Marijuana Business Magazine September 2019

Marijuana Business Magazine | September 2019 140 It’s smart to filter out any contaminants, but if the water is tested regularly (at least once each quarter), a cultivator can create a nutrient mix that incorporates some of the naturally occurring minerals in the water. Just reach out to a local laboratory to have your water tested. “I have grown with municipal tap water and done just fine,” Bravmann said. A grower using rainwater can rely on the soil to provide a buffer in the way that a hydroponic medium doesn’t, he added, which will help mitigate or break down any unwanted minerals or contaminants. “Most people will say rainwater is pretty good water,” Bravmann said, though he admits large-scale cultivators will want to remove any variability from the water supply. If a cultivator really wants to create a consistent, reliable irrigation system, Bravmann recommends that any grower who can’t use rainwater buy a reverse osmosis (RO) system, which removes contaminants from water by forcing it through a porous membrane. “That’s the one way to guarantee uniformity,” he said. “RO water is about the same in Portland as it would be in Colorado.” While Bravmann admits it can be a little wasteful—as you pull the particulate out, you lose water volume—RO creates a blank canvas to work on. Reverse Osmosis At Desert Grown Farms in Las Vegas, which is owned by Green Thumb Industries, Director of Cultivation Alessandro Cesario filters his water three times. The city of Las Vegas’ water has a comparatively high number of dissolved solids and other unwanted elements, so he runs it through a HEPA filter to block any large particles, a carbon filter to trap the chlorine and two RO machines for purification. Cultivation facilities equipped with reverse osmosis systems can create uniform irrigation water regardless of location. Photos Courtesy of Green Thumb Industries Best Practices In Cultivation | Bart Schaneman