Photo courtesy of bridget behe

Greenhouse Management: Now that we are at last somewhat past the pandemic’s peak, how is green retail doing and what has changed?

Bridget Behe: I think a big uptick in interest and in purchases, particularly for 2020, remains true. I think we saw things being sustained into 2021 too. Most folks that I’ve interacted with have had another good year. I think we’ve got an opportunity to keep the train moving down the track and I think we can capitalize on that. But I also know that folks are stretched thin, especially with the lack of available labor [in some places]. I think it’s going to be, as it always is, a challenge.

GM: Where do you think growers’ heads are at currently?

BB: I interact more with retailers, but I think growers are more concerned about what they are going to grow and how it’s growing more so than the quantities for next year. Though I do not think that anyone is going to go up dramatically in scale again. I think, conservatively, there might be a plateau. But optimistically, I think we can still affect some kind of increase. I think some of that revenue increase is going to have to come from raising prices that are not easily compared. For example, four-inch geraniums or six-inch poinsettias or a flat of impatiens — those are what we call sign-post items. People can, and do, price shop on some of those items. Particularly the mixed containers and some of the hanging baskets, I think that’s the space where most retailers are going to have a chance to recoup the cost increases that they are facing right now. But I think there is great reason for optimism, but I don’t think anyone is expecting another 30% increase for 2022.

GM: How are retailers when you interact with them?

BB: They are stretched thin, too. The labor issue is affecting them just as it is affecting not just horticulture, but all other industries. So having to do more with fewer people has really stretched them a bit further because some of them are still trying to do online orders and curbside delivery. And those were options that, before 2020, really didn’t exist for most retailers. Those who had already gone down that path were in a better position to respond to those needs. But a lot of retailers jumped into those either in a limited or extended capacity. That certainly stretches your business model if you don’t have good labor ready to work. And it might not be something that they feel they can walk back now even as more customers come back to the store.

Photos by Steve Galicza

In the cannabis industry, where margins are tight and legal and logistical challenges are the norm, cultivators are constantly looking to improve efficiency and productivity. GreenSeal Cannabis Co. looked to new heights for a solution to expanding its business: by growing cannabis vertically.

Based in Stratford, Ontario, Canada, GreenSeal Cannabis operates a bold six-level vertical grow as part of its 28,000-square-foot operation — half of which is used for cultivation, the other half for supporting infrastructure, according to Phil Niles, executive vice president.

“Our first room was two levels, our second room was five levels, and our latest room is six levels … under a 20-foot ceiling,” Niles says. “It just shows that evolution [as we’ve grown up] and figured things out.”

Maximizing Square Footage

Founded in 2014, GreenSeal Cannabis broke ground on its new facility in 2015. The indoor operation was completed and licensed in 2017, and the company began growing and selling cannabis later that year.

“At the time, licensed square footage was so expensive in Canada,” Niles says. “Southwestern Ontario, where we’re based, has some of the most expensive land prices in North America. The cannabis company costs [required] to get licensed and set up were huge. It was so expensive.”

Facing those daunting costs, GreenSeal Cannabis shifted its perspective upward to maximize its capacity with vertical racking systems. According to Cannabis Business Times’ “State of the Lighting Market Report,” the number of cultivators using tiers in both the vegetative and flowering stages has increased during the past three years, with 38% of participants indicating they grow vertically in veg and 20% in flower in 2020. However, only 1% noted they are taking the GreenSeal approach and using more than five tiers in their flower rooms.

“We looked up at this big, cavernous space because our building here has 20-foot ceilings,” Niles says. “We were like, wait a second. We’re paying to buy it, to outfit it, to heat it, to cool it, to clean it, to license it, to secure it—we’re paying for all these different things and it’s sitting there. That was sort of the ‘aha’ moment where we said, ‘We need to stop thinking about square footage; we need to start thinking about cubic footage.’ And that was the turning point.”

