I havn't tested this yet... but i have an idea.
Most grow lights with full spectrum etc, consist of white leds, red leds and blue leds. Problem is that blue and red leds are quite inefficient. The red and blue led technology is ~2-3 years old. White leds are getting increasingly more efficient. And when you look at the spectrum of the different cold white, natural white and warm white leds, they atually look quite decent, with continuous spectrums that are not too far off compared to the photosynthetic absorption spectrum. The most efficient led atm is the Cree XP-L led which produces on average 122.6 Lumens/watt at 85 degC. However they are quite expensive.
I've compiled an image by overlaying a HPS spectrum, led spectrums and the photosynthesis spectrum in word so...erh..yeah. Needless to say its not that pretty.
But you get the point i think. If not, the point is: Natural white led's win. In my opinion...
The rainbow colored spectrum corresponds to HPS. The blue, green and red lines correspond to cold white, natural white and warm white Cree XP-G2 leds, and the dark green dashed line corresponds to the photosynthesis absorption spectrum.
Another point to make is that the so-called penetration depth (of light
) depends on the light intensity. The closer a given set of leds come to eachother, the higher the intensity.
So my claim is: Multi-chip led lights composed of new efficient natural white leds, will outperform those led grow light panels of similar wattage for the reasons stated above, and re-iterated here below:
1: more lumens / watt
2: higher intensity
3: better or similar spectrum
edit: another point to add:
4: cheaper .....edit2(i mean, cheaper than grow light)
I just recently bought such a led light. I have not recieved or tested it yet, and i can find no "grow test" of it anywhere, so it might be a very bold claim to make. In any case, i think its worth a test.
Cheers
