Marijuana is said to be the most energy-intensive agricultural crop in the United States, consuming one percent of the entire nation’s energy output. It drains resources because of its high energy and water requirements. When pesticides are used, and that’s often, its carbon footprint gets even more troubling. Cannabis may grow green, but growing it is far from green in the sustainability sense.

And Maine, already home to a flourishing legal medical marijuana industry, is about to see a surge in even more growers as legal recreational usage for those 21 and up, approved by voters in November, goes into practice. That law allows for commercial marijuana cultivation up to 800,000 square feet, and ultimately, perhaps more if the state licensing agency determines more is needed to produce enough supply for the demand.

Legal marijuana is big business and getting bigger each year. Last year, sales went up 30 percent in North America to $6.7 billion, according to the ArcView Market Research Group, which tracks trends in the cannabis industry. There’s no telling when the complications of regulation for recreational sales in Maine will be worked out – a bill proposed in the legislature last week would delay the rollout of retail shops until February 2018 – but residents over 21 years old will likely be able to grow six plants for their own use starting in a matter of weeks.

Warehouses, greenhouses or gardens bursting with energy-sucking marijuana are an anomaly in a state that prides itself on its efforts toward sustainable growing practices in everything from beef to barley production.

Signs indicate that the industry’s approach may be changing, however, on both a national and state level. “The big conversation being had within the industry right now is about sustainability,” said Hunter Holliman, director of process development for 4Front Ventures, an investment and consulting firm in the medical cannabis industry. “I think people are starting to realize that the days of the 60,000- to 100,000-square-foot warehouse, with tons of high pressure, high-voltage lighting, are going to go by the wayside.”

Moving away from those “dinosaurs,” he said, is primarily motivated by profits. “The price point ends up being so high because of all the electricity that goes into the lighting and cooling.”

In Maine, medical growers say they are making efforts to improve notoriously inefficient growing methods. For instance, many of the lights used to push the plants’ growth also create so much heat that even in a Maine winter, a pot farmer will have to provide some means of cooling the air or risk over-heating the crop. In Unity, medical marijuana caregiver Dawson Julia uses only maybe a third of his 14,000-square-foot warehouse, an old creamery that dates back to at least 1910. The building, which he says once housed a potato canning factory and a printing press as well, came with three furnaces, but Julia uses mini-splits, the high-efficiency heat pumps Mainers have been installing in droves and funnels the heat from the lamps into a duct system to distribute it and keep about 5,000 square feet of the building warm.

Julia, at his company, East Coast CBDs, has also ditched all chemical fertilizers in favor of organic, is looking into putting solar panels on his roof and is part of a MOFGA trial for a clean cannabis growing certification program that would encourage cultivation more in line with organic practices.

Meanwhile, Maine’s biggest medical marijuana grower, Wellness Connection, is buying energy credits, reusing water and investigating using more efficient grow lights.

Wellness Connection operates four dispensaries (in Bath, Brewer, Gardiner and Portland) and one growing facility in Central Maine. They’ve gone paperless with their patient interactions and increased recycling – collecting 3,500 pounds of plastics and diverting them from landfills in 2016. And they’ve attempted to mitigate the stress their crops put on the environment by offering clients a discount if they bring packets of native seeds to the dispensary, which Wellness in turn donates to groups like Portland Trails to plant.

That might seem like a minor thing but Patricia Rosi, the chief executive officer of Maine’s biggest medical marijuana dispensary, Wellness Connection of Maine, says it adds up.

“We’ve collected about 1,000 of these seed packets,” Rosi said.

Sustainability is a priority for Wellness, she said, particularly in light of the cannabis industry’s rapid growth.

“As we are becoming a recreational-use state, I think it is more important than ever to make sure that the production process is careful of the environment,” she said.

At East Coast CBDs in Unity, Billie Pirruccello adds water to soil she just mixed. East Coast CBDs also uses high-efficiency heat pumps and forgoes chemical fertilizers in an effort to boost sustainability.

