showering the flowering ladies

hi all. ok my plants are 6 weeks in and i want to start flowering. there going to be under a 400w hps. the room is totally dark, when its dark so im not worried about stray light getting in, and its also going to be 12-12. what else do i need to do to initiate the flowering cycle? and get good buds, assuming i have ladies.

Feed them with nutes higher in phosphorous and potassium and lower in nitrogen. This helps initiate flower and get nice fat buds.

when u switch the lights, switch to nutes with P and K like 0-10-10.