Photo courtesy Cannabis Research Coalition.
Travis Higginbotham spends a lot of time thinking about lighting, yields and energy efficiency — just like every cannabis grower.
But Higginbotham, the vice president of cultivation for StateHouse Holdings in California, is also armed with significant experience growing other plants, giving him a different viewpoint and some creative ways of thinking about production. StateHouse has been actively studying ways to increase efficiency by using intercanopy lighting — placing LEDs so they strategically shine light below or on the sides of cannabis plants — and the results have been impressive. His studies thus far have shown a 20% increase in yield and a 27% increase in the size of buds.
“I’m quite passionate about it, because the results just speak for themselves,” Higginbotham says. “This is a whole paradigm shift in how we design lighting for cannabis.”
Marijuana Venture: Can you give a background of the intercanopy study and what you were hoping to achieve?
Travis Higginbotham: Statehouse supports a few different university research groups. And there’s been a lot of research that supports cannabis continuing to push higher and higher yields at a DLI of 60 to 70 mol/m2/day, an amount of light that doesn’t touch the ground outdoors in the U.S. We’re talking about a plant that can tolerate being hammered with photons. That’s always been in the back of my mind: How can I optimize our production, knowing that is an incredibly strong driver to yield.
We also work closely with Bruce Bugbee (a professor of environmental plant physiology at Utah State University), and Mitch Westmoreland, a grad student of his, came out recently with a metric that was astounding: the flower on the cannabis plant alone contributes up to 30% of the total net photosynthesis of the plant. When I heard that metric, it really made me think differently about how to approach it from a lighting perspective. I come with being co-inventor of two patents in lighting and have a decent understanding of how all this works. That threw everything for a loop, to be honest, because I’ve grown plenty of other plants and you don’t try to target flowers — you’re targeting leaves. But cannabis flowers are green, therefore, they have chlorophyll and they photosynthesize, and Bugbee’s lab is showing that it can contribute to the productivity of the whole plant. Once I started thinking about this, we started to work with multiple different vendors on trialing it. This study was after we did two internal studies ourselves.
MV: How exactly was the intercanopy light redistributed?
Higginbotham: We worked with a vendor called Grow Light Design, and they created a square that fits an area like a traditional home grower would have. The reason I chose this fixture was because it was fixed on the benches, but unlike other light setups, I could still move my benches. And it applied light directly to the flower with two rows of lights that were right beneath the canopy.
MV: When you went through this process, did you expect the results to be that significant?
Higginbotham: Yeah, I did. There’s a metric that’s not discussed much in cannabis, but it’s used in other markets: photon conversion efficiency. This is defined on the unit of measure of grams per mol of light per meter squared, per unit of time (cycle or year). So grams per mol per meter squared per cycle.
This single metric shows how productive a grower is, not only with their utilization of energy, but how efficient they are at converting it to biomass. And then if you tie it to area and time, you can also judge in a single metric how efficient they are at turning their square footage annually.
This really starts to talk about productivity, while caring about sustainability and energy.
There are a lot of greenhouse builders that don’t yet provide greenhouses to cannabis that have really sophisticated systems to optimize diffusion, so they’ll paint the floors flat white and they’ll have diffused glass, so they pretty much create a fog of light around the plant. So this appreciation for having light everywhere has been in production for decades. It’s nothing new, and I knew by capturing more light, we’d see more yield.
MV: Do you feel this opens up avenues that haven’t been explored in commercial cannabis yet? Do you feel like this is something that can actually be utilized?
Higginbotham: At the end of the day, it’s going to come down to an efficient form factor that doesn’t impede on laborious tasks within cultivation.
There’s also research out now that supports that spectrum is not a key driver of the results, meaning that you could apply even more efficient fixtures beneath the canopy, thereby applying the same amount of light but now with even less energy use, so that’s another upside.
I think it really needs to cause cultivators to change their thoughts around expanding or further optimizing. There are many operators who have systems that have fixed direct costs. I don’t care how good they are at turning their square footage on a perpetual schedule, they’re going to have fixed direct costs unless they can push higher yields. So their only option right now is to expand, take up more area, use more resources, hire more headcount.
Or, by optimizing, they could use the same amount of energy, increase yield by 20% to 30% and reduce their cost per pound, skyrocketing yields without hindering quality. I think it’s a huge shift in how we should think about optimizing, especially from a cost perspective.
I now have almost 30% higher yields. My cost per pound dropped no less than 20%. We’re trialing five different fixture types right now. I have over an acre and a half, and we’re trialing with hanging lights beneath the canopy, hanging them side by side, you name it. And then I’m working with some other indoor growers that have deployed both top lighting and fixtures beneath the canopy, and we’re seeing yields that I’ve never seen before on a square foot basis.
MV: It also seems like an easy way of reducing the disparity between your top buds and the rest of the buds that often get blocked by leaves and don’t end up developing as well as the top-tier buds do. Do you think that’s accurate?
Higginbotham: I couldn’t agree more. This directly impacts value per square foot. The reason those flowers are now larger is because we’re getting light directly to them. In California, right now, the wholesale bulk price per pound on premiums (A&Bs) for greenhouse product is $550 to $710 per pound. On smalls (Cs+), it’s $250 – 300. If I can increase premiums in a single square foot by 27%, that alone changes the game, separate from an increase in total yield of 20% in general. If I were just able to get the increase in premiums, that would still pay for the ROI of the fixtures, but not only do we get that, we get an increase in total yield by 20%.
There’s a lot of other things that this starts to offer — one of those being in many cannabis systems, you have labor costs tied to plant count. And a lot of growers like to plant one plant per square foot, but we’re seeing those that use intercanopy lighting, can reduce their plant count by 30% and still have higher yields, plummeting their cost per pound.
MV: Cannabis is still an energy intensive industry, event with the advent of better LEDs and other technologies. What do you see in terms of intercanopy lighting improving the energy efficiency/sustainability component for cannabis businesses?
Higginbotham: Energy companies should judge performance of a plant-growing business based on energy use efficiency. I should be judged in grams per kilowatt hour per cycle or per year.
We have to look at the total units of electricity used in relation to the units produced in biomass. That should give us an efficiency metric, and therefore a metric used to determine performance. And that’s not at all how cannabis is judged.
This could open the door to saying, “Yes, this grower uses 10% more energy, but it’s producing 40% more product.” Change the conversation to efficiency of utilization, and wrap incentives around that, which would also prevent growers from being so at-scale, when they could produce so much more in a smaller footprint. This is really opening the door. There’s no other plant that can tolerate 60 DLI, let alone 80. And cannabis is showing to do that. So it’s quite fascinating what this could turn into.
This interview has been edited for length and clarity.