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Greenhouses are no longer the speculative future of cultivation— they’re the present. As companies scale, and as flower prices fall, greenhouse growing has become a practical ‘must’ for staying competitive in the cannabis industry. The move to high-tech greenhouses dramatically decreases electrical energy costs and improves overall facility efficiency when compared to indoor cultivation. As reported by Marijuana Business Daily in 2017, growers estimate greenhouses reduce operating expenses by about 25%.
Historically, cannabis has not been a greenhouse crop — prohibition required secrecy. More recently, steep capital costs have kept cultivation indoors, and the technological challenges of expansion have not helped either. Greenhouse-grown marijuana carries a reputation for lower quality, in part because of environmental control issues not present indoor. It’s a dramatically different growing paradigm. In a greenhouse, heat management becomes cumbersome, pest control gets harder, and managing workflow is more complicated. The techniques that worked well for indoor probably won’t scale— a top-down reassessment is in order.
Creating a sustainable grow by using a greenhouse can be challenging, but, if there weren’t upsides and solutions to the problems, greenhouses would be a growing method of the past. Yet, crops like tomatoes, cucumbers, and bell peppers, which are actually more pathogen-prone than cannabis, thrive when grown in a greenhouse. For example, with a total greenhouse footprint the size of Manhattan, the Netherlands produces tomatoes at five times the yield per square foot of any other country. What’s more, they’ve largely eliminated pesticides with integrated pest management protocols.
“The technology for everything we do pretty much already exists; you just have to find [it] and then apply it to this industry,” says Bruce Granger, Managing Partner at FlexMod Solutions, a manufacturer of modular facilities and provider of cultivation system design.
Given the high value of cannabis crops, it makes sense to maximize every opportunity those technologies can provide. In this article, cultivation system designers and greenhouse manufacturers weigh in on the latest technology and share four tips for reaping the most from your proposed facility.
1. Have a Plan for Winning the Battle of Humidity vs. Heat
Newly converted greenhouse cultivators find the task of regulating temperature swings to be surprisingly difficult— especially when relative humidity increases at night.
“It’s difficult to achieve the target conditions you’re after,” explains Kurt Parbst, Director of Business Development at EnviroTech Cultivation Solutions. “You have this feedback loop.”
As Parbst explains, unlike an indoor grow room, a greenhouse has minimal insulation against cold temperatures. And unlike an indoor grow, it receives significant solar energy during the peak heat of the day. Balancing day-to-night temperature swings becomes a must, yet the greenhouse design team at EnviroTech finds the difficulty of doing so surprises many growers, particularly at night. Their solution to the heat/humidity problem relies strongly on humidity control.
Parbst describes the cycle of temperature/humidity imbalance like this: nighttime temperatures drop, so the facility needs heat, which causes transpiration and increased humidity. The usual technique for nighttime heating and humidity regulation (heating the greenhouse while simultaneously venting) is possible because of inexpensive natural gas. But bringing in cold air can chill and therefore wet the plants prompting more heating, and more heating means more transpiration and vapor within the canopy. The balancing act makes maintaining target nighttime conditions tricky and energy intensive. EnviroTech’s solution is to close the greenhouse during the dangerous night hours and actively dehumidify with a liquid desiccant.
“We can solve this by keeping the heat in the greenhouse and absorbing the humidity. By keeping everything closed—the curtains, the vents, the fans off—you’re not bringing cooling in from the exterior. Because you’re reducing the heating, you’re reducing the transpiration, so it makes it easier to dehumidify while maintaining a steadier temperature profile,” says Parbst.
EnviroTech works with Agam, an Israeli company, whose dehumidification technology uses a desiccant salt to strip moisture from the air and reduce airborne pathogens. Closed greenhouses—or semi-closed greenhouses—run cleaner than ventilated ones, but Parbst doesn’t recommend 24/7 closure.
“A greenhouse is a solar collector and absorbs a tremendous amount of solar energy. Unless you have some way of removing that heat energy, cooling becomes a huge energy expense,” notes Parbst, who also cautions that closed greenhouses are most beneficial for companies selling air conditioners.
For those seeking the isolation and control of a closed greenhouse, he advises to “use the insect exclusion that’s on the market—combined with biological controls— integrated pest management has advanced quite rapidly in the last fifteen years.”
