Guide To LED Grow Lights: Spectrum & Wavelength
Posted by Irish | Posted in LED Growing Guides | Posted on 15-09-2011
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As LED grow lights increase in popularity, manufacturers and distributors are searching for new ways to attract the attention of various customers. The majority of manufacturing companies seem to take pleasure in adding innovative marketing ploys to scientific facts in anticipation that consumers will pause for a few moments to become mesmerized with the latest hyperbole. There is a considerable number of phrases that find their way to customers’ ears all around the world, making it hard to distinguish marketing hype from reality.
A commonly used marketing method embraced by many companies and manufacturers in an attempt to acquire the attentions of potential customers is to discuss the wavelength and spectrum of the LED grow lights they market. Below is an easy to understand explanation of what is important and what is not regarding the use of LED grow lights:
Facts About Light Spectrum
To gain a thorough knowledge of light, a person must fully understand word “spectrum.” This word essentially means the visible light wave length range in its entirety. Aside from visible light, the full electromagnetic spectrum includes energy in the form of radiation from sources such as microwaves, radios, infrared rays, ultraviolet rays, X-rays and gamma rays. Many people are unaware of the fact that the plural form of the word spectrum is “spectra” not the more often heard “spectrums.”
However, moving along, grow lights are essentially concerned with the spectrum that is visible, although sometimes they also utilize both the infrared and ultra violet spectra.
Understanding Wavelength
Regarding an LED or other type of grow light, the word “wavelength” refers to the distance between the peaks and troughs in a wave. Light wavelength acts in a similar way to water waves, where the peaks and waves can be a good length apart or very close together depending on a variety of factors. This is what makes a person see one color as opposed to another. Red shade are produced from long wavelengths, while blue colors come from short wavelengths. Nanometers are used to measure each color within the spectrum ranging from 380nm to 780nm from blue/violet to red respectively.
Plants obtain all their energy needs for the process of photosynthesis from the visible light spectrum. The aforementioned LED lights were produced based on this occurrence in nature, which was researched by scientists and botanists.
How Plant Growth is Encouraged With LED Grow Lights
For substances such as high pressure sodium, HID lights attract a specific end of the red/yellow light spectrum. In general terms, plants respond to all light in a similar way to all light; however, most of the benefits received by the plants come from numerous blue and red wavelengths. This essentially means that they receive the smallest amount of benefits from greens and yellows, as most of this light is reflected back to the original place from which it came.
Initially, producers of LED lights believed that one band of blue light and a single band of red light were all that was needed, and if growth conditions were suitable, success could be obtained. Although this might have worked on botanical life such as grass under specific testing conditions, it failed completely or produced negative results in more complex plants such as those that grow on a vine like tomatoes. Nevertheless, companies did not cease to manufacture badly designed LED grow lights in the initial production period. For this reason numerous production companies are still attempting to distance themselves from this stigma.
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Essential Spectra and Wavelengths for LED Grow Lights
The manufacturers who embraced LED technologies early on, knew there was plenty of potential in some of the new discoveries, and fortunately for consumers they continued to encouraging further LED technology development. After a short amount of time, they found that the early models were partly successful and they had a good grasp of the red-blue light concept. However, there were still details to be considered. It was discovered that more wavelengths were needed to address the problems associated with the early LED models. When one views a PAR chart, he or she can easily see that there are distinct areas on the light spectrum where botanical life obtains practically all of the energy they needed for photosynthesis. In addition, further tests showed that two distinct peaks in both the blue and red spectra and one specific, smaller peak in the orange spectra were present, proving that three light spectra are required for a total of five wavelength–light bands.
The above scenario basically means that the LED grow light is ideal for the entire plant growing cycle; from flowering to vegetative growth. In simple terms, light from the blue end of the spectrum is necessary for plant growth, and results in strong healthy plants that produce thick foliage. Simialrly, red and orange lights are necessary for flowering and fruits, and the growth of large dense, buds on all the nodes which were created in part by blue light.
The Future of LED Grow Lights
Although certain production companies are still heavily marketing and advertising their full spectrum lights and numerous LED models, other manufacturers are opting instead to use today’s modern refined technology. Certain companies and individuals believe that the primary purpose of LED grow lights is their efficient function and production of precise wavelengths needed for the process of photosynthesis. The majority of people know that the full spectrum that HID lights produce are not efficient, even though certain manufacturers still push such models. In addition, adding excessive LED bands which only serve to give more light that is not really efficient anyway is considered by some people to be a step backward instead of forward.
There is no one who has exact knowledge of what the future holds for LED grow lights, but certain manufacturers do a better production job with such lights because they choose better and more efficient technology. Fortunately, it is known that the scientific research now being conducted will benefit the industry for many coming years.