When is the proper time to Flower?

Hey guys
Im about 10 days into a second attempt at growing. Im guessing about 3 inches now, working on its 3rd set of leaves(5points). I am curious as to when I should begin flowering cycle.
Im growing in a garbage can for stealth. its got like 3 feet in height and lots of space diameter-wise. Check my link for pics.

I really am trying to just yield something, not alot or anything. I need to keep this small, and stealth. SO
When should i go into flowering?

Oh yeah Im installing my third 100W cfl bulb tommorrow (so 300W total?), AND Im using natural fertilization now from my aquarium. Im sold on that one.

I appreciate all comments

i like to flower around 1' tall.. the taller and bushier it is when you go into flowering the more it will grow during flowering and a much higher yield with bigger plants