yes sir, mr. saber...

400watts... personally I would not flower the plants being over 10 inches.. no FUCKING way....

reason.. the plants will double in size when you flower and 400watts just doesn't pack a punch (provide enough lumes) to grow anything worth your time beyond 12inches...

Now there are exceptions.. if you are new to growing and need to learn this leasson.. I think that is fine... or if you are only growing 1-4 plants... but once you have 6 or more plants you are 100%, not maximizing your yield..
THIS is assuming "you" don't have side lighting.

I think it is everty 12 inches that a lights lumes drop 50%... scary but true..

Even if you are growing 16 plants in a 4x4 area with a 1000watt HPS.. I would flower the plants at 10-20 inches.... I would never flower a plant taller than 20 inches indoor...

so what do you do if your plant is 30 inches tall and you think that my advice is brilliant...which it is...

you clone the shit outta your beloved mother... down to about 15 inches (although it is a general rule never to reduce a plant by more than 1/3 its starting size) then you let her grow for 7 days... and you flower..

and now you KNOW

zandor, can you please sign off on this post... I think I will have you sign off on all my posts for now on.. you can even give me a fucking letter grade....

i love you