why ?

[phatsesh101]

why do we use square feet to measure light out put when sq. ft. is a two dimensional measurement? at the very least we shuold measure it in at least three dimensions being cubic feet considering they way unnatural light wanes in strength the further from the source it is. i suppose that square feet is a decent maesuement of sun light because lumenessence is the same on the ground as it is six feet above so you can say that the entire plant is getting an equivalent amount of light. whereas with a 1000w hps lamp the lumens fade the further you get. i read a post where the guy estimated 9000 some odd lumens per square foot but that only works if all parts of the plant are 26 inches from the bulb. but it doesnt work that way.

am i not getting somthing? is my idea flawed ?

phatsesh101 Reviewed by phatsesh101 on 04-05-2008. why ? why do we use square feet to measure light out put when sq. ft. is a two dimensional measurement? at the very least we shuold measure it in at least three dimensions being cubic feet considering they way unnatural light wanes in strength the further from the source it is. i suppose that square feet is a decent maesuement of sun light because lumenessence is the same on the ground as it is six feet above so you can say that the entire plant is getting an equivalent amount of light. whereas with Rating: 5

[TomStoner]

why do we use square feet to measure light out put when sq. ft. is a two dimensional measurement?

It's a rule of thumb and accurate enough for our needs, if you want to get serious about it you do need to think 3 dimensional about it and talk in par ratings rather than watts or lumens.