They will in most case grow much biggger and stronger outside with less effort. Not to mention that it sounds like you do not have the proper equipment for a good indoor grow. If they are still real small like it souds like they are, you can transplant them further apart without killing them if you are careful, if you use good amended soil to bakfill, and if you water right after moving them. If there are very many and its no big deal, you can just pull every other one. In either case, 1 ft apart is too close outside. They will grow, but you will get much more by sepaerating them more. 2 plants that are 3 ft apart will almost always produce more than 3 plants that are 1 ft apart.