Considerations for layouts, irrigation systems, and more when growing in tiers
James Cunningham started growing cannabis indoors, on a single tiered surface under high pressure sodium (HPS) lights. The setup worked for more than a decade, but the advent of more efficient light-emitting diode (LED) lighting inspired him to rethink the setup at Fog City Farms.
“For a long time, LED had a bad reputation for underdeveloped flower growth,” recalls Cunningham, CEO of Fog City Farms, based in Santa Cruz, Calif. But then things changed. “We started to hear from a few different LED growers [who] were producing comparable yields and comparable quality flower to HPS.”
In 2017, citing the high cost of square footage for indoor space in Santa Cruz and advances in lighting technology, Cunningham transitioned to a two-tiered vertical system with LED lights for cannabis plants in the flower stage. In the vegetative growth stage, plants remain in a greenhouse where square footage is less expensive and lighting requirements are lower.
Cunningham credits the move with providing the space he needed to develop the Fog City Farms brand and sustain its wholesale operation.
“When you go vertical, you’re producing half the heat with [LED lights] with the same amount of cooling,” he explains. “What we used to have to build a two-story building for, now we can throw up some racks and make use of our cubic footage rather than [our] square footage.” In other words, since Fog City is already cooling the air above the canopy, it leveraged LEDs’ lower heat loads to “grow up.”
Matt LaBrier also adopted a vertical strategy to maximize the cubic footage when designing the Proper Cannabis facility in St. Louis, implementing double- and triple-stacked systems utilizing LEDs.
“[Under LEDs] we were seeing buds that were tighter and terpene tests that were higher than what we’d see with traditional HPS lights,” says LaBrier, chief operations officer at Proper Cannabis. “We knew that if we were going to build a facility and consider it state-of-the-art, HPS and a single-tiered system was out of the question.”
Adopting a multi-tiered operation is not without its challenges, however. These best practices can help growers transition to LED lighting in vertical systems.
When planning Proper Cannabis’ 90,000-square-foot cultivation and manufacturing facility, LaBrier knew that a vertical system would require workers to move scaffolding in and out of the flower room and climb ladders to access plants on the top racks. The layout had to include wider aisles to accommodate the additional infrastructure.
“One challenge to vertical farming is efficiently working on the upper tiers,” says Jeff Gumaer, Proper’s cultivation director. “The primary reason for a wider aisle would be to access these spaces with your equipment. The rows don’t need to be wider than 4 feet to execute this, but you have to have the right tools.”
Proper Cannabis uses a specially designed platform system that can fit within that space and expands to 7 feet lengthwise, allowing two team members to work on the equipment at one time.
“It also folds up so that it easily rolls in and out of our aisles when we need to move the workstation,” Gumaer says.
Growers must use different strategies for plant spacing in a multi-level LED system than a conventional single-tier operation using HPS lights. The reason? Depending on the fixture, light intensity drops dramatically the farther plants get from the LED lights. However, because LEDs produce far less by-product heat, plants can be placed closer to the fixtures to create an equivalent relative light intensity at canopy. The correct spacing between the light source and the plant can create dramatically different results for cannabis plants in flower.
“Under LED lights, cannabis plants growing 6 inches from the lights can thrive, showing no signs of light or heat stress,” LaBrier says. “Plants growing too close to HPS lights would be hating life.”
Proper uses a PAR meter to measure light intensity at the top of the canopy and adjusts the lighting accordingly to target a 700 to 900 photosynthetic photon flux density (PPFD) range, Gumaer says.
“The distance between your plants and lighting in any stage of growth has to do with what percentage you are running your lights on. A general answer would be 12 inches to 18 inches from the lights at 100% output,” he says.
In a vertical system, Cunningham suggests shrinking the space between the light and canopy and controlling the environment so your genetics can produce to their full potential.
Managing environmental factors like airflow, humidity, light intensity, and vapor pressure deficit is essential in all indoor farms, especially in vertical grows.
“The more plants there are in a room, the more chances there are for microenvironments to develop throughout the space,” LaBrier explains.
In fact, LaBrier says that there can be hundreds of microclimates within a 10,000-square-foot room. To maintain the right environment, he suggests growers install additional sensors to track data at various ceiling heights, different plant heights and even within trays.
