if you just have 1 plant, 400hps is plenty. i would put up to 4 plants under a 400 watter
" i wanna grow atleast a pound of chocolate thai dry bud ."
a 400w hps is not enough light for how big his plants will be after 3 months veg outside.......much less getting a lb off a 400w hps from 4 plants.
original poster-you should keep them out for flowering too, just bring em in at night if temps a problem, im 99.9 percent sure your gonna get a much bigger yeild outside, outside its easy almost to grow plants that will yeild 1 lb+ easy....dig a big ass hole, get some good soil and add stuff like fishguts and that sort of stuff, start your plant now, veg it inside till about middle-late april or may (at least thats when my area is about ready and the gals are about 3 feet tall , depending on where u live it may be later or earlier for you.), plants grow monstorous all summer and you get tons of buds in the end.