For a fairly small grow cab situation (no bigger floor area than 2' x 3', or possibly 2.5' x 2.5'), I was debating which would be the best use of light, considering...

- I don't want a lot of noise
- I want to use as little power as possible
- I have no immediate plans for C02 enrichment.

As such, I'd like the lights to give adequate light per square foot, but not generate unnecessary heat (necessitating further climate control measures, hence more noise and more power consumption.)

I also realize that the further a light is from the plant itself, the less lumens the plant is receiving. If lumens are measured 1' from the light over a 1' square area, then a "larger" single light above the center of the garden is going to give the most light in the center, less so as you go outward. Further, I'm aware that the lumen value listed in the manufacturing details drops after you go 1' away.

Given this, and my desire for a consistent crop (both in terms of quality and height) in a Sea-of-Green cabinet set up, I was thinking - wouldn't I be better served by running several smaller wattage HPS lights, instead of one larger one? The way I'm figuring this, it could very well wind up involving the use of less power per harvest for more actual lighting.

Judging from my energy bills and the 1000kwh price, even the price of bulbs over the crop's lifetime would not put me over (since replacing one say, 400w bulb is cheaper than replacing 6 x 50w bulbs in a 2' x 3' area.) In theory at least, I should also be able to place these bulbs closer to the plants than a single larger light, thus increasing efficiency.

I've read that 2000 lumens per ft/sq. is the absolute least I would want to go with. Some say 2500 is the healthy minimum. However I've also read that over 3000 lumens per square ft. is only good if you have everything else keyed in, including the proper use of C02 enrichment.

So is my thinking correct...would 6 x 50w HPS be better for my situation than a single 400w bulb? It would also seem to ACTUALLY match up to the talk of "50w per square foot" which many grow FAQ's mention (where as it would seem a larger single light solution would not, at least not for outlying plants in the garden.)

On paper this sounds good, based on everything I've read. Am I missing something though? I guess the real clincher is if I can in fact keep a 50w HPS bulb (1900-2200k) 12" away (or just a bit more if need be) from the plant tops? Would that be possible with reasonable ventilation (but nothing too heavy duty), or would that be still likely to burn the plants?

I'm just very skeptical that "a big friggin' light" is always a good thing. I'm just interested in keeping a regular stash on hand, with some to spare (will personally smoke 1/2 oz. a week, tops...I mean, that's if I have a lot of free time on my hands.)
sharer6969 Reviewed by sharer6969 on . Lumens and number of lights For a fairly small grow cab situation (no bigger floor area than 2' x 3', or possibly 2.5' x 2.5'), I was debating which would be the best use of light, considering... - I don't want a lot of noise - I want to use as little power as possible - I have no immediate plans for C02 enrichment. As such, I'd like the lights to give adequate light per square foot, but not generate unnecessary heat (necessitating further climate control measures, hence more noise and more power consumption.) Rating: 5