how many plants under 400w HPS??

How many plants you think i can get flowering out of 400w HPS??

it depends on how big they are.
You can have one huge plant, or tens of small ones.
Max i have had is 7. Since then I haven't gone above 3.
You pretty much get a similar amount of ganj however you do it.

Smaller plants obviously have less time in vegging, so there is that advantage in having a large number.
But police take into account the number of plants you have, and not their size. So there is also that disadvantage.
I simply found fewer plants to be less hassle.

I've done four 4' White Widow plants in one run, then I ran a clone-to-flower perpetual in a 2x4x5' tent with a 400w HPS. I had three stages of flowering plants (3 cycles of 3 weeks) for a total of 24 plants under the lamp at all times (again, no veg time was provided, so the plants stayed nice and small).

Check out my 12/12 sig thread to see how they fit.

-spek