GreenSeal started with a two-level vertical grow room before advancing to five and now six levels. An eight-level veg room is in the works, and GreenSeal and has realized improved efficiencies along the way.

“If we take a step back and compare it to our first room, which is a two-level room, that room was kicking off 400 kilos (nearly 900 pounds) per year,” Niles says. “Now [our latest flower room] is kicking off 1,500 or 1,600 kilos per year on six levels. So even though we tripled our number of levels, we quadrupled the harvest size.”

While GreenSeal uses a number of metrics to gauge its business, the company says grams per watt is the most telling.

“Everyone calculates their own metrics within cannabis cultivation,” Niles says. “We love grams per watt because it’s probably the best measure of how much the plant is taking its energy source and converting it into the ultimate biomass that you’re looking for at the end. Why are you powering your plants? You’re powering them to get that yield. So why wouldn’t you do that calculation? It makes perfect sense.”

Innovating With R&D

With six levels of vertical cultivation, GreenSeal Cannabis gets about 90 harvests per year, providing ample opportunity to fine-tune its production processes and efficiencies. Niles credits the company’s “foundational” commitment to research and development as key to GreenSeal’s continuous improvement.

“In one year at GreenSeal, you get 25 years of harvest experience (compared to a typical greenhouse operation), which is partly where a lot of this R&D comes from,” Niles says. “We just have so many opportunities for learning.”

Through all those harvests, GreenSeal’s growers are constantly innovating and exploring ways to improve the company’s mix of cannabis products. However, none of that continuous improvement would be possible without access to testing and lab results, says Chad Morphy, master grower and co-founder at GreenSeal Cannabis.

“The biggest thing that’s given us the ability to push things a little bit further is the fact that we can now [access] cannabinoid and terpene test results,” Morphy says. “The old system was very much based on appeal, flavor or a certain thing we were looking for at the time, but it’s become much more scientific for us now. We can still use our sensory experiences of smell and feel and density, but we can add on these layers of being able to really dive into 150 different terpenes that are there.”

Through its in-house genetic selection program, GreenSeal selectively breeds strains with a focus on strong tetrahydrocannabinol (THC) levels and interesting terpene profiles, including cultivars like Chemdawg Ultra, Mango Kush and Gorilla Berry—the last being a “unicorn” in-house strain unique to GreenSeal.

The decision-making process of what to cultivate, however, involves a number of factors, including selecting plants specifically for their vertical grow system and eliminating those with weaknesses, Morphy says.

“We do a very custom light ramping routine or light schedule we’ll call it. Part of that has to do with height. And even if they don’t quite match our system, we normally are able to manipulate them through topping or through other methods in order to try to keep them a certain size,” Morphy says.

According to Niles and Morphy, GreenSeal Cannabis is best known for its premium flower and pre-rolls and, therefore, has been able to improve its products through the company’s research and development.

“For something that you’re going to put into a pre-roll, you’re going to want something that’s a lot higher in a sesquiterpene profile because it will hold the flavor throughout the entire joint better than something that’s a monoterpene where, when you light it, the first bit of heat that goes through tastes great for two pulls, and then it doesn’t taste great for the rest of the joint,” Morphy says.

Perhaps the biggest advantage of GreenSeal’s in-house breeding and genetic selection programs is the company’s ability to adapt and grow alongside the industry and consumer preferences.

“So far, at least, this industry is not like the beer industry,” Niles says of cannabis consumers. “If you drink Budweiser, that’s what you drink, and people don’t generally stray too much. Cannabis isn’t like that. People want to try different things. They want to explore new terpene combinations and new cannabinoid preferences and things like that, so we’re always looking for what’s next.”

Conquer Vertical Obstacles

While vertical growing can be fruitful, there are dozens of challenges that come with this cultivation approach. Niles says GreenSeal had to tackle numerous obstacles to implement vertical growing.

