You had them in 2 inch pots? ahahaah thats crazy dude.
Also I should think you want atleast a 10 gallon tub to veg/flower in. The ferts you are using are really powerful, and not really designed for cannabis growing I don't think.
One think that could also contribute to you small buds is your light. If using CFL's its highly recommended to double the watts you used to veg, to get larger more dense buds.