The legal cannabis movement is quickly sweeping across America. The market is poised for a pivotal 2018, with more than a dozen states considering legalization. Support for legalization is also higher than ever with more than 60 percent of Americans in favor, according to a 2017 CBS News poll.


A report from New Frontier Data—a data analysis company devoted exclusively to cannabis research—shows the pot industry will create more than 280,000 jobs by 2020. While economic benefits seem to appease the long-standing debate over marijuana legalization, Americans must consider the enormous negative environmental impacts the plant could have.


Indoor growth demands

Legal indoor cannabis growing facilities have a massive energy bill year over year. A 2012 study from Evan Mills, a senior scientist at the Lawrence Berkeley National Laboratory found that growth facilities accounted for about 1 percent of national electricity use at $6 billion a year. In comparison, the pharmaceutical industry uses $1 billion in energy costs annually.


High energy bills at indoor grow facilities—where other environmental factors can be better controlled—are impacted primarily by the unique lights used to grow cannabis. The indoor lighting consists of high-pressure sodium (HPS) lights that are extremely energy inefficient. The strain on electric grids and the cost to maintain the plants can be astronomical, and while the plant is legal in many states, the government still mandates that cannabis plants be kept out of the public eye, promoting the use of the HPS lighting systems and indoor growing facilities.


Another energy barrier growers face is cannabis’s federally illegal status, restricting rebates for growth supplies. While using LED lights for growth would be more environmentally friendly, they are substantially more expensive. If farmers aren’t guaranteed a return on investment, there is no incentive to “go green.”


Outdoor water demands

Aside from the plant’s electricity demands, marijuana is a water-intensive crop. A recent Humboldt County report revealed that in the northern coastal region of California, it’s estimated that more than 22 liters of water are used per plant per day during the June to October outdoor growing season. The average outdoor marijuana planting density is about 130,000 plants per square kilometer, therefore using about 430 million liters of water per square kilometer for a typical growing season.


According to a 2015 report focusing on the environmental factors of cannabis legalization, The plant is estimated to be almost two times more “thirsty” than wine grapes. The below graphic also illustrates the irrigation requirements for other crops in the California area. While weed is not the highest on the spectrum, it still requires an abundance of water in an extremely drought-stricken area.



Much of the water used to grow cannabis plants come from wetlands and streams that are already struggling with drought. While the environmental footprint of pot plants grown indoors and outdoors can pose a significant environmental threat through greenhouse gas emissions and pesticide application, many argue that legalizing the plant could bring less environmental harm than current farming practices.


A recent report on cannabis cultivation opportunities suggests that if legal cannabis production gains national acceptance, the desire to develop environmentally sound production practices will grow, and policies adopted in early-adopter states like Washington and Colorado may shape practices in the new industry nationwide.


A path to sustainable growth


For crop farmers, unruly irrigation tactics can be an immense source of wasted water. By implementing a water technology system that monitors and measures irrigation flow onsite, cannabis growers can reap the benefits of smart water savings and minimize the plant’s impact on a dwindling critical resource.