3/11/11

Light, Photosynthesis and LED’s -- I


There is some confusion about LED’s so some background information on light to get started: The first step in photosynthesis (where light energy is converted to chemical energy for the plant to use to grow and flower etc.) is the absorption of light. Pigments are any substance that absorbs visible light. No pigment can absorb all types of visible light. Visible light is also called white light since all the colors of the rainbow (red, orange, yellow, green. blue and violet) together look white to our eyes. You can see these separate colors when white light passes through a prism. A prism separates white light into colors because each color is actually a type of energy with a slightly different wavelength and so each passes thought the prism differently and separates.

Ok, now that you have the background, Plants have many pigments but the most common one is called chlorophyll, it is what makes them green since all light accept green is absorbed by chlorophyll. The light absorption pattern of a pigment is called the absorption spectrum. The absorption spectrum is not the same for all colors, it has been shown since 1800’s and again many times that red and blue are absorbed more than other colors by chlorophyll. Now this is not the end of the story… the action spectrum is the relative effectiveness of different wavelengths (colors) to elicit specific processes such as flowering or phototropism (plant moving toward light). The similarity between the absorption spectrum and the action spectrum is evidence that specific pigments are responsible for that process.

Now here is where the confusion comes with LED’s. LED’s are very efficient light sources one reason being they emit light in a very narrow band (wavelength) Light wavelengths are measured in nanometers (a nanometer is one billionth of a meter- chop up a meter stick into 1 billion equal pieces). The confusion stems from the fact the pigments in our eyes are NOT the same as the pigments in plants. So, what we see as red or blue might not be the exact wavelength, measured in nm, that is going to elicited the maximum action spectrum for plants. In other words, just because an LED looks red or blue to your eyes does not mean it is the best wavelength of light for plant growth.

This is where HTGSupply.com has done their homework. The TriBand system has been created to generate light that is in the optimal range for absorption spectrum which will lead to the maximum action spectrum (This leads to maximum growth and flowering). Here is what you need to understand… Just because two LED’s look similar (have similar shape and design) does not mean they are the same. You can have two Corvettes that have two different engines and while they look the same, they certainly won’t drive the same. HTGSupply.com created their TriBand when they began consulting me, they wanted to make an LED that was the best for plant growth. I know they grow and test plants with all their lights, and so do I (Best LED LINK -- 2nd tested LED LINK). If you are not sure about growing with an LED, I can’t speak for any other company, but I can and have seen the TriBand lights grow plants from seed to flower and I have used it for cloning, this technology works.
Good Growing,
Dr. E.R. Myers

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