Courtesy of Brandon Bailey, Conscious Creations
Cannabis cultivators are always striving to give plants what they need to grow their best, sometimes pushing for greater yields, sometimes improved quality, and sometimes both.
For growers producing flower, achieving greater consistency in the size, compounds and density of buds has been top of mind to give consumers and patients a reliable, elevated experience.
Commercial cannabis cultivation at scale, while increasingly sophisticated, is relatively uncharted territory, so this often involves trials and tinkering. One aspect of cultivation that seems to intrigue growers most is light, as it is arguably the most crucial input in greenhouse and indoor facilities.
Cannabis plants can endure significant light, but there is still a point of diminishing returns with top fixtures which is why many are exploring intercanopy light to help illuminate parts of the plant that are generally shaded and end up developing into lower grade buds and trim, says Dr. David Hawley, principal scientist at Fluence.
By bringing light to lower branches, areas of the plant that produced lighter flower are suddenly denser and more productive, resulting in more consistent, high-quality A and B buds, Hawley says.
“When it comes to intercanopy lighting, that tends to be where it shines strongest, if you forgive the pun, because we see a lot of folks saying, use intercanopy light and it's going to increase your yields and make all these positive changes in your life,” Hawley says. “The reality is cannabis can tolerate so much light that if you are adding light to the crop, whether as top light, whether you're adding it as intercanopy light, generally you'll see a fairly similar response if you're adding the same amount of light. There is potential in some cases where using intercanopy light instead of top light may be more beneficial for yield. But really, it's that quality and consistency factor that is much more receptive to intercanopy than top.”
LightSky Case Study
Fluence has partnerships with growers nationwide to test and trial products. Michigan-based indoor cultivator LightSky Farms was a good candidate for an intercanopy lighting trial, says Dr. Jason Matlock, Data Science & Communication Specialist at Fluence, because they were looking for ways they could enhance their already solid cultivation practices. Launched in 2013, LightSky operates an 85,000-square-foot cultivation facility based in Burton, Mich.
“They operate at a reasonably large scale for a single-state operator, but their absolute brand model is around the quality of the product that they produce,” Matlock says. “I said, ‘I’d love to vet this technology, can we get it up and rolling?’ And they said yes. They have a [research and development] space that they largely use for pheno-hunting and genetic screening, but they said, ‘Hey, we can set aside some space in this R&D room.”
LightSky, which has worked with Fluence for six years, installed the company’s VYNE lights along two, 4-by-8-foot benches, and trialed two different lighting concepts: the group of plants on bench one received a photosynthetic photon flux density (PPFD) of 1200 micromoles of photons per meter per second (µmol/m2/s) from the company’s VYPER top lights only. The second group of plants on bench two received the same amount of light, 1200 µmol/m2/s, but about 900 µmol/m2/s was from top lighting, while 300 µmol/m2/s was from intercanopy (ICL) VYNE lights. They trialed the lights through two, nine-week flower rotations on three cultivars, Matlock says.
The biggest takeaway from the grower case study was that Light Sky was able to produce more high quality, A grade flower with the intercanopy lighting treatment, and that there was more uniformity in bud size throughout the plants, Matlock says. Trim-to-bud ratios were also reduced.
“And they did a lot of data collection with us. Not only did we look at the traditional yield of A [treatment] versus B, but we actually got out there and took individual bud level measurements, size, density, potency to track uniformity of the crop and to look at quality metrics as well,” Matlock says. “What we saw was that we decreased variability at bud level. And so in ICL compared totoplight, we saw that bud mass varied less across the plant. You have a more consistent product, and that consistency is manifesting itself in these larger, high value bins.”
“LightSky’s emphasis on quality was key and the fact that in the Michigan market, quality of product is a market distinguisher,” Matlock adds. “We were looking for a place where that was going to matter, not only to the end customer, but also to the grower.”
Key Findings From ICL Trials
So far, Fluence has conducted five trials with three indoor and two greenhouse commercial cultivators, testing intercanopy light treatments using VYNE fixtures on seven cultivars.
With top lighting alone, across the five facilities, on average, 46% of the harvest was A-grade flower, 24% B-grade flower and 30% trim, Matlock says.
But when applying ICL, the average shifted so that 55% of the harvest was A-grade bud, and there was a reduction in overall trim, Matlock says.
“We saw that bud size varied less, and that's by roughly a 14% reduction in variability, 10% reduction in variability in size, and even in potency, we saw that there was less variability in the THC from bud to bud,” he says. “You're going to produce more of the high value product in a flower-driven market and less trim and B grade, so your total harvest market value goes up.”
GENERAL TRENDS IN ICL DATA
Research includes 5 facilities, 3 indoor, 2 greenhouse and 7 cultivars
Key Findings: 20% increase in "A" bud fraction; 25% decrease in waste trim fraction; increased homogeneity in bud mass, size and THC content. Data/charts courtesy of Fluence.
Increases in A-grade flower can translate into more profitability for growers, but importantly, reducing trim can also save on labor costs.
“We're interested in seeing if bringing light into the canopy can help reduce the amount of work potentially that goes into managing that canopy,” Matlock says. “A lot of the labor that goes into cannabis, which is a substantial part of its cost, is managing canopy to get light to those lower buds. If we [add] light there, perhaps we can reduce that effort while still preserving the quality of the product and hopefully reduce the total cost of production by having fewer touches.”
