easily do 2lbs per light. some can do about 3 lb per light and one i have seen recently gets over 4lbs per light.. he has a serious wall of green with well over 200 plants for each 1k he uses.
this system is a spinoff of a system a guy named heath robinson did on another site which achieved 1.5 gpw. i am planning on getting 1.1-1.4 gpw on this grow. these are numbers i have never seen on any flat garden! that is what sparked my interest. once i get it dialed in i would like to build a sealed in system with serious co2 enrichment and hit 2 grams per wat.. now that would be something!
FLo