5000 lumens a sq. ft. will grow very well. Keep in mind that a 150w HPS or MH will put out around 13000-15000 lumens, and a 250w will be around 25,000 lumens. In other words, a 250 will do a terrific job in a 4 to 5 square foot area.

Having a ton of lights is okay if you have ventilation...but if (like most people) you have some problems there, don't overspend on lights. More light = more heat = more stress if you can't deal with the centing adequately. Get enough lights to do the job, use reflectors, and have good reflective surfaces (flat white paint or mylar) on the walls.
Roughrider Reviewed by Roughrider on . Picking out LIGHTS! alrighty, been a good while since ive attempted any kind of growing, and i am just curious, i am growing in a small space (not real sure how small yet cuz its at a friends) and i want to get the most light in as compact form as i can for as cheap as i can, i was thinking of going with 2ft fluoro tubes, any suggestions? Rating: 5