Demystifying Light Levels for Cannabis Grows
As more and more investors, opportunists and growers are jumping onto the green rush that is the cannabis industry right now there is also a big influx of folks who are learning as they go. Lighting is a major purchase for this industry as a big margin of growers still prefer the better climate control and security of growing indoors and even those who choose to grow in a greenhouse are finding that no matter where they are in the world, they still need to supplement lighting to continue producing a high-quality product year-round!
There is a lot of information flooding this industry when it comes to what types of lights to use – HPS, MH, LED, etc. – as well as which spectrum of these lights will work best. While this part of the horticultural lighting industry is still in its infancy when it comes to actual, quantifiable data that PL Lighting and other companies are in the process of gathering there is one part of this data that we do know. That is what light level or how much light is needed for a crop. Light source choices can come down to costs of electricity, municipality rebates or incentives and even heating and cooling costs, so what is right for you may not be right for others. This is not the case with the amount of light and is the topic I want to discuss here.
As “The Lighting Knowledge Company” PL Light strives to be your source of information to help weed through the bombardment of info you can find on line and especially when researching lighting for cannabis. First, let’s discuss the correct unit of measurement for lighting a crop. This would be moles. In the US the more common forms of measuring light are lux and foot candles but these units are an instantaneous measurement of the intensity of light that is visible to the human eye – mostly between 500-600 nanometers. For crops, photosynthesis happens using a broader spectrum of light wavelengths referred to as PAR (Photosynthetic Active Radiation) which is the range from 400 to 700 nanometers and actually drives photosynthesis. The measurement of the mole is the amount of actual photons over a square meter over a period of time (photo period).