Marijuana Business Magazine | August 2019 120 The system Haupert uses is similar to Kimmel’s greenhouse setup in that it uses natural plant oils to neutralize the odor for outdoor and greenhouse grows. The broad-spectrum blend of plant oils she uses is intended to neutralize odors across a variety of different strains. “You’re not talking about one or two chemicals that come off of them,” Haupert said. “There is defi- nitely a large mixture of chemicals coming off.” The odor-control system is set up as close to the vent on the outside of the greenhouse as possible. “You have to make contact with the odorous molecules if you’re ever going to have any chance of actually removing those odors,” Haupert said. Her unit is either wall-mounted or sits on a stand above a 55-gallon drum, depending on how the cultivation operators configure their canopies. This is connected to vapor ducting where the plant oils combine with the cannabis to neutralize the smell. Haupert agrees with Statzer that it’s necessary to use more equipment than just carbon filters. “It’s not that carbon filters don’t do anything,” she said. “But they don’t get all the odors that come out.” Impact on the Grow Environment Kimmel’s carbon filters don’t affect the temperature or humidity in the room, but they can have an impact on air flow. The later the plants are in the flower cycle, the more pungent they become, therefore more odor mitiga- tion is required. “If you’ve got flower that’s seven weeks in, the smell is overpowering,” Kimmel said. Statzer said the same for his grow operation. He emphasized that air circulation is important for efficacy. “You’re going to run it when you’re harvesting, when it’s the worst,” he said of his air-purification system. “As that flower matures, it’s letting off more terpenes.” While Haupert emphasized the importance of making contact with the odor molecules, she stressed that outside plant oils should never touch cannabis. “You never would want your odor-control product to come into contact with the plant,” she added. Other Building Factors Aside from the filters and plant-oil products, it’s essential the grow facility is correctly constructed. “Everything’s got to be airtight,” Kimmel said. He pointed out that cultivators will want to ensure the corners, cracks and doorjambs in the grow are sealed to prevent gaps that could allow odors to escape. “If you’re pulling in air conditioning and exhausting air, you’re creating different pressure zones, and the air’s going to want to suck in from those areas,” Kimmel said. Statzer agreed, saying that entryways are key places to monitor. “You want to make sure you have your doors constantly closed, so you’re not spreading that odor,” he added. Statzer said growers should even consider putting a filter on the bathroom fan. “Cannabis is definitely a fun challenge,” Haupert said. Todd Statzer is the director of environmental sciences for Urban-Gro. Courtesy Photo Best Practices In Cultivation | Bart Schaneman Urban-Gro uses the Element Air PHI wall-mount tower, HEPA filter and carbon-filtration system to create a trilogy of microbial and odor control. Courtesy of Yerba Buena Bart Schaneman covers cultivation and extraction for Marijuana Business Magazine. Reach him at [email protected] .