I just thought I'd drop by and say that there are some HUGE misconceptions behind
led.
Disclaimer: I do this professionally across the globe. Not just lighting, but full crop production systems that feed small countries. This includes producing certain grass crops using ZERO LIGHT at all for livestock fodder.
The majority of plants do not react along certain wavelengths, and this can be verified with a simple CO2/O2 exchangemeasurements or via protein fluorescence observations.
In fact, a majority of non-woody plants will have adverse reactions to exposure to green light, such as stunted growth or hindered reproduction. Trees, on the other hand, need green light to fulfill their full reproductive cycle properly.
Most simple vegetative crops, such as lettuces, basils, spinach, celery, do well with a mix of three or four wavelengths of light from the red and blue range. Most fruiting crops have shown similar results, like tomatoes and peppers, and strawberries.
You can get similar results by buying true primary-color T5HO
bulbs, they do make pure 460nm and 630/660nm tubes but they get expensive, almost as expensive as LED, although the price of LED is dropping rapidly.
Don't be fooled by more bands = better results. That's simply unfounded. I have a tri-band 50w panel, and the same panel using quad band + 4500K white. The tri-band had the EXACT SAME PERFORMANCE as the quad-band when it came to the test crops of everbearing strawberries and spinach. I've seen dichromatic panels perform similarly.
The fact is, in the visible range, there are four wavelengths that are the most active. Trying to stimulate phycocyanin and phycoerythrin is pointless as that is primarily found in marine flora, not land flora. Just recently, a bacterium with a chlorophyll that could directly power photosynthesis with IR light (which we previously thought impossible) was discovered, but again, it's only in that bacterium - expect everyone to start unfoundedly saying "Stimulates Chlorophyll F!" with their sudden addition of IR to their panels. In fact there still isn't any real solid published Emerson Effect evidence. Ther's a bunch of conjecture and speculation, but not one single double-blind experiment conducted.
Colored CFLs aren't going to work well. You're losing light output with a filter instead of converting all possible energy into the wavelength desired, and you can't even guaranteed that colored filter is allowing the desired wavelengths through.
To address one statement made:
"But the light intensity from even these High intensity LED's are no match whatsoever to the light intensity of MH and
hps."
I'm bleaching plants from 18 inches away with a 300w panel using true 3w diodes. 2,000umol+ intensity (that's sunlight intensity) from a foot away, unlensed, smashing the outputs of a 400w CMH. If you want to go by the latest, Cree's about to drop a 200+ lux/w white diode out. Currently, we've got 150+ (but that doesn't matter, photon flux density in certain wavelengths matters.)
Also, most LED panels are using research from the 90s, and specifications from the 90s. that 7:1:1 (or similar) ratio is just GARBAGE. It's fine for vegetative plants but for producing fruits and flowers you MUST have more blue for bulk mass production, as it's the higher-energy blue photons responsible for the majority of biomass production. All that red does nothing without the right balance of blue to match!
http://i.imgur.com/j9GP1.jpg
That's a pic of me in the UK research facility. Loose Leaf lettuce, 8 days from seed, testing various ranges/combos of reds and blues.
Oh, for fun, I can also produce certain crop types without light at all (not talking white asparagus or endive, we're talking green grass for livestock.)
http://i.imgur.com/woDrp.jpg
Like that.