lighting sq ft?

Hi All, I am working on my lighting and have a question on calculating amounts needed. When you measure out a room's sq footage to calculate the amount of light you need do you just measure the sq footage or do you measure cubic feet?

Sq. ftg. of floor space to be used .
Most ppl. shoot for 50 watts per sq ft btw.
Crispi :stoned:

so if you have a 4x4 area that would be 16 sq ft ? and then 16x50=800 watts
would this be correct ? Luna if you are planning a all indoor grow?If so you definately might want too plan two grow areas(as I am finding out for myself) one for veg and one for flower it makes life so much easier and you can have meds all the time, not large amounts but enough for personel use I am planing two 4x4 areas or close too that, maybe a 2x4 and 4x4 :hippy:

Thanks guys! You should have seen the number of bulbs I had come with when I was calculating cubic feet!(G)

Veggi, I have a thing about a grow completely inside. Except for the bathroom all our floors are hardwood and carpet I know I could never be careful enough. I was going to even had it all planned out and then chickened out and am planning an enclosed balcony grow. I am also trying an autoflowering strain my plan is that during spring and summer I grow outside and the rest of the year smaller autoflowering crops that way I'll never have to stress that I'll run out every year.