Why does my iguana not grow!?

i feed him 2 times a day. at 2:00 then around 5:30 around there any ways i heard that iguanas like to eat at 10:00 in the morning but he does not like to eat at that time so i just feed him at lunch time. i feed him collard greens,mustard greens,turnip greens,water cress and i put ernut squash with it. or maybe its the humidity. i don't think there's humidity in the cage and i have uvb light and a regular light bulb and by regular i don't know what type. so what lights do i need? tell me the exact name of the lights. i hope u can help me please!!!