2. Reap Automation Benefits and Seize Big Data Opportunities
Your transition into larger (or newer) facilities will likely come with some next-generation equipment. Accordingly, the software side of things will advance to match. A multi-acre facility employs a major environmental control system and significant automation because, at such a scale, mechanization eclipses human attentiveness. While the insight of growers remains irreplaceable, machines are able to reduce error and regulate processes better than people. If they’re not already doing so, computers will likely be running your next facility, and they’ll be doing more than just irrigating and turning on lights.
Control systems can now estimate when to water based on the accumulated light and the vapor pressure deficit in the canopy, as well as mix fertilizers in response to changes in the pH and electrical conductivity (EC) of the growing medium. Responsive monitoring and control systems can help balance interdependent factors like heat,humidity, and measurements of external light levels that integrate into the lighting plan. However, a controller’s ability to respond to adverse conditions and mitigate risk often proves most valuable.
“It’s important to not just look at the control system’s ROI but also to look at opportunities lost and preventing those,” says Brad Nattrass, Chief Executive Officer at urban-gro. “We’ve identified that risk mitigation is the key component in that ROI factor.”
urban-gro offers cultivation solutions for cannabis growers by expertly vetting cultivation equipment and implementing control systems for greenhouse grows. But, soon, urban-gro will introduce the most extensive sensor and feedback system on the market: Soleil® Sense.
Soleil® is the Internet of Things for controlled environment agriculture. The system will use wireless sensors at the base of each plant, in addition to other strategic locations in the growing space, to measure temperature, humidity, and barometric pressure. An accelerometer is also present to indicate whether individual plants have been disturbed or serviced. urban-gro’s future iterations of the technology will include measurements for soil moisture, pH, EC, and light levels. What makes the system unique is the tremendous scale possible with the wireless sensors. Tens of thousands of sensors can be incorporated, making its application practically limitless. With such a dense concentration of sensors, the Soleil® system offers penetrating insight into the distinct microclimates and problem areas throughout the facility.
“It’s a granular, higher-resolution insight into what’s going on in the facility,” says Steve Wilchek, one of urban-gro’s system engineers. “Essentially, each plant is a pixel, and if it’s not a perfectly uniform screen, that’s exactly where they’re going to send somebody to look. They’re able to spot an issue as it’s happening, and solve it, as opposed to waiting for a harvest yield report to determine what went wrong.”
urban-gro offers the Soleil® system on a hardware-as-service basis, along with an analysis of the resulting data. Throughout the diurnal cycle—and the overall lifecycle of the plant—the sensors give feedback that optimizes control capabilities while reducing risk.
“We’ve had a grower realize that they had conditions—in just certain areas of their facility—that were conducive to pests. We were able to put in an airflow fan plan to eliminate those dead spots in their operation and decrease their chances of infestation,” Wilcheck continues.
Beyond the system’s risk mitigation features, the folks at urban-gro are excited about the possibilities created by all the data the Soleil® system collects. Until now, the conditions and outcomes of greenhouse grows have been hard to compare with one another, hampered by changing seasonal conditions and strain variations. But with such a wealth of data, urban-gro expects cultivators will be able to better assess their results with particular genetics and improve outcomes.
3. Plan Your Greenhouse Layout to Lower Your Payroll
Another surprise that comes with a larger facility is, ironically, its size. Growers underestimate how labor practices will need to change in order to make the plant-to-plant commute manageable for personnel. The workload intensifies when repeatedly moving materials long distances for transplanting, trimming, spacing, and trellising.
“We designed a facility where we had a 100,000-square-foot headhouse supplying ten 30,000-square-foot greenhouses,” says Granger. “And we connected them all with conveyor belts inside of tubes. They did all of the vegging in the headhouse, and then moved the plants out to the greenhouse for flowering. When they were harvesting, we just ran the conveyor belts in reverse (back to the headhouse).”
FlexMod has found that natural light is most important during flowering, so they design facilities that move the vegetative operation indoors, in order to save greenhouse space. By using vertical growing techniques, and transporting plants, they achieve a plant density not possible in a greenhouse. With a retrofitted headhouse, FlexMod can expand an operation considerably without a proportionate expansion of its footprint. Plants-to-people technology helps make that possible.
“You can have a very labor intensive greenhouse or a very efficient greenhouse,” says Parbst, whose company also proposes centralized workspaces. “To me, the biggest labor saving benefit is good plant flow: getting plants to workers rather than getting workers to the plants. If you have fixed locations for all the plants, it means you have to walk from the entry point to each plant. So, we design plant transportation systems to move many plants at a time into their appropriate light and irrigation environment and then back to the workstation.”