“There is less air movement, and it’s a few degrees warmer on the top rack,” he explains. “When you think about a production plan … you have to be really cognizant of where we’re putting certain strains because there are small microclimates throughout the room. It’s true of traditional growing, but it’s exacerbated by vertical growing.”
Irrigating multiple levels of cannabis plants in a vertical system can lead to disproportionate runoff to lower tiers. To avoid overwatering, Cunningham suggests choosing the correctly sized pipe diameter for each tier to balance the irrigation supply and properly sized pressure regulation emitters to ensure an even distribution of water, isolating supply channels to service different levels.
The irrigation piping also determines the height of the bottom tier, as gravity requires a certain amount of fall per foot for the water to drain. To maximize the number of levels and start the bottom tier as low as possible, it’s best to place the drain in the middle—or install multiple drains—to minimize the drop needed to drain the water, Cunningham adds.
The intensity of LED lights combined with growing environment modifications can lead to faster plant growth. One study published in Agronomy Journal found that plants grown under LED lights produced up to 800 grams of cannabis compared to 300 grams for HPS-grown plants.
Faster growth might seem good for growers transitioning to LED lights in a vertical system, but it requires managing to ensure plants don’t get too close to the light in the flower stage. Growers also have to consider how it will affect their workflow, LaBrier adds.
“LEDs help push plants along a little quicker in a positive way, and things that used to take nine weeks were finished in eight or eight-and-a-half-weeks,” he explains. “You have to think logistically about how that will work in a commercial operation where you harvest every week and how it interacts with hang times and cure times.”
While the approach to vertical farming in flowering is different than a traditional single-level, transitioning to a multi-level farm is worth the effort and investment, Cunningham says. He believes it’s the future of cannabis.
“There are huge advances being made with LEDs,” he says. “As power becomes more of a regulator in the indoor farming space and farmers educate themselves, everyone is going to go to LED in vertical farming.”
Jodi Helmer is a North Carolina-based freelancer who covers the intersection between agriculture and business.
Note from Fluence CEO David Cohen
Growing Under High Light Intensities
5 Best Practices for Vertical Farms
Successfully rooting and transplanting your clones will save time and protect your profits.
Cannabis clones consist of a small cutting taken from a plant typically in its vegetative stage. This cutting is stuck into a rooting media where it sits for a few weeks until rooted well enough for transplant. When done correctly and transplanted appropriately, clones can be cannabis’s little miracles, saving you thousands on seed money each time you plant a crop.
While techniques and equipment may vary, there are two main approaches to cloning: automated, or by hand.
Here, we explore each process and offer tips and solutions to common rooting and transplanting problems.
Hand-cloning takes more time than using an automated propagation system, but it is a route worth exploring if you want to execute a craft-cannabis approach or cannot afford the upfront automation investment.
The manual cloning process is very simple: Start by identifying the strain you would like to clone, then take “cuts” from the chosen plant or plants. Each cut should be 6 to 8 inches in length. Try to cut the clone as close to the node of the stem (where the targeted cut meets the branch it’s connected to) as possible—this will help the plant heal more quickly and be less susceptible to disease in the future.
Take all the cuts you need to fill your tray and stick them in cups of water so they do not wilt. It is important to minimize the amount of time the cuttings are exposed to air. The quicker you are able to stop the stem from absorbing air, then the better your clones will fare. In addition to having a pH level of around 5.5, the water you put them in can also include some sort of nutrient or cloning solution to help aid in the cloning process. Having the nutrients available from the second the clones are cut helps improves survival rate as the clone can uptake nutrients despite the absence of the mother’s root system. Once you have collected all your clones, you can store them in a fridge while you prep your tray.
Most rooting media trays have what are called dibble holes, which are predrilled holes for you to stick the cuttings in. If the trays do not come with dibbles, you may want to make a small hole beforehand so you do not bend the cuttings.
