At Colorado Harvest Company, one of the state's largest marijuana businesses, pot is grown in coco fiber rather than soil, a substance with no nutrient value. Why? Tim Cullen, the company's CEO, said that allows them to closely monitor all the nutrients going to the plant, all delivered through water.
"We never let water run out of these plants, and if you look in these trays, they're designed to hold water in them," says Cullen. "We don't want any water to run out of the bottoms of the plants because that's just wasted nutrient."
With the legalization of marijuana in various states and forms, conservation groups and others are asking how much legal grow operations affect water consumption. Water managers and researchers in Colorado are working together to answer that question.