For every crop in the United States, the Environmental Protection Agency carries out a rigorous set of tests to determine which pesticides are safest. How and when a pesticide is used can depend on how that crop is consumed by the average person — is it ingested, inhaled or applied topically?
It’s a precise science that aims to keep consumers safe from potentially toxic residues, of course like most federal regulations, none of it applies to the marijuana industry.
In lieu of government research, a state with legal marijuana, like Colorado, is left to develop its own set of rules. That can leave cannabis growers largely on their own. Whitney Cranshaw, an entomologist at Colorado State University, says many marijuana growers look to the internet for best practices.
“In terms of pest management advice, I have never seen so much gross misinformation so much junk science,” he said.
As an extension specialist at CSU, Cranshaw developes pest management programs for horticultural crops, but because cannabis is still federally illegal, he can’t touch it.
“It drives me nuts,” said Cranshaw. “(I) could make more progress in terms of helping people by providing information on these crops (…) than anything that I’ve ever worked with.”
In Colorado, state officials have used existing EPA research to create a list of which pesticides marijuana growers can use. They’ve selected more than 300 products that are so low in toxins — many of them are organic — they don’t leave behind harmful residues. And their federally regulated labels allow them to be used on virtually any crop.
Still, some growers are caught using pesticides they’re not supposed to.
Inside a warehouse near downtown Denver, Cynthia Andersen walks along rows of marijuana plants. Fans gently oscillate under blaring white lights to create a synthetic