not sure on root development but dont think it ever stops developing roots.
most plants 3-4 weeks into flowering will stop growing and concentrate on bud development but some long flowering strains may continue to grow for longer.
bejay Reviewed by bejay on . a couple of questions... I have four plants on day 12 or 13 in flowering, what point in life does root development stop, or does it? At what time in its life does it stop growing(heigth) and concentrate on flowering? Rating: 5