Food & Farming

With Legalization, Will Outdoor Cannabis Farms Pop Up Around Rhode Island? Maybe.


Although Rhode Islanders cultivating cannabis for themselves can already grow the plants outdoors, under the current medical marijuana regulations, licensed commercial cultivators must grow pot indoors. (istock)

As Rhode Island regulators begin to put into practice the state’s new recreational marijuana law, they’ll have plenty of logistics to figure out, including whether to let licensed cultivators grow their crops outside.

While indoor cannabis facilities will likely remain a large part of the industry in the Ocean State because of Rhode Island’s climate and federal regulations, outdoor cultivation could be a more energy efficient (and less expensive) alternative to current practices.

Although Rhode Islanders cultivating cannabis for themselves can already grow the plants outdoors, right next to their hydrangeas, under the current medical marijuana regulations,  licensed commercial cultivators must grow pot indoors, for both security and overproduction reasons.

The prohibition on outdoor commercial growth will remain in place until the state Cannabis Control Commission creates full adult-use regulations, according to Matthew Santacroce, chief of the state’s Office of Cannabis Regulation.

The commission could allow outdoor growing as it parses specific regulations, a process which will take place before applications come in, probably sometime next year, Santacroce said.

Allowing cannabis to be grown outdoors could dramatically reduce the amount of energy used for marijuana production. According to a 2021 study, switching from indoor to outdoor growing could lower a cultivator’s emissions by at least 80%. And that estimate is conservative, according to one of the study’s authors, Colorado State University associate professor Jason Quinn.

The study found that artificial light and climate control systems in indoor growing facilities, along with the common practice of pumping extra carbon dioxide into the plants’ growing environment to increase photosynthesis, all increase indoor growers’ carbon footprints.

“Plants are not very efficient at the conversion of solar energy into biomass, but we don’t typically care about that, because the sun is free, right? So that inefficiency doesn’t really matter,” Quinn said. But when the cannabis plants at an indoor cultivation facility depend on tons of man-made light because of that inefficiency, it increases a facility’s carbon emissions and electricity bill.

The indoor growing process also necessitates heating, ventilation, and air conditioning systems to maintain proper growing conditions. The facilities that the study looked at were doing a high number of air exchanges, pumping air in and out of a facility “upwards of 60 times per hour,” Quinn said.

A typical HVAC system does 30 air exchanges an hour, he said, but the indoor cannabis growers’ systems were operating like a hospital’s.

That takes a lot of energy and increases carbon emissions, he said, even more in a place like Rhode Island, where temperatures swing from very high to very low. 

Although the hemp plant looks and smells like cannabis, it can be legally grown outside, unlike marijuana. (Colleen Cronin/ecoRI News)

On top of these two factors, many cultivators also artificially increase the concentration of carbon dioxide in the growing environment because it encourages more frequent photosynthesis in the plants and then more growth. 

Quinn said the added CO2 does not contribute to the facility’s carbon footprint, it counts toward the original waste source, which is usually an ethanol facility. Instead, the energy that is used to capture, transport, and apply the carbon dioxide to the growing environment counts toward the marijuana grower’s carbon emissions. 

These environmental costs also translate to financial burdens. Mike Simpson, one of the owners Lovewell Farms, an organic hemp farm and CBD producer in Hopkinton, said that even though he and his business partners would like to enter the THC business, the cost of moving growing inside would be too burdensome.

The price of creating and keeping an indoor facility prevents smaller producers from entering the market, he said.

Despite the environmental and fiscal costs of indoor growing, it is likely that pot grown indoors will still need to supplement bud cultivated outside, even if outdoor growing is legalized, according to Jared Moffat, who worked on the campaign to make weed legal in Rhode Island and is the state campaigns manager for the Marijuana Policy Project.

Rhode Island’s extreme weather would restrict when cultivators can grow and harvest their crop outside, and because marijuana is still illegal federally and can’t be transported across state lines, all of Rhode Island’s cannabis must be grown locally, he said.

Growing the plants outdoors can also be harder to manage, both from a security and quality control standpoint. 

Cannabis has been stolen from outdoor facilities, but there are examples of outdoor growing in other states, including Massachusetts, where greenhouses and outdoor facilities are required to have “sufficient security measures” and “perimeter security fencing designed to prevent unauthorized entry.”

The quality of outdoor cannabis flower is also a hotly debated. Cannabis grown outdoors in the United States often ends up in oils rather than used as smokable products, Moffat said. 

Moffat said a solution might be a hybrid form of growing or the utilization of greenhouses to reduce emissions while also maintaining supply, ensuring quality, and keeping local producers that have already been growing for the medical industry in business.

State Rep. Scott A. Slater, a Democrat who represents District 10 in Providence who sponsored Rhode Island’s new recreational marijuana law, said that at least initially, he thinks only indoor growing will be allowed because of security issues and concerns about overproduction.  

Slater said during the legislative process, most of the push for outdoor growing he heard was coming from large growers who plant hemp, which is legally allowed to be grown outside.

“I guess the hemp market’s kind of dried up and there’s so many people doing hemp that they find themselves with this business plan that they had,” he said, and with expensive equipment on their hands for a product that didn’t take off as expected that could also be used for marijuana plants.

“Now, they want to jump into the THC market,” Slater said. “With the size of their grow, they probably would have wiped out a lot of what the cultivators have been working on.”

Despite those concerns, Slater said that he thinks the issue should be revisited if towns support it, demand is there, and sustainability is at the forefront of the push. Issues like this are why the Cannabis Control Commission was established, he added.

“It’s an important issue, sustainability,” he said, “and I would be open to looking at it.”

Colleen Cronin is a Report for America corps member who writes about environmental issues in rural Rhode Island for ecoRI News.


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  1. If you want to get a first hand look at the environmental impact of outdoor V indoor I’d be delighted to share some real data. We grow on 20+ acres in a different state. I am a RI resident, lived here a long time. This is an incredible opportunity for the ag community.
    We harvest 15-20k pounds annually.

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