Prior to sticking your clones in your rooting tray, the tray should be very moist but not soaking wet. If it is dry, the media may draw moisture from your cutting, reducing your rooting success odds. The tray can be saturated with a nutrient or cloning solution in addition to water to aid in the rooting process. The cutting will have some nutrients stored in its leaves, so very little additional nutrition will be needed. That said, mycorrhizae or beneficial bacteria can be used to boost the odds of successful rooting.
Once your tray is wet, grab your clones and, one by one, begin to cut the fan leaves off the cutting. Keep the top leaves along with the next two nodes below it (minus the fan leaves). Then, cut a 45-degree angle into the bottom of the cutting, leaving it between 3 to 6 inches tall, and stick the clone in the rooting media.
While you are sticking your clones, it is best to try to leave them soaking in the cup as long as possible. You may also want to use a spray bottle with your cloning solution to treat the cuttings that are in the tray to prevent wilting.
Finally, after the clones are in the tray and are moist, you can put a dome on top of the tray and begin the rooting process. With the domes on, keep the humidity high for the first few days and then dial it down after the first week. Keep the rooting media moist and add nutrients for the developing roots to start absorbing after the first week. Minimize the lighting intensity above the clones.
After 14 to 21 days, white roots should begin to form as long as the clones become small plants. Once roots are nice and pronounced and clones begin to grow again, then you can transplant the new plant (more on that later).
The manual transplanting process begins with selecting your tray of clones. Make sure they have healthy roots by tugging on a few of them and checking the roots underneath the growing medium. If roots are just poking out from the bottom, the tray is not ready. If roots are prevalent, plant as soon as possible. The goal is to avoid roots circling around the bottom of the tray and becoming rootbound, as this will stress the new plants out.
Be sure that each clone’s rooting media is wet before transplanting into another pot. The plant will draw all the water from that cube before drawing water from the new soil around it for the first couple of days, so be sure to keep it wet.
After checking for healthy roots, plant each clone in a pot that is 2 gallons or less in volume. While this is a good size for initial transplant, a larger pot can be used. While transplanting into a larger pot will increase rooting times, it also means you will have a longer period of time before the plant needs to be transplanted into a larger pot (if at all).
Place each clone into the pot with about an inch of soil covering the clone base. If they are abnormally large, they can go a little deeper into the soil, but never against the bottom of the pot. Roots tend to grow downward, so placing them on the bottom makes it difficult for them to establish a great root base. Once you have placed your tray in the pots or before the end of the day, water the new transplants well so that the soil is wet throughout the pot. They should establish roots within a few days as long as they are not over- or under-watered. Depending on if your soil has nutrients in it already or not, make sure they are being fed immediately to avoid deficient growth.
A very good crop can be produced using automation, and propagation is often one of the first places cultivation companies start automating because of the proven success and labor hours a company can save in one cycle alone.
First, begin by taking cuttings of the selected cultivar. Clean them for the automated clone planter by taking off the lower fan leaves and cutting the bottom at a 45-degree angle to make the clone reach 3 to 6 inches in length. Then, load your cuttings in the machine or place them in cups with water for short-term storage. (Adding a cloning solution to the storage cup is still recommended.)
Make sure the clone trays are loaded in the autoplanter and turn the machine on. The machine will fill and moisten the tray. Then, take the loaded tray and place the clones under your automated propagation area.
Some automated propagation systems are set up with misters to add humidity; others have a boom with which you can spray water or nutrients from above. Make sure the misters or boom are set up for the new crop and place the tray in the appropriate area. Your automated misting schedule may need to be adjusted after a few days to start to harden off the clones, which will begin the rooting process. Typically after the first week, nutrients are introduced and light intensity can increase. After 14 to 21 days, strong roots will appear, and you can begin to transplant the new plants.
As with cloning, transplanting clones can be a totally automated process.
Automated clone transplanting requires much less human labor at many times the speed, but typically costs much more upfront.
Select your tray just as you would for the manual process, and once trays are healthy, load them in the transplanter, along with pots and soil. The transplanter will move the transplants onto a conveyor that could be fed to your tables or vegetative area. Water and nutrients can be introduced by the transplanter, as well. After a few days, roots will establish, and the vegetative process will begin.
