No less then 50* at night. So, I am sure the same goes for daytime. But ideally you want around 70-80*.
You can build a box. 4 sides and a top (no bottom). Slip it over the plant. Use this to induce flowering with a 12/12 light schedule. Depending on your light cycle, you could put the box on around 6 or 7 at night. Take it off around 7 in the am. 12 hours of dark should kick start the plant into flowering.
Your nutes should now have more P-K in the N-P-K rating. P= phosphorus and many consider it a "bloom booster". The K is potassium, and is also needed heavily during the flower period. Less nitrogen is now needed (the N). Does that make sense ? Perhaps look into some Tiger Bloom from fox farms. Cheap, easy to find, and has the nutes you want ( 2-8-4)
If I didn't make sense, just tell me. I'll try and explain it better if I can.