Quote:
Originally Posted by 3rdMaestro
I too have heard that the ratio of red and blue plays a difference. But my one concern was more along the lines of; if I took 2 of the same orchid and grew them for 3 years, one under full spectrum t5s and one under blurple lights of the same light output, at the end of the 3 years, would the 2 plants look pretty similar in growth? Or could you tell that one has been growing distinctly different than the other?
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Sounds like a worthy experiment. Go for it, take one for the team and let us know in 3 years
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Who really knows what the optimum spectrum and quantum efficiency is best for a plant? I think the best we can do is determine what other scientists have already assessed ~ e.g., McCree ~ who have already researched and recorded the rate of plant growth to each wavelength [color] of light. Then we can use that information to see what works best for our plants.
Just an opinion for what it's worth - regardless of spectrum, artificial light will never match natural sunlight. I am an indoor grower. I do not have access to the sunlight I would like to have (for growing my plants). I depend on artificial lighting. Throughout the years I have used incandescent, fluorescent, compact fluorescent. HPS, MH, and LEDs. All varied with spectrum and intensity, and they all grew plants differently.
My lighting emitters of choice (now a days) are LEDs. I like having the option of building my own fixtures and being able to tweak the spectrum of my lights (because an ideal spectrum will be different by species, especially during early/later growth). To produce a well balanced spectrum for growing my various species of orchids, I use a combination of red/green/blue and white diodes. When I say red/green/blue, they have different nanometer wavelength ranges (i.e., royal blue 445nm, cyan 495nm, lime green 567nm. deep red 660nm, far red 730nm, and whites with different kelvin temperatures 5,000k & 6500K).
The combination of colors I use have been favorable for growing all of my orchids. But (very important to me), this combination produces a white colored light that is also very pleasing to "my" eye. I like the appearance of a white colored light and really dislike looking at a burple colored light. Of course I think we all know full spectrum light is a broad band of the light spectrum, and red/blue light emits a narrow band of the light spectrum. Photosynthesis has been proven to peak in the red & blue wavelengths. Are other wavelengths beneficial for photosynthesis and/or the overall growth of a plant? Sure they are!
NASA did several in-depth studies years ago, in regards to the use of red/blue lights for growing plants. They found that this combination (especially with a higher percentage of red to blue) was optimum for growing the plants they were working with. Elongation and compaction have been brought up already about the use of red and blue by others who have posted in this thread.
Red and blue have the highest photon *efficacy* compared to other colors. Where does this come into play? Money, honey! If red and blue are efficient/optimal for photosynthesis ~and~ have the highest photon efficacy compared to other colors, it makes "cents" (sense). Dollars spent on electricity to produce those photons is a big energy cost savings. Again, just my opinion.