Quote Originally Posted by stra8outtaWeed
Lumens and Lux are measurements of how bright a light source appears to the human eye. Since the human eye is most sensitive to colors plants don't need, and least sensitive to colors plants prefer, Lumens can't be used to accurately compare the plant growing capability grow lights.
If a grow light manufacturer rates his grow light output in Lumens they are only telling you how bright it will appear to you and light your room, not how well it will grow your plants. The most accurate unit of measurement for comparing plant lighting is the micro Einstein, which measures how many photons of light strike an area per second.

But, while this is a much better way to estimate a lamp's plant growing ability than Lumens or Lux, it is still very difficult to directly compare two different types of grow lights. All grow lights except the LEDs grow lights emit large amounts of light plants don't use very efficiently, so including that light output in a light's plant growing measurement is misleading.

:thumbsup:
Very cool ! Thanks for all the info!