With financing becoming more available for cannabis growers in the coming years, automation likely will be the way most cannabis is produced in the future (with the exception of craft farms who will hold a share of the marketplace). That said, machines break every day, so having protocols in place to hand-clone can save days, if not weeks, of delays.
Gevin Gros is a cultivation consultant in the cannabis industry.
Marina Hahn, a SVEDKA Vodka founder, explains what companies need to do to elevate cannabis-infused beverage brands.
In May, vertically integrated multistate operator Jushi Holdings Inc. announced it had appointed SVEDKA Vodka founder Marina Hahn to its board of directors. With decades of experience at beverage behemoths such as Pepsi and Anheuser-Busch, Hahn’s expertise is in creating and identifying strong, fast-growing brands that resonate with consumers. Four years after founding SVEDKA Vodka, the startup became one of the top-selling vodkas in the U.S., and Constellation Brands picked it up for $384 million in 2007.
“I’ve wanted to get involved because I love emerging businesses, and I’ve tried to be a part of emerging businesses my whole career,” Hahn says. “The other reason why I joined cannabis is that I predict the cannabis beverage segment could be a huge movement in the world of beverage.”
Marina Hahn: My advice would be get in early to compete in emerging beverage segments and try to be a first mover in beverage innovation. I have learned many lessons working at Pepsi and ultimately at Anheuser-Busch and starting my own business, SVEDKA Vodka, they know their audiences really well, and that's critical. We also take packaging very seriously, that’s critical. In the world of cannabis, there are going to be many cannabis beverages, but the key is how you differentiate a beverage so that it is truly unique and is something that the consumer didn't know they needed but, after consuming, really desire it.
Cutwater [Spirits] canned cocktails is now a no-brainer, as canned cocktails are everywhere, but when Cutwater was an emerging business, Anheuser-Busch was smart to buy them. So that's an example again of us getting in early to emerging segments and trying to be a first mover in innovation. I think that's important for cannabis.
MH: [For] people [who] don't want to smoke, there [will be] plenty of other options to get that enhanced value, whether it's medicinal or whether it's just for pleasure. The consumer usually gravitates to brands that are meaningful to them and that they can emotionally connect to. So how do you do that through packaging, product, and messaging? There are so many elements from the world of spirits that will probably migrate over to cannabis; it's not an if, it's a when. Why it hasn't happened is probably because it's an emerging space and the kind of people who understand that business are just not in cannabis yet. I think there needs to be a more sophisticated approach to strategy and creative in the world of cannabis to create the growth in beverages.
MH: [You] can't assume you're going to be able to do it all with a) small budgets and b) without the right team and c) without a really sound strategy. My advice is always, don't try to do too much and build it slowly, and build it against a very finite target audience initially. Make sure you've got the right people who have done this before so you're not just blindly creating brands that won't have stickiness down the road.
MH: I envisioned an outrageous fem bot spokesperson, who we called SVEDKA_Grl, who became this pop culture icon. Talk about small but efficient budgets – everything was geared towards her, and she became emblematic of the brand. And then ultimately we became national with our marketing spend, but she was just visually arresting, and she broke through all the competitive clutter. Once I launched her, SVEDKA sold like crazy, and we sold to Constellation [Brands] four years later.
MH: Look at really smart brands that are suddenly household names and how they started, and try to take lessons from them versus using the conservative consumer goods company approach to building businesses. It doesn't work that way anymore. It's important to carefully target and develop great creative, but it's also about using data strategically to deeply understand your customer.
This interview has been edited for length and clarity. Read the full conversation here.
Six years of research on the cannabis cultivation lighting market, including what's changed and where the industry might be headed
Click on image below for PDF of the full report.
Click on image above for PDF of the full report.
Note from Fluence CEO David Cohen
Growing Under High Light Intensities
5 Best Practices for Vertical Farms
Researchers and growers continue to explore how high light intensities can optimize cannabis operations.
For cannabis growers operating in greenhouse or indoor cultivation facilities, finding the perfect lighting strategy is an ongoing quest. Advances in lighting technology continue to illuminate the complex relationship between cannabis and light. For many growers and researchers, the emphasis has shifted from light color or spectral quality to light intensity—specifically, high light intensities that go beyond sunlight intensity.
