The types of LED grow lights range from blurple spectrum to adjustable spectrum to what’s referred to as full spectrum. They range in size and intensity. This article will assist you in making a fair comparison.
The Best Spectrum for Plant Growth
The bulk of scientific research to date emphasises that plants love blue and red wavelengths, particularly light in the photosynthetically active radiation part of the spectrum. More on PAR is available here. However, we still have a lot to learn about plant responses to different wavelengths. Also, there are benefits to using a more natural spectrum of light.
Plant responses exist that are not related to photosynthesis and more related to developmental growth. Those are photomorphogenesis responses. In other words, certain light wavelengths trigger photo receptors that are involved in photomorphogenesis responses. Therefore, a broad spectrum is likely the way to go. Another benefit to a broad spectrum is the ability to observe the plants in a more natural setting, making it easier to spot deficiencies.
Defining Full Spectrum
A full-spectrum LED grow light is simply a marketing term that implies that your grow light closely resembles light from the sun. This marketing term comes from the concept of full-spectrum light, which in recent years has been used to refer to electromagnetic radiation from the UV to infrared wavebands.
Differences in Full Spectrum LED Grow Lights
White light, or so called full spectrum light, consists of a combination of all visible light. Therefore, increasing part of the spectrum will change the composition of the white light.
A light that has a peak in the orange area will create a more orange look in the room.
UV and infrared spectrum
Far-red and infrared light has been proven to be beneficial to plants, most notably by Robert Emerson. More in infrared and the Emerson Effect can be found here.
On the other hand, the effects of additional UV light has not proven significant as of yet. Particularly when considering that the LED chips that emit light in the UV range are not very efficient. Also, the primary and secondary optics required for UV LED chips need to be very strong material due to the powerful wavelengths. Otherwise they they become brittle and really fast depreciation of light takes place. However, there are other ways to introduce UV, like lizard lamps.
Every manufacturer has a slightly different take on what they feel like is the optimal spectrum right now for plant growth.
Comparing LED Grow Lights and Manufacturers
A few key considerations when deciding to purchase any grow light are:
- A broad spectrum has numerous benefits over a limited spectrum grow light like blurple lights.
- Efficiency, or efficacy, is the most important factor to consider when comparing lights. Get the biggest productivity from the plant with the least amount of electricity going in.
- Third party testing of lights are important. Reputable growers, like MIGRO frequently test Mars-Hydro LED grow lights.
- Consider the quality of the fixtures and the availability of after sales service, like warranties.
- The availability of PPFD maps or charts is crucial.
References
- Lumigrow
- KIS Organics Cannabis Cultivation and Science Podcast Episode 48