What You Need To Know About LED Lighting Recipes

by | Oct 20, 2017

Written by Jessica McKeil

Jessica McKeil is a cannabis writer and B2B content marketer living in British Columbia, Canada. Her focus on cannabis tech, scientific breakthroughs, and extraction has led to bylines with Cannabis & Tech Today, Terpenes and Testing, Analytical Cannabis, and Grow Mag among others. She is the owner and lead-writer of Sea to Sky Content, which provides content and strategy to the industry’s biggest brands.

|Long gone are the days of growing cannabis with a simple on-off light switch and a manually managed light schedule. Large-scale commercial operations rely on much more than intuition these days; using high-tech mobile apps for remote management and in-depth analysis of historical light information. |

In fact, growers are now using technology to learn intimate details about the light requirements of specific strains and then making minute adjustments to produce individualized LED light recipes that their forefathers could only dream about.   The science of light has gotten a lot more complicated in recent years, thanks in part to the continued drive of cannabis growers to increase yields of their indoor operations. No longer are indoor facilities installed with lights built strictly for the benefit of human eyes; these days LED lights focus entirely on benefits for the plant.

Energy monitoring and instant access to historical data allow companies to predict expenditures and accurately predict crop yields. Many advanced LED lighting solutions, such as through Cortex, allow for automated scheduling and the ability to partition different crops areas onto different light schedules.

|Evolving Science Around LED Light Recipes|

Light science has been around for decades but mainly applied to urban indoor vegetable farms. This research has moved beyond the development of leafy, green lettuces and is now focused on the booming cannabis market. The ultimate goal of marijuana producers is to improve cannabis biomass during the flowering stage. Growers discovered long ago that the spectrum of light that works for high-yield micro green operations requires alteration to fit the marijuana natural growth cycle.


Courtesy of Yuji International

Image courtesy of Yugi International

Even in recent years, the science around the light spectrum requirements of cannabis has shifted. The comparatively older science focused strictly on laboratory results. This meant scientists examined what was happening in a test tube instead of in the grow room. Researchers had discovered that blue and red spectrum lights (often combined and referred to as the purple haze) triggered peak chlorophyll absorption in the laboratory. At the same time, they found that green light had little to no effect on growth cycles.

Quickly this recipe was adopted industry-wide by indoor marijuana growers. Everyone abandoned non-efficient, non-LED lighting systems to cover their crops with a deep purple haze. White light was abandoned altogether in some cases. Through the installation of LEDs, issues with heat and wasted energy disappeared overnight.

|Current Focus on Full Spectrum Light|

Over the last few years, the strict purple focus has proven a bit problematic. Horticulturalists have realized there is much more to learn about how the entire spectrum of light affects the cannabis growth cycle. There is a complex synergy to providing the full range of light (also called white light) to plants. Full spectrum has exponentially more to offer than a combination of one or two of its different parts.

Indoor growers are striving to make small adjustments, to reap powerful benefits. A small change in light during the growing process can potentially produce a significant reward. Even a one percent increase in yield by a large-scale marijuana operation could mean huge payoffs.

Each and every strain will react differently to light. Therefore the development of a perfect light recipe requires rigorous, time-consuming experimentation. For example, by investigating a single variety of strawberry for over a year, making slight adjustments to the light recipe during every harvest, Gus van der Feltz, global director of city farming at Philips Lighting, was able to increase harvest yields by 20 percent.  At the same time, they were able to develop a much juicier and flavorful berry.

Like the juicy strawberry experiment, growers are tinkering with light recipes during the standard eight-week cannabis growth cycle to explore the change in terpene development. They are also testing for what light triggers which cannabinoids to develop.  This has enormous potential for the explosive cannabinoid isolate market.

Preferred combinations of light now typically include red, far-red, blue and white light. It should also be noted that incorporating other light, including green, may help produce other characteristics, including terpene development. In another example, some lettuce producers have noticed that green light stimulates a deeper green in their leafy heads of lettuce. It is thought that different light, presented to the plants at different times, may favor different hue development in cannabis.

The old red, blue and purple focused lighting strategies, while partially beneficial to biomass development, are detrimental to human activity. Many growers and greenhouse workers complain of headaches and eyestrain when working under this restricted spectrum. Instead, companies are encouraged to use lighting systems such as Illumitex LEDs, which have pre-set light recipes perfectly suited to safe human activity.



The new trend is towards LED lighting systems which are controlled easily and remotely. The market is becoming extremely competitive, with each company striving to gain even minuscule improvements over the competition. This push has lead to creative experimentation with light technology. The software to program specific light recipes is now easy enough for even non-techie growers to play around with and most importantly to learn from.

The efficiency and cool temperatures afforded through improved LED fixtures, allows growers to focus more on adjustments to the recipe instead of the bottom line. Tweaks to complex LED light recipes has allowed for the development of lush, dense biomass even when all other factors remain the same. Every strain has the potential to become something great when given the correct dose at the right time during their growth cycle. The future of light science for cannabis growers is bright.