I know quite a bit about growing, and I am currently designing a new GroStar model that is Led based. I can tell you this though right off the bat, light is not the real reason plants grow, it is a heat cycle. Picture this, lets say that we want to grow a pound of pot. Now this is going to take say 60 days, and lets say that we are growing 4-4oz plants to do this, following me so far? Now in order to do this grow the plants will use about a 100 to a 150 gallons of water, which no matter how you look at it, has to be turned into vapor, which takes energy, and therefore heat, so Led's are great source of cheap (To Operate) light, the reason we get big buds from Hid is because of all the excess heat that is generated. I am working on a Nat gas/propane powered system that provides the heat and co2, for that cycle, and Led's for lighting, as well as highly reflective material in a contained environment. So experiment away everyone, find the right balance of light that you need, and remember that you have to have the energy for the heat/humidity cycle to operate. Oh, and by the way I invented the GroStar.