Future Research
Most intercanopy lighting treatments Fluence has tested have split PPFD either with 75% from top lighting, 25% from intercanopy, or roughly two-thirds from top lighting and a third from intercanopy.
“It's easy to digest and easy to deploy for a lot of people, but the reality is that, again, cannabis just is the kind of crop where it can tolerate and thrive with so much light that your overall yield is going to be probably pretty similar regardless of how you divide up that ratio,” Hawley says. “For us, when we think about creating the most uniform light environment, given the evidence that we have so far, the more uniform we can induce that environment to be, the more uniform bud quality and yield you can achieve within the canopy.”
Fluence is also working with another cultivator who is testing the impact of ICL when PPFD is at its maximum output in top lighting, and more is added via intercanopy fixtures to see how plants perform.
“In that study, we specifically worked with a cultivar that developed unfavorably above 1250 PPFD. We added 200 to 300 PPFD of intercanopy lighting to the existing 1250 limit and achieved both yield and quality improvements,” Matlock says. “And the results actually suggest that we're able to push more flux [PPFD] and still see a yield response by putting it into the intercanopy than we could if we were just running top lights. So for those who are looking to really and truly squeeze every drop of blood out of that stone, ICL might also be a tool for that.”
Flower grown at LightSky's cultivation facility in Michigan. Photo courtesy of Brandon Bailey, Conscious Creations
Matlock and Hawley add that before trialing this or other ICL concepts, and certainly before deploying it facility-wide, that cultivators have a strong handle on crop steering and plant management.
“If you do apply that light a little bit more intelligently and down where the canopy maybe isn't working as hard, then there's more potential for the whole plant to continue thriving as photosynthesis is driven harder, but all of those other ancillary functions like carbon translocation--moving from source tissues like leaves to sink tissues, which are buds – all of that [must] keep up and be maintained so you get a better plant behavior overall,” Hawley says. “If you take light and you add it down in this lower canopy that's otherwise quite shadowy, you can enhance photosynthesis in a part of the canopy that can utilize it better than the upper canopy that might be close to photosynthetic saturation. This can enhance yield to be much better than if you were to just add more top light.”
And, Matlock points out, even if your yield is the same, ICL can still generate more A-grade flower, which can result in more successful harvests.
“Even if you're yielding the same mass, from an economic standpoint, you are yielding more because you're gaining more of the plant that is worth more money,” he says. “This is something that's interesting about the cannabis space. In commercial agriculture, we almost always talk about economic yield and economic thresholds. There are always ways of pushing more yield, but they don’t matter if they don't pay for themselves and produce an economic return. In cannabis, we tend to focus mostly on the actual physical yields and numbers instead of the net economics. ICL makes a lot of sense from an economic standpoint because it’s allowing you to turn more of a single fixed harvest into something that is valuable."
Tips for ICL Implementation
For growers who are considering adding intercanopy lighting, the first thing to confirm is that the environment is stable and growers are able to properly steer as needed,” Matlock says.
“You need to already have good environmental management practices in place. You probably won't see a benefit if your crop is chock full of leaves and you're not getting any air into the center of the canopy,” he says. “If there's no carbon dioxide to feed photosynthesis, it doesn't matter if you add light because you don't have the other pieces of the puzzle in the place.”
Additional circuitry to power the fixtures is also usually required, Matlock says.
“It's usually going to be separate from your existing lighting circuits because they're almost always maxed out,” Matlock says. “And while ICL fixtures don't take up a lot of power[relative to top light], it's still not small, and they need to be independently controlled.”
Generally, ICL is deployed in week three in flower, he says, when flowering sites are starting to develop. There are a variety of ways they can be installed, which is one of the unique challenges of intercanopy lighting, as bench and rack systems aren’t standard. Generally, a custom solution is needed, Matlock says, and he’s seen “the ingenuity of growers” really shine in this area.
“Every grower has slightly different infrastructure that they're solving for,” Hawley says. “Having said that, we have a couple solutions using off-the-shelf parts that we've developed and tested in-house with tension cable … or a few other things. We've produced a couple short videos showing how we've done it. If someone wants some help getting started, we can show them those videos and we can chat with them and understand their infrastructure and help them find a solution.”
Many growers who worked with high-pressure sodium fixtures and transitioned to light-emitting diodes (LEDs) probably remember the environmental shifts and adjustments needed to support the new technology. Though implementing intercanopy lighting is, by comparison, a relatively small change, there are still things to keep in mind.
“You do get about a two-and-a-half degree Fahrenheit increase in your canopy temperature,” Matlock says. “In most cases, that's actually not a bad thing because you had to have a lot of heat up at the top of the canopy and the intercanopy space gets a little cool. By raising that temperature up, you're increasing the water holding capacity of the air and actually reducing susceptibility to mold and mildew. So in many ways that's kind of helpful.”
Although the Fluence team hypothesized yield and overall flower consistency would improve with intercanopy lighting, they were still surprised at just how compelling the results from LightSky were and are looking forward to exploring more.
“We broke the boundary with their cultivars, and we improved [LightSky’s] trim fraction, which there wasn't much to reduce to begin with,” Matlock says. “I mean, every one of those things looked like they belonged in a bag. So, I was really surprised. While VYNE can help some people solve some operational challenges and put more on the table, particularly if they have moderate top light environments, it is very much a viable tool for the person who is already excellent and is looking to further that limit.”
