Oudoors, the pot decides the size of your plant. Your not getting a 10 ft plant from a 2 gallon pot. I think its gonna do with the size of your reservoir. If your roots can grow, so will the plants.
I suggest moving the light down to 15 inches. As long as the temp at the top of the plant is not too hot. Place your hand above the plant. As long as its not burning your skin it will not burn the plants.
Those bugs are eating the hell out of your plant. Need to get you some garlic powder, mix it with water, put it in a spray bottle and lightly spray each leaf. Garlic powder not garlic salt. Very important.