Just a little note of advice. I see in the pictures what looks like aluminum foil on the walls behind the plants. If that is indeed aluminum foil? You DO NOT WANT TO USE THAT. Aluminum foil is a reflector of IR radiation but lousy for reflecting the higher frequency light that the plants need. It looks to our eyes like it is doing the job but it isn't reflecting the light that our eyes can't pick up as well (that the plants need).
Remove it and get either a grow tent or get some "panda" film or reflective Mylar. If you have a Lowes or Home depot near you, they have an insulation sheet that you can buy that comes in rolls. Its like bubble wrap that has had reflective Mylar made onto it on both sides. I use it to line the walls of my grow as it is very easy to use and work with.
For MJ its all about "light energy". MJ is a high energy plant, like fruiting plants, and it needs loads of that high energy light to perform at its optimum ability. The spectrum of light that plants use for the all important chemical production is a high energy light which is key for MJ to build the complex molecules that we want. that is why we press the point of having proper lighting and building or buying a properly reflective space to house the plants.