Marijuana Business Magazine July 2018

still overwater, resulting in resources going down the drain. The consequences of “drain to waste,” as the practice is known, include higher water bills and environmental dam- age to streams, ponds and other water sources that become contaminated by wastewater runoff. “If you’re draining to waste, you’re spending way too much money and your company is going to go downhill,” said Casey Rivero, cultivation manager at Yerba Buena in Oregon. Get to Know Your Plants To avoid wasting water, Rivero starts with “a lot of tissue, soil and produc- tion analyses.” He and his team perform plant tissue analyses to know how much moisture different cultivars contain.They also track the health and look of the plants to know how much water each cultivar likes to drink. For example, Rivero now knows that the company’s Do-Si-Dos indica strain takes 30%-35% less water than Pine- apple Express or Silverhawk. “ Paying attention is key,” Rivero said. “Each cultivar has its own needs. We don’t feed all our cultivars the same exact amounts. We use drip systems in flowering rooms and can dial in specific gallons per minute on each type of plant. So, when we set up our rooms, we know which plants like to feed more, and which ones less.” “We give our plants the exact amount of water they need and nothing else. There is no draining and wasting, there is no water runoff,” Rivero added. “That’s a part of cost control that a lot of people need to pay attention to. A few more gallons here, a few more milliliters of nutrients there – that adds up. Over a year, you’re at $15,000, $20,000.” Choose a Drip System Carefully If you do plan to get a drip irrigation system, growers note, make sure it can handle organic nutrient mixes. Synthetic mixes don’t clump, but organic ones do, mean- ing they can clog drip lines. “There are more effective drip systems but never a plug and play,” Rivero said. “We’ve redesigned our drip systems and our watering systems four to five times now, based on how they’re working, and new concepts that we come up with to make our program more efficient.” Recycle Your Runoff Some growers do allow a small amount of runoff, which they then capture and reuse. Oregon-based cannabis cul- tivation consultant Eli McLean allows about 3%-5% runoff, which he captures and then sends through a filter he is developing. “That water has lots of nutrients (and) pH balancers; that’s not good for waste treatment plants,”McLean said. “We trip out those nutrients and reclaim that water.That’s another water source you’ve stopped from going out of the building.” Other businesses send captured runoff water through a desalination process that alternates cycles between water purifica- tion and water recovery. McLean said the process is nearly “100% efficient,” meaning it eliminates contaminants with almost no water waste. One water-purification method McLean rejects is reverse osmosis, a process he said takes about 3 gallons of water to clean and reclaim 1 gallon. “That’s not efficient,” he said. Capture Condensation Another way to conserve water is through water con- densate that comes from heating, venting and air-conditioning (HVAC). McLean likes the gPod from Data Aire, a company that provides cooling solutions for the data center industry and recently moved into cannabis. Here’s how it works: Heat that is usually sent to condensers and then vented into the atmosphere is instead rerouted through a dehumidification coil.The coil warms up and induces condensation from humid air that is also running over the coil. McLean said a 10,000-square-foot room with 10 units working to cool and dehumidify can result in hundreds of gallons of water recovered from the air each day. “It amounts to a sizable water sav- ings,”McLean said. And, he noted, because that water is being retrieved from the air, it’s basically free of con- taminants found in runoff or city water. Still, a company can run it through a filter in case any airborne contaminants like mold spores made it into the water. “Many people used to put that conden- sate right down the drain, which is waste- ful because it’s fresh water being wasted,” McLean said. “That is water you can use in your grow.There’s nothing in that water. It’s as clean as water can be.” We give our plants the exact amount of water they need and nothing else. 2 3 4 5 SUSTAINABLE CULTIVATION 76 • Marijuana Business Magazine • July 2018