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A marijuana grow room under LED lights in a warehouse at Denver Relief's grow facility in Colorado. Photograph: Bruce Kennedy/Guardian
A marijuana grow room under LED lights in a warehouse at Denver Relief's grow facility in Colorado. Photograph: Bruce Kennedy/Guardian

Greener marijuana: can a budding industry grow sustainable agriculture?

This article is more than 10 years old
As the cannabis industry comes out of the shadows, could legalization foster new transparency – and technology?

In a nondescript, unmarked warehouse in Denver's industrial outskirts, row upon row of marijuana plants – ranging from little cuttings to tree-like bushes – extend into virtual cannabis forests. A tropical atmosphere comes from carefully regulated humidity and lighting controls in each room, assisted by fans and vents.

This "grow" facility belongs to medical marijuana center Denver Relief, and it boasts something else besides healthy buds: state-of-the-art LED technology that offers the potential to dramatically cut energy consumption, not only for marijuana, but also for other large-scale commercial agriculture.

After decades of history as an outlawed business, complete with incidents of violence and destruction, the US marijuana industry is maturing. While possessing and selling marijuana is still a federal crime, medical marijuana is now legal in 20 states, plus Washington DC, which together make up more than one-third of the country. Beginning in January, the states of Washington and Colorado will also legalize the recreational use of cannabis for adults.

The growing societal acceptance has sparked what some call a "green rush" of people trying to cash in on what is already a multi-billion-dollar business. And as the marijuana industry comes out of the shadows, its producers, consumers and advocates are pushing for more transparency – both about cannabis' alleged medical benefits and its environmental impacts.

The industry has its work cut out when it comes to changing its reputation. Research from the University of California at Davis and Humboldt State University found that illegal growers – through bulldozing, use of fertilizers and pesticides, and more – have damaged forests, polluted watersheds and killed wildlife in Northern California.

Diversion of water for marijuana cultivation from the Eel River is endangering California's third largest watershed and one of the state's major salmon-producing waterways. "It's a race to the bottom in terms of environmental impacts," Scott Greacen, executive director of Friends of the Eel River, told the New York Times earlier this year.

Then there is the industry's massive carbon footprint. An independent study from a Lawrence Berkeley National Laboratory researcher in 2011 concluded that indoor cannabis production may account for 1% of US electricity consumption, equivalent to the power used by 2m average US homes. That comes to an energy bill of $6bn annually, with related CO2 production equal to 3m average cars.

Medical marijuana farmers say they want to adhere to environmental regulations and other laws to keep their products accessible and safe for their patients. "When you're dealing with people who are truly growing for medical reasons, the whole goal is to be compliant and follow by the rules," Alison Sterling Nichols, an environmental consultant for the Emerald Growers Association, a medical marijuana trade group, told Mother Jones magazine last year.

Will legalization make marijuana more sustainable?

And as the marijuana industry catches up with commercial agriculture, it's increasingly coming under control of professional growers who not only want to stay compliant with environmental regulations, but also want to find ways to cut their high land, water and energy costs.

Some indoor marijuana growers in Colorado are already using water catchment and tabling systems, as well as reclaiming and filtering greywater from their operations and nearing "zero wastewater" goals. But one area in which the industry may be ahead of other commercial greenhouse crops is lighting.

The LED technology at Denver Relief comes from the Florida-based Lighting Science Group, which has been conducting controlled tests almost exclusively in the medical marijuana industry. The tests have shown the lights can produce the optimal amount of the proper light spectrum that plants need for photosynthesis, says Neil Yorio, vice president of advanced projects at Lighting Science.

Yorio is a photobiologist who spent 20 years working at Nasa's Kennedy Space Center, where he studied how to grow plants in controlled environments for long-duration space missions. "The LED technology is ready," he said.

It's no secret that LEDs consume less energy than the high-intensity lamps that have traditionally dominated indoor marijuana growing. And their lower temperatures also result in a cascading series of energy-saving benefits – including less air conditioning, water and fertilizer use – that can cut overall electrical costs in half, Yorio claims.

But the medical marijuana tests are showing not only that the lighting can cut energy use, but also that it can keep crop yields high. "We've always been of the thought that LED technology is not where it needs to be to take over these high-intensity lamps like metal halide and high-pressure sodium," said Denver Relief co-owner Kayvan Khalatbari.

If the tests – currently confined to just part of the warehouse – continue to yield the expected results, Denver Relief plans to expand its LED usage to a large greenhouse under construction outside of Denver.

Will marijuana innovations move into mainstream commercial agriculture?

Cary Mitchell, a professor of horticulture at Purdue University, thinks the marijuana industry's work with LED technology might have practical applications in mainstream commercial agriculture.

He's the director of a $4.9m project to evaluate and improve LED lighting for America's so-called "specialty crop industry" – greenhouse-grown fruits, vegetables, nursery plants and other crops. Specialty crops bring in around $50bn annually, and their producers, like the commercial marijuana growers, are looking for ways to decrease energy costs while increasing greenhouse yields.

"They've undoubtably been doing this for years and years," Mitchell says about the cannabis growers' use of LEDs. "Since they don't publish their research, we don't really know how far they've taken the optimization. They probably are ahead of the specialty crop commercial production industry."

Medical marijuana producers, meanwhile, say they realize their industry has an environmental responsibility to its customers and communities, especially if it is to become further decriminalized.

As Khalatbari said: "The point is ... how can we make this practice more sustainable, because [this is] an industry that's really reached 5% of its potential, maybe, in this country, with so many states still to come online."

Bruce Kennedy is an award-winning journalist and communications professional who has covered international news, including business reportage, for MSN Money, CNN, NPR, Reuters Television and AOL's Daily Finance web site

More on this story

More on this story

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  • Legal cannabis market 'would be worth £1.25bn a year to government'

  • Why legalising cannabis isn't logical

  • New minister clarifies drugs stance after cannabis comments resurface

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