“One of the first problems that we had to solve with growing vertical was warm air and humidity rising,” Niles says. “How do you make sure that the plants at the top of the room are getting the same temperature and humidity as the plants at the bottom? You really have to keep a very close eye on building infrastructure and automation [issues], because if the power goes out and humidity spikes for an hour, you’ll kill the entire room. There are a lot of risks that come with this [growing method].”

Yet another logistical challenge of a vertical grow is irrigation and nutrient delivery to plants in the top rows.

“You pump water up; well, gravity is going to force that water down,” Niles says. “So how do you make it so the water and nutrient delivery at the top is the same at the bottom? It’s part engineering challenges and part physics and math that you have to work out. Working with trusted, talented third parties can be really helpful on this front.

“We run a hydroponic system, which naturally uses a lot less water,” Niles added. “We see some people in vertical growth have a tendency to overwater, and they’re flushing thousands of dollars down the drain every month from either wasted nutrients or, probably more critically, wasted time, because it takes time to water six levels of product. It’s definitely a facet that people need to be quite mindful of.”

When it comes to lighting, GreenSeal Cannabis opts for LED lights as opposed to high-pressure sodium (HPS) or metal halide (MH) fixtures. In fact, before settling on a lighting solution, the company partnered with a local research university to publish a peer-reviewed study of cannabis lighting intensity.

“It’s nearly impossible to [grow vertically] under HPS or metal halide lights because they simply give off too much heat,” Niles says. “You’ll cook your plants [unless] you use LED lights.”

With these potential equipment challenges in mind, Niles suggests having “redundancy on top of redundancy” to best prepare for unexpected failures.

“With temperature, humidity and lighting, we have four fail-safes in place—backup generators, automated dimming of lights, etc.,” Niles says. “If the power’s reduced for some reason, automated alerts are sent to a few different people who live in the area to come in and [fix] it.”

GreenSeal Cannabis also considered how vertical growing would impact the company’s workforce of 41 employees, all of whom are full-time, with 18 to 20 devoted to cultivation.

“I would say every one of our employees would rather work on levels two through six than level one,” Morphy says. “Because [on level one,] you’ve got to do a lot of stuff where you’re bent or squatted down. Being able to adjust the [aerial lift] to not hurt your back is a really big benefit. [Our employees] don’t seem to mind working at heights, and we do everything very, very safely with all the safety guards in place.”

Not only can vertical growing enable employees to work more productively, but it also can allow management to realize labor savings, too.

Looking ahead

As the cannabis industry continues to evolve, GreenSeal Cannabis plans to continue improving its vertical growing processes, with Niles noting that “the sky is the limit.”

“There’s no reason it has to stop at six [levels],” Niles says. “We stopped at six for two reasons. One, our ceiling height is 20 feet, so you can only do so much. From a labor perspective, [common aerial lifts] only go up to about 19 feet. Could you do 30 [levels]? Yeah. It’s just an engineering question at that point; it’s not really a question of can it be done? It’s just whether it’s economical for you to do it.”

While GreenSeal Cannabis has “grown up” tremendously within just a few years, Niles admits that the company— and the industry as a whole—is barely scratching the surface of what’s to come.

“If you fast-forward 10 years in this industry, there are things that will become conventional wisdom for operations and infrastructure, that people will say, ‘Of course you should do that, that makes perfect sense,’ but people aren’t doing [those things] today,” Niles says. “That’s why I’m so excited about pursuing [innovation] at GreenSeal. Vertical growing is just a piece of that puzzle. There’s so much unknown about this plant, and every day we’re learning more.”

Zach Mentz is senior editor of Cannabis Business Times (CBT) and Cannabis Dispensary (CD). This article originally ran in the June 2021 issue of CBT.

©hansenn | Adobe Stock

For your greenhouse facility to operate at its best, you must properly plan in advance to ensure that the structure and its components are well-maintained and functioning properly.

Here, you’ll find tips for ensuring adequate airflow, facility cleanliness, evaluating fixtures and shade curtains, as well as a special “lightning round” of miscellaneous tips for additional efficiencies.

