When Denver-based Lightshade and multi-state operator Holistic Industries made the switch from high pressure sodium (HPS) lighting to light-emitting diode (LED) technology in their cannabis cultivation facilities, each operation’s retrofit presented its own set of challenges and lessons learned, but both journeys started with similar reasons for the switch.
Dan Banks, the vice president of cultivation for Lightshade, says he analyzed the total amount of illumination needed at the company’s 20,000-square-foot greenhouse facility and determined that the 336 supplemental HPS lights in the space did not provide enough luminosity.
“You can get more illumination per watt of power used by the LEDs versus traditional HID/HPS lighting,” Banks says. “It’s more bang for your energy buck. For us, it was less about using less energy and more about using the energy more efficiently.”
In the spring of 2020, Lightshade installed roughly 200 of Fluence by OSRAM’s VYPR LED fixtures to complement its HPS lighting, and this past spring, the company commenced replacing all of its HPS lights with 440 additional LED fixtures.
“In terms of selecting the Fluence VYPR, my colleague, Nick [Drury], in his capacity working for MJardin in the past, had done a lot of different trials with LED lights, and he had liked what he had seen with Fluence,” Banks says. “… You know that they’re investing in the further development and R&D of their fixtures, and you know they’re going to support the lighting technology. That was big for us.”
Banks and his team were also impressed by the VYPR’s full spectrum white light, which allows them to increase the light intensity without photo bleaching. In addition, the low-profile VYPR fixture does not block the natural sunlight in Lightshade’s greenhouse.
Nick Denney, cultivation director for Holistic Industries, says energy efficiency also drove his company to make the switch from HPS to LED lighting, as did yield potential.
“The single biggest driver for yield in crops—not just cannabis, but any crop—would be light intensity, or the accumulation of light intensity over a single day,” Denney says. “With HPS bulbs, you can only get so much before you start having some pretty big issues inside your rooms, mainly with heat removal. With LEDs, you can stack them in closer together, you can get them closer to the canopy, and you have … a higher ceiling for light intensity, if that’s your only source of light.”
Safety also played a role in Holistic Industries’ decision to convert its indoor facilities to LEDs.
“HPS [lights] have gas inside of the lamps, so if one of those falls out of the fixture, we could have huge issues, not just for human health for the people inside of the rooms, but the flower that could be contaminated because of it,” Denney says.
In early 2020, Holistic Industries launched R&D on LED lighting in a few rooms of its Washington, D.C., facility, and later that year, the company began installing Fluence’s VYPR LED fixtures in its Pennsylvania and Massachusetts facilities. The company’s Maryland facilities are currently undergoing expansion, and all the new rooms—as well as the old cultivation spaces—will ultimately use the VYPR fixtures. In addition, Holistic Industries is currently building out new facilities in Michigan, Missouri and West Virginia, all of which will have LED lighting.
“Really what it came down to for us was the technical support and science … that [Fluence is] putting into the industry as a whole,” Denney says. “I’ve felt like that was really what set them apart from other lighting vendors. There are other great LEDs out there, but we were looking for a good partner to work with that would scale with us because we’ve been growing extremely fast.”
The Greenhouse Retrofit
Since Lightshade originally supplemented its HPS lights with LED fixtures before converting all of its lighting to LEDs, the company was able to conduct R&D with light intensity to first test the fixtures’ specifications on a smaller scale.
“We saw a pretty immediate jump in yield correlated with the higher lighting intensity,” Banks says. “That did well for us for that year, and so that’s what led to doing the larger project, getting rid of the HPS and expanding that footprint. Since we did that in the spring of this year, we’ve also seen another jump in yield, so it’s been really good for us in the greenhouse.”
Lightshade took advantage of utility rebates to help finance the retrofit, and once the process is complete, Banks says the company will see a rebate of between $250 and $280 per fixture.
Lightshade mapped out the project with its utility company, Xcel Energy, before purchasing the LEDs and continued to work with Xcel through the installation process to monitor the electrical load.
“The big takeaway is you definitely want to engage with the utility, let them know what the project is and get approval for the project before you pull the trigger on buying anything,” Banks says.
Lightshade uses a palletized moving bench system in its greenhouse. So, as the cultivation staff harvested each section, the LED fixtures were installed as quickly as possible before the area was replanted.
“If you’re [retrofitting] a working facility, you’re not taking the facility offline, but you’re leveraging your harvest schedule to install those lights,” Banks says. “You may invariably end up with a few days of missed flowering time and some complications. … There were some logistical hurdles, but we were able to use our harvest cycle as the guiding light for how to plan that install and reduce downtime as much as possible.”
