how much light would i need!

I am planing on doing a nice grow qustion how much light would i need for a 12x12x8 ft room i have 2 400 watt lights now.but i need to be correct on this for the amount of money i will be spending it needs to pay off ya know.

Add 12 Bic lighters and a picture of the sun That should do it ...

lol no that wont work i need anwsers man

400w lights .. what kind

Hps ?

i have M/H and HPS i have a switchable ballist

12*12 is a large area, 144 square feet. Bare in mind you want around 7k+ lumens per square foot for good results. If we go along with the 400w HPS ballasts; each gives around 55 000 lumens

sq feet * lumens per square foot / lumen output of HPS = Number of HPS ballasts needed
144 * 7000 / 55000 = 18.33

For such a large scale project it is probably better to go with 600w HPS ballasts as they are more efficient lumens per watt than either the 400w or 1000w ballasts.

2 1000w on light movers will do the trick. Or if nothing else, I would get the light movers!

4 1000s or 3 if your gona keep the 2 400s

Dude - are your arms 6' long or do you plan on wasting your grow lights by lighting up the aisles with them? The point being, you can't work a space that big unless you know what you're doing! You obviousely don't, or you wouldn't be asking such a basic question.

Please take some advice - start small, study a lot, pay attention and learn from your mistakes. Once you get good at it, then, and only then, expand and go Big Time!

lol trust me i know how to grow some nice bud all im asking is how much more light i would need as i didnt know how much mine put out.