As Eric Christensen, a partner at Seattle law firm Gordon Thomas Honeywell, pointed out in his blog, the stereotype of cannabis growers is genial and environmentally conscious hippies, but in practice, illegal cannabis growers show little or no regard for the environmental impact of their operations.
Growing cannabis adversely affects the environment, with greenhouses having less impact than otherwise growing it indoors or growing it outdoors. When growing cannabis is illegal, growers will act as they please, but they can choose to go about things in a greener fashion. There has been scant peer-reviewed research into growing cannabis and the environment, so until more such research comes long, and that is so desirable, here’s a starter.
Cannabis is infamous for the amount of water it requires, with a large cannabis plant requiring as much as six gallons of water each day, twice as much as tomatoes or wine grapes. When the water is taken straight from nature, this dries up streams and rivers, which might trap fish. Usage can be reduced by watering more precisely. Water can also be reused. Don’t dump soil full of fertiliser into rivers and cause toxic algae, which has killed dogs. Don’t dam up waterways. Try to avoid creating access roads.
Use less chemicals
Chemical waste is one of the most pressing environmental concerns to plague the cannabis scene; illegal grows frequently employ fungicides, herbicides, pesticides and rodenticides that poison nearby wildlife and pollute water sources. It would be much better to use non-toxic chemicals and ideally go organic. Certainly, you don’t want to use chemicals intended for lawns or other things you don’t eat; because cannabis is inhaled rather than eaten, any toxins on it have a more direct avenue into the lungs and bloodstream.
Make it local
The environmental impact of cannabis growing can be minimised by keeping things as local as practicable, limiting long-distance transportation and the pollution that ensues.
Use renewable energy
The quantity of light it receives is the principal factor in determining the yield of a cannabis grow. The environmental impact of cannabis can be lessened by using renewable energy for lighting, dehumidifying and ventilation. Energy can account for a third of the production cost of cannabis growing. A report in 2012 that was covered by the Washington Post found that indoor cannabis cultivation, the worst kind, environmentally, might amount to one percent of the energy consumption of the United States.
Lighting is a massive element of growing cannabis indoors, consuming vast amounts of energy. So make it energy efficient. Reflecting light is one way to make savings here, and white latex paint reflects between 85 and 95 percent of the stuff. CO2 generators are used to boost plant productivity, representing a quarter of the carbon footprint of the process, and to avoid this, you could place your growing room next to a CO2-spewing gas appliance. Costs can be cut by getting CO2 from burning a candle and not using electricity.
Be smart with land
Instead of monocropping, outdoor cannabis growers should have growing patterns that are less disruptive, which is easier on the land.
One of the best ways to reduce the environmental cost of growing cannabis is to legalise it, so cultivation is no longer clandestine. Using sunlight instead of artificial light will have great benefits financially as well as environmentally, being free and not requiring ventilation systems. Apart from anything else, legalisation means you can tax it and not have to waste tons of money trying to stamp it out or put non-violent offenders into our overburdened prison system.