Managing Airflow

Air circulation in a greenhouse — a separate concept from ventilation — is best achieved with horizontal airflow (HAF) or vertical airflow (VAF) fans designed for this purpose. Avoid using standard box fans. HAF fans need to be sized correctly for the cubic feet of the air mass and installed in sufficient numbers to make a circular current in your greenhouse. Air has weight, so momentum will carry it with little energy input from the fans once it flows in this pattern.

The total fan capacity in cubic feet per minute for this circulation pattern should equal one-fourth of the greenhouse volume, according to the text “Greenhouse Engineering,” a Cooperative Extension publication by Robert A. Aldrich and John W. Bartok, Jr. Ideally, these fans should be integrated into your control system so that they shut off when the ventilation fans are cooling the room. Otherwise, they will create turbulence that will disrupt the parallel flow across the greenhouse, reducing the cooling efficiency.

The advantage of VAF fans is that they can pull air upwards through the canopy, reducing stagnant air in the lower foliage. Typical installations for cannabis are one fan for an area 30 to 50 feet in diameter (707 square feet to 1,964 square feet). The bottom of the VAF fans should be at least 3 feet above maximum height of the canopy. VAF and HAF fans should not be used at the same time.

Circulation air velocity should be a minimum of 50 feet per minute (fpm). At the very least, you should see some flutter in your leaves at their maximum height and density.

Cleanliness

Keep the walls and roof clean, but don’t have your team clean it. Estimated light-transmission loss from dirty greenhouse roofs ranges from 5% to 10%.

Here’s a scary, but true story: At the university greenhouse I managed for 20 years, I made a policy that no one but me could have their feet higher than 6 feet off the ground on a ladder or scaffolding. This was after being shaken by news that an employee cleaning the glass roof of another university facility was seriously injured when she fell through the glass and landed on the metal benches inside.

I’d recommend hiring an insured, professional greenhouse service team to clean your coverings if you have a large range. For gutter-connected houses, robotic units (which roll along the peaks, scrubbing and rinsing) can be purchased. If you take this task on yourself, rent power lifts and have your staff certified to use them for pressure-washing the glass or rigid plastic, at the very least. Avoid the use of ladders or “walking the gutters,” since there is nothing to tie yourself to for safety.

Clean sidewalls, inside and out, annually. Glass or rigid plastic with heavy scale deposits can be pre-treated with a sulfuric acid product registered for greenhouse use before pressure-washing. For routine glass cleaning, use glass cleaner and squeegees on extension handles for best results. Avoid getting cleaning solutions on plants.

Light Fixtures

Tracking operation hours of your bulbs, either in your written log or using the control computer, will ensure you change them before their output decays below 80% (20,000 to 24,000 hours, typically). An old HPS bulb will often appear darker orange when illuminated than a newer one. HPS bulbs that sporadically turn off every few minutes need to be replaced immediately, before they burn out the igniter in the fixture. Fixtures with loud, buzzing transformers are a true nuisance to your employees, who must work in the room several hours per day. Failing fixtures can be repaired, but only by someone certified to discharge a capacitor and work with high voltages.

Tip-Top-Shape Shade Systems

Employing motorized, shade-fabric systems is an excellent way to regulate light intensity and daily light integral; but these systems are expensive to repair, as the labor costs to make even the smallest fix is several times the cost of the component, especially if you need a power lift to reach it.

Therefore, it pays to buy quality fabric and maintain the system routinely. Buy fabric from established manufacturers. Compare warranties and ask if the warranty is pro-rated — meaning each year the replacement value diminishes — and also ask if the warranty pays you back money or just allows for a discount toward your next purchase. These questions will give you a good idea of who stands behind their products. (Bonus tip: Consider a white fabric designed to diffuse light, as research suggests this will increase the number of photons reaching lower foliage.)

Lube rack and pinions annually with a dry moly aerosol lubricant spray. Avoid grease, as it allows dust and grime to collect and gum-up the gears.

Inspect your curtains to make sure circulation fans are not blowing directly on them. This will cause them to vibrate constantly on the support wires, wearing them thin quickly.

