Leaving footprints: Can growing indoor cannabis be sustainable?


THC Design in downtown Los Angeles is one of California's most sustainable indoor cannabis cultivation facilities. Photo courtesy of THC Design.

Growing commercial cannabis outdoors requires a few specific things: open land, ample water, and a fertile terroir. Southern California lacks most of these features, which is a big reason why the cities and counties in the region that have approved cannabis cultivation require it to be done indoors. That’s made SoCal the epicenter for legal indoor cannabis cultivation in California. 

Growing, selling, manufacturing, and distributing cannabis is legal in the city of LA, but it’s not yet in LA County. That’s about to change, though. Last year, the LA County Board of Supervisors approved a motion to open up unincorporated LA County to legal cannabis businesses. 

The county is still figuring out how to make that work. As part of that effort, the board tasked the head of the county’s Office of Cannabis Management, Hyunhye Seo, to investigate the environmental impacts of the legal weed industry. She and her team determined that outdoor cultivation was too water-intensive and that it would be harmful to the surrounding community. As such, Seo says the new LA County regulations will only allow for indoor and solid-structure greenhouse cultivation. 

As of now, all outdoor grows in Southern California are illegal operations. Seo says they’ve caused a lot of problems.. 

“Water theft, trespassing, pesticide and waste runoff, and increased criminal activity. … We're just trying to move in good faith with these communities who are very upset, understandably so; build better trust with both the industry and the community members; and just really show progress and steps that we're taking towards promoting responsible businesses.”

But indoor cultivation has one major problem –  it’s not environmentally friendly for a couple of different reasons. 

Water is always one of the biggest concerns with cultivating cannabis. It takes twice as much water to grow cannabis as it does to grow commodity crops, like wine grapes. But water conservation is actually one of the ways indoor cannabis operations can shine — if water is recycled.

“For every 100 grams of water we put on a plant, we actually only use 33 additional grams of water from the well or from the city,” says Ryan Jenneman, the CEO and founder of THC Design. “So that is where we are able to provide the most efficiencies to the environment is through our recirculation of water.”

Besides recycling water in Downtown LA, Jenneman is in the process of building out a cultivation facility in the Coachella Valley. He says that facility will run fully on renewable energy and also reuse water the way many commercial agriculture facilities do. 

“Once water goes into the grow, it never leaves,” he says. “It's literally on an infinite loop. It shows you where commercial ag truly, truly is doing everything they can. Whether they care about the environment or not, which farmers do, farmers do, but it's because they can't waste anything.”

But water use isn’t the biggest problem with indoor cultivation — not even close. It’s carbon emissions. Researchers at Colorado State University estimate that the emissions associated with growing just an ounce of indoor flower is about the same as burning between seven to 16 gallons of gasoline. 

“When you look to California, or Southern California, we are talking about two tons of CO2 equivalent per kilogram of dried flower,” says Jason Quinn, one of CSU researchers. “I mean literally tons of CO2 are being emitted.”

Los Angeles, Riverside, and San Bernardino Counties are home to well over 4 million square feet of legal indoor grows. Based on square footage data gathered from the Department of Cannabis Control, these counties alone produce at least 2 million pounds of cannabis per year, which adds up to billions of metric tons of greenhouse gasses.

“If you were to transition to an outdoor grow facility based on our first order calculations, you can have almost an instantaneous 80% reduction in those greenhouse gases,” says Quinn.

The good news? Even for indoor grows, there is a better way.

Out in Desert Hot Springs, the brand Gold Flora harvests hundreds of pounds of flower every week … and they use sophisticated, energy-efficient environmental controls. They’ve got a chilled water HVAC system. It required a big capital investment to install it inside their 35,000-square-foot facility.  But now that it’s up and running, facilities manager Adam Yudka says it’s really cost-effective.

“I mean, It's no different than getting a $10,000 rebate back to go into an electric car,” he says. “So the big thing is to just weigh it out and look at the cost payback and how long the payback's going to be back for our investors. … So there's got to be a reward in it. So it's all risk reward.”

It may pay off, but Gold Flora isn’t starting a trend. The only way cannabis businesses can afford the high cost of implementing energy-efficient systems is with the help of investors. And due to the industry downturn in California, most investors are not infusing capital into the cannabis industry right now. Most legal cannabis cultivators can’t shoulder the upfront cost.

There is one more way for growers to clean up their act: Create less waste. 

Most of the growing materials used in hydroponic growing facilities — such as rockwool and coconut husk — are thrown away after every harvest. Most medium-sized indoor grows harvest between four to six times a year. Massive indoor grows like Gold Flora can harvest every week. At Ball Family Farms, a boutique cultivator based in South Los Angeles, head of genetics Ashton Howarth emphasizes how much trash this is. 

“It just ends up as landfill waste,” he says. “Every single time you have a harvest, it goes right into the landfills.”

This is why Ball Family Farms switched from growing hydroponically in 2017 to growing in living soil, which lessened their waste considerably. And their dirt has been kept healthy with the help of writhing earthworms that have lived and reproduced in the soil for the past six years.

“Switching over to the soil system, we're able to actually treat and reuse the soil, so we've lessened our waste considerably,” Howarth says.

So what does all of this cost? The growers interviewed for this story gave me a range between $150,000 to $6 million, depending on the size of the facility. But they also unanimously agree that it’s worth the cost. Yudka, Gold Flora’s facilities manager, says the investment pays off in roughly three to five years' time.

“It's actually an economical gain for us. It turns out to be an environmentally-friendly practice, but it's actually a financially-beneficial practice for us as well.”

Indoor cannabis cultivation still has a ways to go before it’s actually eco-friendly, but at least in Southern California, these innovators are willing to give it a try.