The first step to my new garden idea is generating light. When I first considered hydroponic gardening I never gave much consideration to the different options. After hearing in biochemistry class that chlorophyll, the photosynthetic pigment in plants responsible for their green color, only absorbs certain wavelengths of light I was sold on the concept of LEDs.
First a little history of the LED. I’ve always enjoyed LEDs ever since I was little. I remember learning about them from those electronic kits that allow you to build all kinds of devices and circuits. The first thing that I learned, and am constantly correcting people about, is that they are not little tiny “bulbs.” LED is an acronym for Light Emitting Diode. A diode is an electronic gate which allows electricity to only flow in one direction. These special guys produce light. Over the years there has been a tremendous amount of technology in the LED department. Several new colors have been made possible expanding the selection from the standard green and red. When white LEDs were finally produced there was a big discussion in the art department on whether or not they should be used in lighting paintings because the white wasn’t true white. The early whites contained a lot of blue but more true whites have been developed since then. Infrared LEDs are ubiquitously used in remote controls for all electronics from televisions, stereos, fans, and even RC cars whose range is limited to the beam of invisible light. Ultraviolet LEDs have been produced as well. LEDs generally use very little electricity and for that reason are excellent for many applications. There are a few very bright LEDs manufactured by Luxeon known as the Star. They are extremely bright and can even be made for 5 watts a piece! They get so hot they require a heat sink to keep them cool enough for operation.
Now that you know all you didn’t care to know about LEDs you can see why I chose them for my garden. They use tremendously less electricity than other forms of artificial light and they can produce the exact colors or wavelengths used for photosynthesis. As I said before chlorophyll is the green pigment in plants and only uses certain wavelengths. It operates by two mechanisms known as photosystem 1 and 2. The two most common photosynthetic pigments in plants are chlorophyll A and B. They absorb and utilize wavelengths of 400-450 nanometers and 650-700 nm (chlorophyll A) and 450-500 nm and 600-650 nm (chlorophyll B). These wavelengths correspond to violet-blue and reddish orange-red. So why waste electricity producing colors you’re not even using? Why not just use red and blue lights? Yes! The LED lighting system. Now that’s not to say that plants don’t use other colors of light as well, it’s only chlorophyll that uses the frequencies listed. Plants use other photosynthetic pigments known as accessory pigments such as xanthophylls, and carotenoids which absorb other frequencies. Other photosynthetic organisms such as algae and bacteria have an even broader array of photosynthetic pigments.
So now that I’m only spending money producing the wavelengths of light I want at a very efficient rate where do I get the grow lights? Ebay! There are other websites where you can purchase these directly though their manufacturers as some people shun ebay, but you will be overcharged at these places. The same products as well as the same companies are selling their stock on ebay for up to a quarter of the price in some instances. They have designs from 5mm LEDs to 10mm LEDs and higher wattage outputs. I’ll be sticking with the standard 14 watt panels that consist of 225 LEDs (165 red and 60 blue). Each panel costs around $20-35 depending on whether you buy them individually, in a bundle, buy it now, or auction.
Is this tailored light better for all plants? I’ve read that red light is generally better for flowering and fruiting plants which said to me that blue would be better for leafy greens. However, Japan says they grow hydroponic lettuce exclusively with red LEDs and produce crops in a third the normal growth time in soil under the sun. Blue light is known to trigger growth and in inhibit dormancy and stimulates phototropism which is the growth of a plant toward the source of the light. Red light has been know to trigger dormancy in some plants as well.
Even with the advantage of the specifically colored light I will be using in my indoor garden I will still have it located near a window so they can still receive the full spectrum of light to ensure their best health. Indoor plants like to have 16-18 hours of light in a day or 12-14 if they are supplemented with outdoor light. Grow lights are a must in an indoor garden, especially in the winter.