Cannabis growers who can grow their crops to their desired quality and yield targets using fewer inputs (i.e., grow at a lower cost) than their competitors have a competitive advantage in their markets. And should the U.S. Food and Drug Administration approve cannabis for interstate commerce under federal rescheduling, competition would only get stiffer.
That’s why it’s important to take a close look at key systems such as lighting and irrigation to determine what, if anything, can be optimized to minimize potential waste and increase efficiency.
Here, we offer tips and best practices to help you grow a climate-smart cannabis business built for longevity.
Lighting
Lighting is one of the most significant operational expenses in cannabis cultivation, making it a prime area for resource-efficient and cost-saving initiatives. By optimizing lighting systems, growers can reduce energy consumption, improve yields, and ultimately boost profitability.
Mikhail Sagal, a contributor to Resource Innovation Institute’s (RII) Lighting Best Practices Guide and president of TSRgrow, an RII-member organization, says that the first thing cannabis growers need to do on their optimization journey is track their energy usage. Too often, growers set up their lighting systems without ongoing verification, leading to missed opportunities for improving efficiency.
“There’s rarely any ongoing verification or checking of lighting equipment efficiencies,” Sagal says. “Monitoring energy is very important.”
He stresses it’s essential to track not only overall energy use but also the energy consumed for specific strains and growth cycles. This data allows growers to assess how efficiently they’re producing each pound of cannabis.
Ideally, growers can submeter their light fixtures to get a granular view into cultivation rooms and specific zones within each chamber. Centralized powered horticultural LED lighting systems come with integrated energy-monitoring capabilities, which allow growers to track energy usage per fixture without additional hardware. These systems often provide data on energy consumption, light intensity, and operational hours via cloud-based platforms or local software.
Once a baseline power reading has been established, growers can begin experimenting with light dimming (if the systems have that capability). Growers can define light intensity settings and fine-tune them based on the needs of each strain and the environmental conditions in the grow room. This ensures growers only use the light needed to optimize plant health and productivity without wasting energy.
Sagal explains that not all light fixtures will have the same efficiency rating as they are dimmed. Fixtures with centralized power can maintain efficiency even at lower output levels. Centralized power units manage electricity for multiple lighting fixtures throughout the facility.
“They can take in a high voltage AC, essentially 480V, 3-phase, and then distribute the converted DC power to the fixtures with a much higher conversion efficiency that is higher throughout the dimming range,” Sagal says.
Optimizing the light spectrum for each cultivation stage can also reduce energy usage by only delivering the light needed at each growth stage. For example, red and far-red light is less energy-intensive to produce than blue light. Fixtures don’t necessarily require tunable spectrum capabilities. Rather, growers need “a really good spectrum,” Sagal says. “In cloning, you’re going to have much more blue and green and white, but very little red.”
As the crop matures, the lights should slowly add more red spectrum, with far-red light added later in the flowering stage. “Our testing shows that a fixed far-red spectrum at the correct ratio to deep red works extremely well, maximizing cannabinoids, yields and terpenes,” Sagal says. Recent research into far-red is yielding even more insights into its benefits and when to use it in the flowering stage.
Beyond energy-efficient fixture features, growers can stage lights, HVAC systems, and other equipment to avoid simultaneous start-ups that can significantly reduce peak demand charges. Many states calculate energy rates based on peak demand over short periods, making it essential to spread out energy-intensive activities across the day. This can lead to major cost savings, particularly in regions with high peak demand charges. “You can stage the lights and the rooms even by minutes so that you never maximize a peak demand,” Sagal says.
Additionally, many utility companies offer incentives through demand response programs, where growers can be paid (or receive a credit) to reduce energy usage during peak grid demand windows—typically when residential users draw the most power from the grid. By integrating lighting controls with these programs, growers can reduce energy costs while contributing to grid stability, making them both eco-friendly and economically savvy—another reason why data logging is important.
For growers noticing uneven growth in their crops (e.g., where lower branches have significantly less inflorescence), subcanopy lighting can be a less energy-intensive solution compared to increasing light intensity or adding more overhead fixtures.
“Intracanopy lighting allows you to get more uniform growth deeper in the canopy, resulting in bigger buds at the lower levels,” Sagal says. This approach can be especially useful in vertical farming setups common in the cannabis industry.
Irrigation and Fertigation
Water and nutrient management are other key cultivation inputs that are ripe with efficiency improvement opportunities both at the beginning of a new buildout or as fertility and irrigation strategies change. Water management may not be a key consideration for growers depending on their location, but as water increasingly becomes a scarce commodity, more and more growers will need to find ways to meet local, state, and federal water efficiency standards.