Parbst claims a ten-fold reduction in cultivation staffing with EnviroTech’s plant transportation method, yet growers can still be hesitant to abandon their old ways of operating despite the technology’s use in other industries.
“We ask them [clients] how many people they’re thinking about employing, they say 150. Flower growers would do this with 15,” says Parbst. “You’d need a full-time HR department.”
Monitoring systems, like urbangro’s Soleil® Sense system, can also boost operational efficiency. With better insight into where problems are occurring within a facility, labor can be deployed more effectively to those areas. And by placing sensors on equipment, urban-gro can offer predictive maintenance, which streamlines labor implementation while simultaneously reducing risk.
“The Soleil® tech allows us to put a sensor on every fan and HVAC distribution, and they’ll be able to sense when the vibrational frequency is off,” says Nattrass. “Having a fan die out or operate at 50% capacity can throw off everything in that area of the greenhouse. The Soleil® system is a predictive maintenance tool.”
4. Approach the Planning Process Wisely, Step-by-Step
A new facility doesn’t arrive with a bow; it’s an extensive process that starts with real estate acquisition and ends when the lights come on, involving a multitude of designers and contractors to get involved along the way. EnviroTech Solutions offers packaged services that include design as well as construction project management.
“Timing is the first thing to know—the planting date,” says Parbst. “Then it comes down to location.”
After designers establish a timeline, they assess the property’s area and topography to orient the greenhouse properly. Orientation is particularly critical in maximizing solar exposure and avoiding the shade caused by the partitions within the greenhouse or poorly placed auxiliary facilities.
“Then we start looking at what the design conditions are for the [geographic] area; what’s the ambient light, what’s the temperature, the humidity, the wind in the area, snow, what are the seismic requirements, the soil conditions,” says Parbst. “From there we move into the superstructure needs. A greenhouse is the scaffolding that supports all of the environment-correcting equipment. But it’s related back to the location—what are the regional loadings for the wind and snow, available light, and temperature norms.”
“The next phase of analysis”, according to Parbst, “is the interior [and] all the environmental equipment that goes inside. Those are categorized into the conveying systems, water systems, and HVAC. It also includes greenhouse specific technology like insect exclusion, the curtains that will be used for creating short days. Then we look at the electric system, which is basically lighting, instrumentation, and controls.”
“We look at the utilities that are available and sometimes the [electrical] grid is insufficient. You may have to look at some sort of onsite generation. And also what’s the availability of heating fuel. You need a ready source of natural gas, ideally, or else you have to look at propane as a second source,” Parbst offers.
The process spans months of planning, permitting, and coordinating of contractors. An operational facility may be over a year away from the inception date. Some alternatives to a full, ground-up greenhouse exist, including the plug-and-play solutions offered by companies like FlexMod. The small units utilize a shipping container as a grow module and, while not a greenhouse, they can be a quick substitute to the extensive design process necessary otherwise.
“We can get you a shipping container within six to eight weeks, and once it arrives you’re ready to start growing,” says Granger. “Some states require that you be operational in six months from the date you get your license., and some don’t care whether you’re growing 700 pounds or six ounces. With a shipping container, you can have a crop in four months and put a check in that box.”
Modular units can solve planning problems and offer benefits when retrofitting as well. For additions to existing facilities, Granger designs and supplies the walls which are easily assembled onsite. “They snap together like Legos,” says Granger. “And at the end of the day—when you end your lease on your property—just like Legos, you can unsnap them and take it with you.”
Regardless of your facility and aspirations, work with an expert. Just because you have an excellent cultivation team that has implemented environmental systems planning in the past doesn’t mean things will go smoothly when working at a dramatically different scale. A greenhouse is a long-term investment with high capital costs, so it makes sense to take the time to maximize your facility’s production capacity. Employing experienced designers, agronomists, and project managers will pay dividends in the future.
“Proactively spend the time and money to set it up properly,” says Nattrass. “You’ll save yourself a heck of a lot of heartache and pain in the future!”
For more information about greenhouse optimization and design or to meet with FlexMod Solutions, urban-gro, and EnviroTech Cultivation Solutions, attend NCIA’s Seed to Sale Show February 7-8, 2018 in Denver, CO.
Or call (888) 409-4418 to Register.
Register by January 5th to save $300+
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Jack Bohannan writes technically oriented content marketing materials for cannabis cultivation and extraction products. He lives in Denver, Colorado.