[antisthenes]

Because at least Red LEDs generally aren't more efficient than CFLs.

You can find tons of articles claiming some lm/w record being achieved in a lab of 110 lm/w, 200 lm/w and other ridiculous numbers, but the reality is most of consumer grade available LEDs will only be 10-30% more efficient than a CFL, and probably _less_ efficient than a t5 fluorescent tube.

I've looked into this extensively when running an indoor garden, and in the end decided to go with FL tubes and a 400W HPS (which was far better than any LED on the market in 2010)

[legulere]

lumen are defined by visibility for the human eye, which is not what you are optimizing for when growing plants.

[hultner]

What was on the market 2010 is significally different from what is available today, progression in this field have been huge during last few years.