Hello Ambedexteras, When I started I was running 18/6 under 250 Watt ballast. I would have to say that I switched to the 12/12 cycle around the 5th week mostly due to space constraints (my largest plant was starting to grow into the ballast) Essentially from what I have read for most indoor grows with space constraints you can switch when the plants reach around 18 to 24"(which is what I have done) My system is a small hydro system capable of 6 decent sized plants. As for fertilizers I use Flora nova bloom and grow with Botanicare Pure blend tea as a supplement during the Grow phase and I have switched to Kool Bloom during the bud phase as a supplement, which so far seems to be working for me. If I had the space I would try to incorporate a SOG type system that way I could incorporate a metal halide light or some high powered fluorescents for the Veg stage. As for when the budding starts it is noticeable after about 10 days after your switch to 12/12, just make sure during this switch that no light gets into your grow area after the lights go out. I hope this helps out.