To understand what constitutes high light intensity, Mitch Westmoreland, Ph.D. candidate and Research Associate at Utah State University’s Crop Physiology Lab, starts with simple reference points—like the sun.
Photosynthetic photon flux density (PPFD), measured in micromoles of photons per square meter per second, remains the standard of measurement for light intensity in growing environments. Westmoreland describes PPFD as an instantaneous value reflecting how much photosynthetically active radiation (PAR) hits the leaf each second.
In Westmoreland’s experience, he’s found many cannabis growers happy to hit 700 to 1,000 PPFD. For perspective, he puts peak outdoor light intensity on a midsummer day at 2,000 PPFD.
Jason Sanders, head of cultivation at Texas Original Compassionate Cultivation (TOCC), estimates the average cannabis facility grows at 900 to 1,000 PPFD during flower. TOCC grew in that range before beginning research on spectral quality and light intensity in early 2020 in partnership with Fluence by OSRAM.
“If you can get above 2,000, you’re really pushing it,” Westmoreland says. “That’s a very high light intensity.” But he cautions that photosynthetic rates level off dramatically when PPFD exceeds 2,000 micromoles.
TOCC’s light intensity trials with sole source lighting have involved PPFDs from 1,000 up to 2,500—an upper limit determined mainly by the facility’s power capabilities.
“We maxed out our load,” Sanders says. “We learned that the best value was around that 1,800 micromole level for cannabis. As we start increasing from 1,000 micromoles up to 1,800, we saw about a 1% increase in yield for every 1% increase in light intensity. That started to diminish from 1,800 to 2,500.” While yield increased up to 2,500 PPFD, it was more bell curve than linear beyond 1,800 PPFD.
The biggest surprise? “It was amazing to see the plants take the light,” Sanders says. “I would have thought that we would have seen some type of phototoxicity—some kind of leaf curl, burning, something—but the plants were able to handle it.”
Although cannabis is a high-light crop capable of achieving high photosynthetic rates at high light intensities, Westmoreland says there’s a ceiling to how much light any plant can take.
“Physiologically, plants can only handle so much in terms of using that energy for photosynthesis, and so they have to come up with ways to dissipate that energy,” Westmoreland says.
When light overwhelms a plant’s photosynthetic machinery, damage can result. Researchers are still discovering how cannabis handles stressors that come with high light.
TOCC’s next study is focused on effects of different light spectra at various PPFDs. The best yields to date have been with Fluence’s broad-spectrum R4 lighting. Type 1 (high-THC, low-CBD) cannabis grown at 1,500 PPFD under R4 showed 17% higher yields in dry bud weight as compared to R6. Higher fractions of red light (corresponding with higher R numbers) tracked lower yields for the company.
Westmoreland and Sanders report photobleaching—bleached, white flower tips—at higher light intensities with test treatments where more red is added to the spectra. For TOCC, no photobleaching was observed under R4 spectrum at PPFDs of up to 2,500 micromoles/m2/s.
“Photobleaching seems to be an interaction between light intensity and light quality,” Westmoreland says. “It seems that a higher fraction of red makes plants more prone to photobleaching. It also tends to happen just at the high light intensity, regardless of the fraction of red.” He suggests photobleached tips are most likely above 60% to 70% red.
But Westmoreland also notes USU testing shows photobleaching does not lower cannabinoid concentration or affect yield. “It’s just a cosmetic thing,” he says.
Westmoreland says USU hasn’t yet seen good evidence that cannabinoid concentration increases in proportion to yields under high light intensities. “But it does take energy to make cannabinoids. It takes energy to make terpenes. The source of that energy is light. So, it’s not completely ridiculous to think that more light also means more cannabinoids,” he says. “The gray area there is we don’t necessarily know what the ceiling is yet.”
Exploring that relationship is now a focus for USU researchers. “We have sufficient evidence that spectral quality might have a small impact on cannabinoid concentration and morphology, but the bigger question is what does light intensity do?” Westmoreland says.
A new state-of-the-art, 10-chamber, canopy gas exchange system may help with answers. “We can look at photosynthetic responses in real time to the different light intensities, and we can also relate that to yield and cannabinoid concentration at the end of the life cycle,” Westmoreland says. “We’re also looking at the interactions with high light and nutrition and high light and temperature, because all of these things interact and affect yield.”