Similar to lighting management, a better understanding of a facility’s water usage is a good first step to identifying areas where water can be reduced, recirculated, and recycled. For example, monitoring runoff (leachate) volume can reduce waste.Jared Babik, national project sales manager at Dramm, an RII member organization, says, “If you’re shooting for 25% runoff, could you cut that back to 15%, 10%, or 5%? This saves water and fertilizer and ultimately money.”
Testing runoff for nutrient content also can identify opportunities to fine-tune nutrient recipes to only deliver the elements the crop needs when it needs them. “Having an understanding of what you’re putting in versus what the plant’s using … there’s a possibility for savings in that manner,” Babik says.
While some craft growers are great at relying on their feel and experience to determine how much irrigation a specific plant needs, good irrigation practices at scale are rooted in understanding the plant’s water needs based on container size, media type, and environmental factors like transpiration rates. Babik has similar conversations with growers scaling from a few hundred plants to operating with thousands of plants. Ultimately, automation and controls are required.
“What’s most important is that the grower understands how their equipment works,” Babik says. “The equipment and controls used to deliver water to plants should be thought of as an extension of what the grower used to do day to day but on a large scale. It’s the grower’s job to tweak what the system does automatically to maximize the potential of the plant.”
Another hurdle Babik sees growers hit is when converting to drip irrigation while using organic fertilizers. Organic fertilizers are harder to integrate into automated systems due to solubility issues and potential equipment fouling. Organic fertilizers can be used, but growers need “to understand how those ingredients interact with the automated equipment,” Babik says.
On that note, maintaining irrigation lines is crucial to maximize crop production efficiency. Clogged emitters can cause sections, or even entire rows, to go without adequate amounts of water. One common culprit is biofilm.
“Biofilm will grow in every pipe over time, even with high-quality water,” Babik says. Biofilm not only fouls mechanical systems but also harbors pathogens that can be detrimental to plant health, increasing the risk of disease outbreaks or water stress in a grow operation. Regular line flushing and cleaning are necessary to prevent biofilm buildup and extend the life of the irrigation system.
Growers should regularly flush large and medium pipes, as well as lateral lines on benches, and ensure that each part of the system is cleaned in stages. Babik says using additives and sanitizing agents to break down biofilm is appropriate, but growers should avoid allowing debris to enter the smallest components, like emitters.“You can’t just send a cleaner down line when flushing … you’ve got to clean your big pipes, flush it, clean your medium-sized pipes, flush it, and so on,” he says.
Automation systems can be programmed to regularly flush irrigation lines with clear water or additives to prevent stagnation and biofilm growth. Growers can schedule daily or weekly flushes to ensure clean water is ready for the next irrigation cycle.
“You can program a fertilizer injector to stop feeding and send clear water that might have some type of additive in it so that it’s cleaning or sitting overnight,” Babik says. “With controls and solenoid valves, you can easily automate line cleaning without harm to your plant’s roots.
“I’ve seen a couple of growers who’ve got their system so lean that they’re flushing their pipes with water and the last five seconds are through the dripper with clear water. And then the next morning they use a dump valve in the grow room to purge the clear water before feeding the plants with only a couple of milliliters of clear water that goes to the plant.”
Another critical water system that many cannabis growers use is a reverse osmosis (RO) system. RO units strip water of all its elements, giving growers a blank canvas on which to create their nutrient recipes, but they can also be energy-intensive and wasteful, often resulting in significant water loss. Before investing in RO systems, growers should conduct horticultural water tests to determine their water quality and then ask whether these are needed to grow healthy plants.
Lastly, HVAC condensate water can be a potential source for reuse. “While the water may be clean coming off the units, the piping it travels through will accumulate biofilm,” Babik says. A well-designed water infrastructure system can collect, treat and reuse condensate water. “It’s important to understand what’s required to eliminate the bioload and remove 100% of the potential heavy metals in the water,” he says.
As the cannabis and broader CEA industries evolve, future innovations like real-time nutrient monitoring will further improve efficiency, but the basics—good irrigation practices and smart water management—remain key to long-term success.
Robert Eddy, M.S., is a resource efficiency horticulturist at the Resource Innovation Institute (RII).
Resource efficiency isn’t just about being a good environmental steward; it’s also about growing a climate-smart business built for longevity. Read More