if you can add more light, do so. it won't do anything but help, as long as your temps don't get too high. as far as feeding, soon as you have an actual, physical bud (ie marble size), start feeding. n p k you want a higher p value. i use 15 30 15 for my outdoor plants. this may be to potent for your indoor grow, so check behind me. maybe a 1 5 1?

hope this helps,

love, brooke