Going Green: Pot Growers' Worries About Pesticide Use Bloom

Vendors who grow sustainable cannabis display their plants and buds at the first annual Cultivation Classic in Portland, Oregon, on April 30. Winston Ross for Newsweek

Josh Khankhanian stuck his nose deep into a jar of dense, multicolored marijuana flowers on Saturday and cracked a broad smile. The pot was pungent, and this grower from Mendocino County, California, can consider himself a connoisseur after three years on the job. But what was especially pleasing about this particular sniff is that it was of flower grown on a southern Oregon farm owned by Elizabeth and Nick Luca-Mahmood that could hardly be more sustainable, its plants raised on a nearly closed-loop farming method that battles pests and disease not with insecticides and herbicides but diversity—specifically, diversity in poop.

"There are a lot of cannabis growers still using old procedures," Khankhanian told Newsweek. "This is better."

Khankhanian was among hundreds who attended an inaugural "Cultivation Classic" in Portland, Oregon, on Saturday to learn more about a practice that isn't nearly as widespread as it should be: sustainably grown marijuana. While there's not much quantitative data or research available today about it (thanks largely to the federal ban on cannabis and the resulting chokehold on marijuana research) weed aficionados say there's a lamentably large amount of flower grown today via wasteful, water-guzzling and energy-heavy methods, pesticide-drenched plants or, worse, both.

"People should be very concerned about pesticides," says Jeremy Plumb, a grower and dispensary owner who co-sponsored Saturday's event. "There's no long-term research about what the effects are from people ingesting these compounds into their bloodstream. We know from extensive testing that these pesticides show up frequently, way more often than they should."

Cannabis farmer Josh Khankhanian gets a whiff of marijuana grown with a “no-till” method at Saturday’s “Cultivation Classic” in Portland, Ore. Winston Ross/Newsweek

That's largely because it's perceived as cheaper to grow that way, even if that's not necessarily true. Those new to the industry mistakenly believe they'll see higher yields with pesticide use, and that they might not be able to pass along the costs associated with a more expensive-to-grow product to an unappreciative consumer. But the reality, say Plumb and others, is entirely different. "The organic process actually yields more and costs significantly less to manage," Plumb says. "But there are unknowns and variables with organic that make farming way more complex."

Therein lies the problem. Because cannabis is federally prohibited, growers can't even attempt to call their methods "organic," because that's a label universities that might be best positioned to help new growers develop sustainable techniques are barred from doing, lest they lose federal funding. Even to grant interviews on the subject is tricky. Oregon State University's public relations department declined an request from Newsweek to speak with a pesticide expert at the school, citing a policy that "prohibits faculty from conducting research that involves the possession, use, or distribution of marijuana unless such research is in compliance with already established guidelines set forth by federal agencies."

Washington State University entomology and environmental toxicology professor Allan Felsot is similarly bound, though he chooses to ignore the admonition from the "suits."

"Growers are really flummoxed about how to control these pests," Felsot told Newsweek. "If you're spraying a miticide and you don't need to, you're wasting money, but if you're doing a practice that's exacerbating your mite population, you're also wasting your money."

The absence of federal oversight has left states to their own devices to figure out how to address pesticide use in cannabis farming. California growers rely on a program called "Clean Green Certify" that mirrors the U.S. Department of Agriculture's organic program and requires inspections and pesticide tests. Of the 23 states that have passed laws allowing medical marijuana, 17 of them and the District of Columbia have adopted rules governing pesticide use in pot growing. Six states have no such rules. Five explicitly ban pesticide use.

Felsot isn't particularly concerned about the amount of pesticides or the dangers of those pesticides in the pot grown today. It's easy enough to find trace elements of bad stuff in pot if you look hard enough for it, but partly because of the research deficit there's no way to know how much pesticide is harmful to a user and how much that user's consumption might affect their risk. "With more exposure data, we could do a better job of estimating the risk," Felsot said. Meanwhile, "I think the risk of any health effects from pesticide residues is low. I'm a user. If I were concerned, I would really watch it."

Consumers are increasingly focused on finding sustainably grown pot, says Cambria Benson, director of marketing at a Portland dispensary called Serra.

"Seventy-five percent of the customers coming through the door now are asking about organic," she told Newsweek. "Everyone in Portland wants to know where their lettuce and meat comes from. We have to have the same approach with our flowers."