When TOCC first began lighting studies, the 2,000-square-foot facility grew under high pressure sodium (HPS) bulbs. An interest in LEDs and the opportunity to conduct lighting trials and see LED benefits led to change, and TOCC now runs all LEDs with dimmable switches.
“I think the greatest challenge for growers now is being able to hit those high PPFD numbers and still have the environmental parameters still dialed into the grower’s setpoints,” Sanders says.
In HPS grow setups, growers will need to increase their number of lights and ramp up HVAC systems to handle the added heat load. “With the new technology of LED, then you can get to those light levels without having the heat problems,” Sanders adds.
Westmoreland agrees that extra thermal load is an obstacle for HPS growers at high light intensities: “That’s where LEDs become really nice. They don’t have quite as much thermal radiation, and the thermal radiation they do produce goes up, away from the plants. So, you can run these lights much closer to the canopy and potentially get a higher light intensity.”
When TOCC started growing under high light, plants grew in peat-based media in No. 5 pots. It is now trialing 6x6 rockwool cubes. Sanders feels the larger root zone offered a buffering effect at high light intensities; smaller root zones are much less forgiving. “You’ve got to really be on your A-game,” he says.
By growing under higher light intensities, the plant responds differently to its surrounding environment. With peat, TOCC increased the EC in its normal feed program to accommodate high light in flower. With rockwool, the team runs increased phosphorus at the beginning of flower, then drops back to normal for the rest of the flower cycle.
Sanders also increased TOCC’s veg cycle from two weeks to three, to allow more maturation before rockwool-grown plants hit high light. Propagation runs at 150 to 200 PPFD. In veg, that jumps to 350 to 550. From veg to flower, Sanders slowly increases intensity from 550 to 1,800 PPFD during a week-long photoacclimation that kicks off eight weeks of flower. He’s also increased CO2 enrichment levels to between 1,000 and 1,200 ppm.
Westmoreland reminds growers to have a light meter and use it. “The human eye is a terrible light meter, especially at high light intensity,” he says. He suggests monitoring throughout the day over the course of a few weeks, especially if you grow in greenhouses that experience light fluctuations. From there, expect water demand to increase under high intensity, and adjust nutrient solutions to accommodate the change.
Westmoreland encourages growers to look at daily light integral (DLI, the amount of PAR light hitting a designated area over 24 hours), not just instantaneous PPFD.
“If it’s raining outside, you’re not really interested in how many raindrops are falling at any given moment. What we’re interested in would be accumulated total. That’s the exact same thing for plants,” he says. “We can think of photons as raindrops. We’re not necessarily interested in the instantaneous number of photons hitting a crop or a leaf at a given time, but we’re interested in the long-term accumulation of those photons. That’s ultimately what’s contributing to the yield.”
Westmoreland explains that outdoors in Logan, Utah, where he’s located, the maximum DLI in midsummer is about 60 moles per meter squared per day. (For context, 1 mole equals 1 million micromoles.)
While outdoor light intensity varies throughout the day, controlled environments can run constant light intensity all day long. “You can get daily light integrals that are approaching 100, depending on how hard you push your plants. That’s what I would consider to be high light intensity in terms of integrated over the whole day,” he explains.
As growers advance in understanding optimal light intensities for cannabis, Westmoreland says the total amount of light accumulated over the entire crop is key.
For Sanders, it’s an exciting time. “I think that it is really awesome that we’re in a time period now where we can look at kind of a light recipe here. We can dial in intensity, so we can start at low PPFDs and then ramp them up as these plants get into flower and really optimize it,” he says. “As a grower, it’s awesome to have this extra tool in the toolbox now.”
Jolene Hansen is a freelance writer specializing in the cannabis, horticulture and CEA industries. Reach her at jolene@jolenehansen.com.
Note from Fluence CEO David Cohen
Growing Under High Light Intensities
5 Best Practices for Vertical Farms
Cannabis Business Times’ interactive legislative map is another tool to help cultivators quickly navigate state cannabis laws and find news relevant to their markets. View More