TURN OFF THE LIGHTS?

The biggest single environmental problem with marijuana cultivation is how much power it requires, specifically electricity. No matter what strain of marijuana is being grown, in Maine it’s grown almost entirely inside, for security reasons required by law and also by nature’s law. It’s not that marijuana can’t be grown outdoors in Maine, but its season would be limited to the summer. (Also, growing outdoors could lead to a pest problem, which in turn could lead to environmental problems. In 2014 scientists traced the death of animals like the Pacific fisher and endangered spotted owls to rat poisons used in outdoor marijuana farms in Northern California.) Growing inside means being able to control the plant’s development while adhering to security rules written into the medical marijuana legislation.

But indoor growing means that grow lights are an absolute necessity and the more popular ones to use, the ones that can push a flowering plant into optimum conditions for a good yield, burn a lot of electricity. Consider the case of the Monroe woman convicted in 2014 of running an illegal pot farm with her family; one piece of evidence linking her to the farm was $25,000 in electric bills she paid to Central Maine Power in a two-year period, for what was listed as a residential property. (And you thought you were spending too much lighting the house up for the holidays.)

Alternatives exist, like light-emitting diode or LED lights, which are just starting to be used successfully in some places. In Washington state, a utility called Puget Sound Energy has given out grants to growers for these expensive, sophisticated lights. But Rosi said that Wellness Connection has yet to find LED lights that will suffice for their operation. A frequent complaint about LED lights among growers is that the plants’ potency is negatively impacted by being grown under LED.

“We are using a mix of HPS (high pressure sodium), some T5 fluorescents,” she said, explaining that the plant’s lighting needs vary during the different stages of growth.

“There is a lot of LED on the market that is getting better,” Rosi added. “If I had a crystal ball, I would say that probably in four years we will all switch to LED. As of now, it is getting there but it is not as good as the other ones.”

Rosi hopes that the arrival of a retail market for marijuana in Maine – and in other states, like Rhode Island and Massachusetts, which also voted for recreational legalization in November – will open the door for improved efficiencies through incentives. “One thing that would fast track the implementation of LED for all of us would be if there were tax credits linked to switching to it.”

Dawson Julia looks over soil cooking in a room at East Coast CBDs. Julia also uses reclaimed water on his plants. He is one of five growers in MOFGA’s trial for a proposed clean cannabis program.

EFFICIENCY MARYJANE

Tax credits would have to come from the state. Marijuana remains illegal on a federal level; it’s a Schedule 1 drug in the U.S. government’s eyes, considered in the same category as heroin. Because of that, growers are ineligible for many grants designed to help farmers become more sustainable.

But there are work-arounds. In Maine, a grower could make the switch to LED and receive rebates from Efficiency Maine. Michael Stoddard, executive director of the independent administrator for energy efficiency programs in Maine, said Efficiency Maine doesn’t require residential applicants to explain what they’re doing with any of their new high-efficiency LED lights or heating and cooling systems. Dawson Julia, for instance, says he got $500 rebates for his heat pumps, but his operation is small-scale, encompassing plants grown by three state licensed caregivers including himself.

However, on larger projects such as would be seen at a licensed commercial grower, Efficiency Maine might ask questions about, say, forecasted hours of use for lights. Efficiency Maine staff has been out to one medical marijuana growing operation to learn about its energy use. Two commercial growers have submitted applications to Efficiency Maine, but Stoddard said they opted not to go through with their proposals.

With the retail component of the recreational law likely up and running within a year, new licensed commercial operations, remember, up to 800,000 square feet, throughout the state could impact Maine’s power grid. But Stoddard said steps could be taken to mitigate that.

“We are hoping that as people develop these projects that they will talk to contractors or they will talk to us to see if there are high-efficiency options,” Stoddard said. “The energy bills are going to add up over time. We hope that they are thinking up front about what the efficiencies are going to be.”