The ‘Lightning Round’— More Tips! Below are more tips — that don’t fit tidily into other categories — for an efficient building and operation:

Consider contracting annual maintenance to an experienced greenhouse company. This resolves the safety issues and allows you and your staff to concentrate on growing and delivering quality product to your customers. It will ensure the maintenance is performed, as these tasks are typically not prioritized, despite best intentions.

The same dry moly aerosol lubricant mentioned for shade curtains’ rack and pinions should be applied to vent rack and pinions annually.

A rivet gun will help you fix loose louvers.

Apply floor coatings to cement, making it resistant to algae buildup. The room needs to be empty and dry to apply the coating, and it takes two to three days for application and suitable drying; but it is well worth it, even if only in your propagation area or under evaporative pads.

Irrigation pipes and hoses should be cleared of biofilms annually, using a product labeled for this use. This will reduce clogging of drippers and nozzles. One method to prevent clogging and biofilm accumulation is to install clean-out valves on the ends of the dripper feed lines to force full-pressure water through every week or so. Some growers replace their drip systems once or twice a year to resolve the biofilm problem.

Label each outlet with the circuit breaker that controls it. I use a labeler with weatherproof, adhesive printing tape to color-code them according to outlets that are controlled by timers (versus those that are always on). These labels will improve safety, communication and efficiency of repairs and installations.

Consider single-table light-deprivation systems for crop-scheduling flexibility. This may help you utilize space more efficiently. I have used excellent single-table systems that allowed us to conduct experiments with differing photoperiods.

Determine the best method to consolidate maintenance and repair records in a format that can be shared with your team and is available by smartphone. Develop your own Google Docs or consider other third-party software.

Use signal tapes and flags to improve communication between staff about a clogged dripper, for example, or which plants have pests or are being flushed, etc.

Make repairs more efficient by maintaining a parts list and keeping spare parts on hand.

Anything made of plastic in a greenhouse, such as a fertilizer injector, should be shielded from direct sunlight exposure to protect them from cracking or disintegration. Reflective bubble wrap is a good solution.

Assemble job-specific tool kits for a grab-n-go response to problems: a kit for plumbing repairs and a kit for electronics repairs. Also, an emergency submersible pump with flexible hose fittings can quickly replace an evaporative pad pump until you can plumb in one properly.

Invest in rolling safety ladders with side rails for reaching high places.

Consider buying a used power lift from an equipment rental company, if you can’t afford a new one. I bought one for $6,000 that has lasted more than 10 years.

Place two 20-gallon trash cans everywhere you currently have a standard 32-gallon trash can. Yes, this takes up more space, but will save your staff back strains when they get overfilled, as the smaller cans hold one-third less material.

Editor’s note: This article was first published in the March 2021 issue of Cannabis Business Times magazine.

Fukume | Adobe Stock

Growers have a lot of choices to consider when selecting lighting systems to produce plants, including efficiency and productivity. Cultivation approach (indoor or greenhouse), technique (single-tier or vertical racking), and cultivar are important factors and can influence which equipment can do the job effectively.

Horticultural lighting is a fast-growing segment of the electric load for many U.S. utility companies, and lighting for indoor cannabis cultivation accounts for much of this growth. The “2018 Cannabis Energy Report,” published by New Frontier Data and co-authored by Resource Innovation Institute (RII) and Scale Microgrid Solutions, estimated that legal cannabis cultivation in the U.S. consumes approximately 1.1 million megawatt hours of electricity annually — enough to power 92,500 homes — and recommended that the industry “evaluate energy-efficient and renewable energy technologies” to rein in its carbon footprint.

The U.S. Department of Energy recommends that growers transition their lighting to light-emitting diode (LED) technology, a move the agency says could reduce electricity usage by at least 40% and save operators approximately $240 million. The industry is poised for the transition; a 2019 Strategies Unlimited report forecasted that the LED market for cannabis will grow more than 300% in the next five years.

