I need some advice on growing in a small area. My space is a 3 ft by 3 ft corner of a room; the height is about 7.5 feet. I have one 400W HPS light assembly. I want to grow a single crop from seeds in soil containers. How can I grow plants as short as possible in order to have more plants under the light? Also what are some good strains that grow short plants and how high do they grow?