Lightshade operates a padwall-cooled greenhouse, and Banks says the LED fixtures produce less heat than the HPS lights, which equates to fewer hot spots and reduced plant stress.
However, Banks says humidity levels tend to creep up more with LEDs than with HPS fixtures, due in part to denser plants putting more water into the environment.
“The other difference is that we had less heat being generated by the lights because they’re more efficient,” he adds. “What that means is that our HVAC, in some cases, is actually running a little bit less because there’s less heat in the room. When that happens, you don’t have the byproduct of cooling, which is dehumidification. That can lead to a situation where you have a little bit more humidity in the room.”
In addition to adjusting equipment settings to decrease the humidity, Lightshade has also changed its watering practices due to the plants growing larger and requiring more water, especially in late flower, Banks says.
The Indoor Retrofit
Denney says “it was very difficult” to continue Holistic Industries’ indoor cultivation operations while accommodating the contractors installing the LED fixtures.
“We actually had to take a little bit of a hit on some batches because when you’re switching these lights out, they hang lower than the HPS, and they were blocking light over the canopy,” he says. “In some cases, we’re turning HPS lamps off so we can get the electrical switched over. … A lot of credit [goes] to our growers who guided the process and made it happen. And now, you can see there was a slight dip in yields in those batches when we were dancing with the contractors, but then as soon as the LEDs came online, there’s this uptick in growth.”
Just as with Banks and the Lightshade team, Denney and his staff have also noticed less heat coming off the LED fixtures and have tweaked the temperature in the grow rooms, leading to other environmental changes.
“When you increase temperature, it’s all a chain reaction of events,” Denney says. “You change temperature to keep vapor pressure deficit the same, and you’re changing humidity, as well. When you increase light and temperature and humidity, you’re also going to look at increasing your CO2 concentrations, and that’s all part of keeping the plant in balance.”
Environmental controls are also tied to irrigation practices, he adds, and some of Holistic Industries’ cultivars require higher inputs of fertilizer when grown under LEDs.
The Results and Lessons Learned
The biggest limiting factor in cannabis production is often light intensity, Banks says, and by increasing light intensity with the switch to LEDs, Lightshade has seen a corresponding increase in not only yield, but also the overall quality of product.
“The higher lighting intensity has caused things to be a little bit less stretchy—more dense,” he says. “And the floral structure looks really good. We’re also just getting some data right now—so I can’t say anything conclusive—but based off of some of the research we’ve done on all of this, we’re hoping that we’ll see a change in the potency of the product, as well, but it’s too early to tell.”
Denney says Holistic Industries’ plants received 600 to 900 micromoles of light with HPS, but with LEDs, the canopy receives 1500 micromoles of light, which equates to more dry weight of flower at harvest. On average, the company’s yield has doubled since it made the switch to LEDs, Denney says, adding that product quality and overall bag appeal has also improved.
“I’ve noticed different smells coming off of the same plants,” he adds. “I don’t know if it’s just me and my nose, but there are certain plants that I go in and I smell and I think, ‘This smells fruitier than I’m used to. I’ve never had it smell like that.’ Or there was one variety at harvest that just smelled like skunk, and I never had smelled that before from that same plant, and we’ve grown it countless times under HPS. I definitely think there’s something to that.”
The white light of the LEDs also helps Holistic Industries’ cultivation staff get a better view of the plants, which helps them more quickly identify nutrient deficiencies, pests and diseases.
“They’re able to identify and scout in the rooms better, which leads to a more consistent crop,” Denney says.
The LED fixtures also give Holistic Industries more precise control over light intensity, which helps its crop steering efforts.
“With LEDs and the increased light intensity, we’ve gained a lot more control over the plant and pushing it one way or the other, either toward vegetative growth or generative growth, and that’s really important for us because we’re trying to grow a lot of variety,” Denney says. He added that the LED fixtures give the company the needed control to grow craft cannabis at scale.
Banks urges other cultivators looking to convert their facilities to LEDs to think through the timeline of the project and the steps needed to complete the installation.
“That requires bringing together contractors to do the installation and the infrastructure,” he says. “That also means engaging with an electrician … and really laying out a good team and a good plan so you can minimize any downtime at your facility.”
Cultivators should also understand what they want to accomplish through the retrofit, Banks adds. “If you want to save energy, then doing a fixture-for-fixture replacement is really the way to go. If you want to maximize your output, then you look at your current lighting map and then you can ask your LED company you’re working with … to do all that light mapping for you and give you some options.”