Evaluating LED Solutions

Growers who are interested in researching LED technology and looking for unbiased information may want to start with the DesignLights Consortium (DLC), a nonprofit organization with a board of directors that includes leadership from energy and utility companies. The DLC instituted a first-of-its-kind performance standard for horticultural lighting in 2018. The result of two years of stakeholder engagement, the DLC’s Technical Requirements for Horticultural Lighting set standards for efficacy, safety, durability and other criteria that manufacturers must meet to get their LED products included on the DLC’s Horticultural Lighting Qualified Products List (QPL). Currently, listed products are at least 10% more energy efficient than the most efficient legacy grow lights (i.e., double-ended high-pressure sodium (HPS)). The DLC third-party verification process for horticultural lighting does not exist for non-LED lighting solutions like High Intensity Discharge technology (e.g., HPS, metal halide).

The QPL is a searchable, filterable online resource that gives grow light shoppers a map through what can be a confusing landscape of options. With 226 products listed and more reviewed and added regularly, the QPL offers cannabis growers transparent performance data that allows apples-to-apples comparisons of LED fixtures and the ability to verify manufacturers’ marketing claims.

An increasing number of efficiency programs rely on the DLC’s Horticultural QPL for designing energy efficiency (EE) programs for commercial cultivators. Nearly 60 EE programs serving growers in 31 states and four EE programs in Canada require use of QPL-listed products as a prerequisite for EE incentives, and many others have incorporated the DLC Technical Requirements into their programs while not yet requiring listed products. Massachusetts and Illinois, which have cannabis-specific EE regulations, offer use of the DLC Horticultural Lighting QPL as one route for compliance. (The QPL website includes a filter to facilitate cultivators’ search for regulatory-compliant products in these states.)

In addition to efficiency, manufacturers’ longevity and safety claims must be verified for LED fixtures to get listed on the Hort Lighting QPL. Notably:

• Products must be tested at the worst-case electrical scenario. This conservative assessment means that growers who use a listed product at a different voltage may experience better performance than the fixture’s listed performance.
• LEDs must produce a maintained photon output of at least 90% of initial output for at least 36,000 hours — ensuring longer life and lower maintenance costs compared with HPS fixtures.
• Drivers and fans must have a lifetime of at least 50,000 hours, increasing reliability.
• Fixtures must have a warranty of five years.
• Fixtures must be certified by an Occupational Safety and Health Administration (OSHA) Nationally Recognized Testing Laboratory, or Standards Council of Canada (SCC)-recognized body, to meet specific safety benchmarks deemed applicable to horticultural lighting products by that safety organization.

Eighteen months after rolling out its horticultural lighting Technical Requirements, the DLC announced the policy’s first major update in September 2020, scheduled to take effect March 31. This update maintains the current efficacy threshold but adds new optional reporting requirements that extend the performance information to include additional UV and far-red wavelengths, so that in the future the QPL can offer products with more diverse ranges of light recipes. The update also includes use of the ANSI/CAN/UL8800:2019 Safety Standard for Horticultural Lighting Equipment And Systems, which has specific rating requirements for environmental factors such as damp locations, ingress protection codes, photobiological safety ratings, and UV material protection.

The DLC is considering further updates this summer under Version 2.1 that would add three new categories of fixtures to the Horticultural Lighting QPL: DC-powered fixtures, liquid-cooled fixtures, and LED replacement lamps. Look for updates on the DLC’s Horticultural Lighting Program website (designlights.org/horticultural-lighting/).

Bright Questions for Manufacturers

Before growers consider replacing their light fixtures, they should consider creating a baseline of their operation in RII’s benchmarking tool, Cannabis PowerScore, to record their current Key Performance Indicators (KPIs) for energy efficiency, productivity and lighting performance so they know how their operation is performing with their current lighting technology. As they upgrade their lighting systems and potentially transition to LED solutions, they should continue to benchmark their facility periodically to quantify the benefits with PowerScore, verifying the improvements in their KPIs to measure their success.

