100W/sq.ft. is great, but the bottom line is 50W/sq.ft.
If you can get above that, you'll be 'in the zone'.
A smaller room should help a lot.

Weedhound, your math is wrong.
10x10 is 100 sq.ft.
1000W would only be 10W/sq.ft.

Baldyhippy...
Your 6x3 room is 18 sq.ft.
so you need at least 900W, so your 1000W would put you in 'the zone'.
psteve Reviewed by psteve on . growrooms x 2 questions? Hi Folks. In a bit of a delema here,Ive just cropped 12 plants wich were from clone and vegged for 3 weeks potted up along the way finishing in 6.5 litre pots. Theses where in a room sized 6foot x 6foot x7foot high so 36 square feet,under 1 600hps and 1 400 hps & I only managed an oz per plant..roughly! Now after some maths I realise where I went wrong yield wise..not enough light covering the floor space :thumbsup: All Ive got are the combined 600hps and 400hps and without Rating: 5