Quote Originally Posted by Zandor
The magic number is 50 watts per sqft. More light equals more buds and light from the top and light on all sides will grow more bud then just one light above. The problem with top only lighting is penetration to the lower branches. With top lighting only you will only get bud from the top 1/3 to 1/2 of the plant.

Yes 400w is fine for 2 plants. Use Mylar on your walls to increase the light to the lower branches it does help.
Maybe you can help me decide on some lighting connsidering the factors
120 square foot room I was planning 1000 watt MH and 1000 watt hps from what you just explained would I do better breaking them down into several smaller watt lamps ? What might you suggest the best lighting arrangement ? thanks Bill Thick