RII’s analysis of aggregate PowerScore data shows that indoor cannabis cultivation operations growing with LED for flowering achieve 34% better average electric facility efficiencies and 80% better average electric production efficiencies than indoor facilities using double-ended (DE) HPS lighting for the flowering growth stage.

Growers who are ready to evaluate lighting solutions and the manufacturers serving their market should ask suppliers:

• What is the warranty of your product?
• What is the rated fixture life and control equipment life? What tests were performed to validate the claim?
• Has your product been tested on my cultivar(s)?
• What is the spectral quantum distribution (SQD) of your product, and does it align with my desired light recipe?
• Can you provide Photosynthetic Photon Intensity Distributions (PPID) to show the photosynthetic light emitted at different angles so I can plan lighting layouts? (The PPID allows you to create your own lighting plans rather than relying on the manufacturer.)
• What technical assistance is available during the design phase for lighting plans?
• What help can you provide if I encounter problems during production?
• Is there a cost for technical support or limitations on when/how to access it?

When growers ask suppliers about LED lighting solutions, they should verify whether the products are DLC-listed. Growers can note that SQD and PPID images are provided for LED products on DLC’s Horticultural Lighting QPL. If a product is DLC-listed, cultivators can ask the manufacturer about their experience getting help from utilities with rebates to buy down the first cost. In 2018, the average cost of flowering LED fixtures was around $1,500 compared to conventional HID lighting solutions like HPS, which cost around $500 on average in 2018 and have continued to decrease in price faster than LED products, according to market research completed by RII member Energy and Resource Solutions. First cost of LED products can be a barrier to adopting this emerging technology.

©Gleti | iStockPhoto

Measuring LEDs Effect on Plant Expression

A challenge of using LED horticultural lighting can be understanding how it stimulates plant responses like photosynthetic action and secondary metabolite production. Predictive metrics like PPF or photosynthetic photon efficacy (PPE) are, as the names indicate, based on light-stimulating photosynthesis.

The metrics used by RII, DLC, fixture manufacturers and others are standardized by the American Society of Agricultural and Biological Engineers (ASABE). These metrics do not predict light’s ability to produce other responses, like the production of specific secondary metabolites such as CBD, THC and terpenes.

In the U.S., research organizations are studying hemp production, sometimes in collaboration with lighting manufacturers, and publishing results for different spectral combinations and light amounts. At this time, no metrics considering the interactive effects of spectrum and dose on specific secondary metabolites have been proposed.

RII and DLC hope that additional metrics will begin to be considered and developed, so that cultivators can better predict which lighting system is going to help them optimize the biological results. In the meantime, the industry continues to use photosynthetic metrics and empirical data to inform additional desired outcomes.

Improved facility efficiency and productivity are possible with LED horticultural lighting solutions, as they save energy, while more non-energy benefits are yet to be researched and quantified. Tested and certified LED products on the DLC QPL can be relied upon for cultivation, so growers should consider the variety of trustworthy options on the DLC QPL when they make their next lighting purchase.

Anticipating and Overcoming the LED Learning Curve

Another challenge of using LED horticultural lighting can be navigating the learning curve of LED technology and modifying Standard Operating Procedures (SOPs) when necessary. There are a few considerations during design and construction that can optimize grow environments to be adaptable and successful as growers use their new equipment, and peer-reviewed guidance is available to help them maintain productivity. RII’s LED lighting best practices guide offers tips for successful installation and operation of LED products. RII’s Massachusetts best practices guide offers tailored recommendations for a market that is adopting LED lighting. Download both guides at ResourceInnovation.org/Resources.

This article first appeared in the January 2021 issue of Cannabis Business Times magazine. Gretchen Schimelpfenig, PE, is the Resource Innovation Institute’s (RII) Technical Director and manages the organization’s Technical Advisory Council. Leora Radetsky, MS, LC is Senior Lighting Scientist at DesignLights Consortium.