In Colorado, which has been at the forefront of efforts to legalize marijuana, energy usage has already spiked since recreational use became legal. The Denver Post reported in 2015 that Denver’s electricity usage is rising at a rate of over 1 percent a year, nearly half of which comes from marijuana-growing operations. The increase coincides with nationwide efforts to drive electricity usage down, diminishing societal reliance on fossil fuel-fed electricity, such as that produced by coal-fired plants.

Denver’s goal has been to cut 80 percent of its emissions by 2050. More growers hooking onto the grid aren’t going to help the city reach that.

Evan Mills, a researcher from the Lawrence Berkeley National Laboratory in California, published a study in 2012 that claimed that indoor operations in California alone, both illegal and legal, used so much electricity that the additional greenhouse gas emissions were the equivalent of putting 1 million more cars on the Golden State’s roads. That study estimated that it takes 13,000 kilowatts annually to produce about five pounds of marijuana. That’s more electricity than the average American household uses in a year. And when you’re talking about $6.7 billion in sales, it becomes clearer why marijuana is the most energy-intensive crop in the United States.

THE MONEY AND THE ENGINEER

But just as vegetable farmers want to make that perfect head of lettuce they’re cultivating cost less to grow without sacrificing quality, so do pot farmers. As the industry has matured, they’ve gotten more interested in efficiencies.

“People have had the time to reflect and think about, ‘What can I do better?’ ” Holliman said.

It might be said that inside every marijuana grower beats the heart of an engineer. “You are always trying to look for the next trick,” said Dawson Julia. “The faster you can figure that stuff out, the faster you can grow your business.”

Julia started growing in a garage, and that’s where he first rigged up a rain barrel system to collect the water thrown off by his heating and cooling system so he can water the plants with it. When he moved to the Unity warehouse in 2014, he brought that “technology” with him.

One of the oft-cited statistics about marijuana cultivation’s unsustainability is that every plant requires about six gallons of water a day to thrive. That’s a damning number. But Rosi said Wellness Connection uses more like a half-gallon per plant per day and Dawson says his plants get about a gallon, all of it reclaimed (and tested regularly to make sure it’s not contaminated and that the pH levels are right).

“We never turn on the faucet,” Julia said.

He’s still working on getting his electricity costs – about $4,000 a month – down. But as one of the five growers in MOFGA’s trial for a proposed clean cannabis program, he found an unexpected efficiency in going with organic tools to grow his plants. Because marijuana is still illegal on a federal level, it can’t be deemed “organic” even if all the growing practices adhere to organic methods. When Julia made the switch to from a chemical fertilizer to a certified organic fertilizer, he was pleasantly surprised. He and his fellow caregivers in Unity used to spend about $1,000 every few weeks on fertilizer that came in five-gallon jugs. Now they buy a fertilizer composed of ingredients like sea kelp, fish bone meal and bat guano – and it’s far cheaper.

“You end up saving a crap ton of money,” he said. “We have saved at least 90 percent on our fertilizer costs.”

Katy Green, MOFGA’s organic transitions coordinator, said the five members in the trial demonstrated they’ve met the standards MOFGA developed and were issued “clean cannabis” certificates last fall. “The standards that we have developed largely parallel the organic standards,” she wrote in an email. “We require soil-based production, and growers are using natural sources of soil fertility for their crops.” Green said MOFGA gets calls weekly from caregivers around Maine (there are nearly 3,000 of those) asking about the clean cannabis certification. But it’s up to the MOFGA board to decide whether it will launch a full program.

Rosi said a grower such as Wellness wouldn’t be eligible because it grows hydroponically. But Wellness Connection uses an Integrated Pest Management program that takes a multi-faceted approach to preventing and mitigating the threats posed by pests and diseases. “To date, one of the most successful pieces has been our biological control program,” she said. They bring in beneficial bugs, “insect species that target specific pests that exist in the crop or could exist in the crop.”

It’s all part of a process, Rosi said. She recognizes that Wellness, and Maine’s other growers, have got a long way to go when it comes to sustainability. “There is no silver bullet,” she said. “It takes a lot of commitment and an implemented approach.”

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