The Cannabis 411: Sustainability
How do we measure the impact of cannabis on the environment? This section will help you understand the key considerations and know whether your cannabis is produced in an environmentally-friendly fashion.
What is a carbon footprint?
A carbon footprint is defined as "the total set of greenhouse emissions caused by an [individual, event, organization, product] expressed as CO2e." It is the amount of carbon dioxide and other carbon compounds emitted due to the consumption of fossil fuels by a particular person, group, etc. The carbon footprint is the general term used for quantifying the environmental impacts of any operation.
What is sustainable?
“Sustainable” generally refers to the impacts of a practice not being detrimental to the point that it is draining on the inputs and environment around it to the point that it cannot support these activities into the future.A general opinion shared by many CA growers is that growing with sunlight is most sustainable. The Emerald Grower's Association lobbies for environmentally conscious growing; namely, by advocating for sun-grown weed. With California’s vast geographic expanse and varied climate, there are plenty of places to grow pot outside—but in the two states where recreational weed is legal, growers have been mostly forced indoors by weather and spatial considerations. However, the honest answer about the sustainability of cannabis is still not fully understood and will require future research to answer.
What is a carbon credit?
A carbon-credit is iterally-a permit that allows a country or organization to produce a certain amount of carbon emissions and that can be traded if the full allowance is not used. Some companies pay for credits that other companies have earned and sold to offset the carbon footprint their practices produce. By purchasing the ‘credits’ of companies that are less impactful other companies with more of an impact can purchase these credits to have a lesser ‘perceived’ carbon footprint.
What is regenerative?
Regenerative practices actually rebuild the state of the environment in which they are being practiced. There are many different approaches to regenerative agriculture that are included in this including Permaculture, Bio-dynamic, hugel kulture, no-till soil, compost/worm/weed teas, addition of ‘bio-accumulators’.
Cannabis is a regenerative plant. This means that due to seasonal variations in daylight, wild plants germinate, grow, flower and die within the course of one year. Then in the following year, new plants will grow from seeds produced by the previous generation. However, it is also possible to rejuvenate a plant after flowering, and ‘trick’ it into producing again. 
When harvesting a mature cannabis plant, the larger terminal flowers in the lowermost 1/3 portion of the plant should be removed, but smaller buds and leaves shouldn't be touched. These smaller buds are critical in starting the regeneration process; thus, it is wise to leave as many small buds on the lower branches as possible. Once the process of regeneration begins, new growth occurs more rapidly at the lower branches.
The importance of having an organized internal structure of a farm is as important as the rest of the aspects of sustainable approaches. Through thoughtful creation of company Standard Operating Procedures (SOP) and Quality Management Systems (QMS) emergencies can be planned for and the overall systems of the grow can be looked at and studied for efficiency of all operations. Treatment and training of employees comes into play here to see if these methodologies are sustainable for growth of company staff and adherence to employment laws are being maintained.
Farm procedures include cultivation methodologies like whether a farmer is growing indoors, in a greenhouse or field grown. Whether the plants are being grown in soil, soilless, hydroponic or in ground. How the plants are fed or watered via hand or drip irrigation, etc. Harvest procedures can be studied to determine sustainable approaches to harvesting, curing, packaging and shipping.
Energy use has the potential to be the least sustainable aspect of Cannabis cultivation. This is the topic that is most talked about on a National level due to the large footprint of indoor cultivation’s electric draw for lighting and cooling. It is said that about 9% of California energy and almost 1.5% of the national energy use goes to indoor Cannabis cultivation. Greenhouse cultivation can reduce energy costs by about 75–80% and field grown can reduce it even more. As people are becoming more educated as to the benefits of full spectrum Sun grown Cannabis and the heavy impacts of indoor cultivation the trend is moving more towards full sun and light dep greenhouse grown.
Water and Cannabis
Especially important in California is the water consumption needs of growing Cannabis. Sustainable water practices can include drip irrigation and timing of watering as well as whether or not people use Reverse Osmosis (RO) water filtration equipment in their watering systems. RO systems can be as inefficient as using ten gallons to produce one gallon of filtered water. Watering in the middle of the day allows for an increase in evaporation. Drip irrigation allows watering to be monitored so that the exact amount of water is given to a plant whereas as watering with a hose or a bucket makes the amount of water being used less consistent and more difficult to monitor. Mediums that the plant are being grown in will also affect the amount of water being used for the plant. Closed loop hydroponic systems are the most water efficient though most hydro designs have other potential issues due to the use of non organic nutrients in the system. Some soil and soilless mediums are meant to be very porous and don’t retain water very well making it necessary to use more water more often. Constant watering is sometimes a desirable aspect as some growers like to get a nutrient dense liquid to their plants as often as possible. Water absorbing additives and ingredients can be used in soil and soilless mixes to make them more water retentive.
What are environmental impacts of growing indoors?
The environmental impacts of growing indoors often concern the use of a lot of electricity. "Diesel dope," the kind nurtured inside factory-sized warehouses under horticultural lamp light, is unbelievably carbon-intensive, and the current annual CO2 emissions volume of all such facilities nationwide is "equal [to] that of 3 million cars," according to a study conducted by Evan Mills of Lawrence Berkley National Laboratory. The analysis also highlights that "a single [lamp grown] cannabis cigarette... is equal to running a 100-watt light bulb for 25 hours of average US electricity."
Scientific Paper: The Carbon Footprint of Indoor Cannabis Production
What are the environmental impacts of growing outdoors?
Some of the main concerns about the environmental impacts of growing cannabis outdoors is the use of water from rivers and streams which could threaten wildlife species who rely on those sources. Cannabis plants require nearly twice as much water as do grapes or tomatoes, and the last five years have brought a 50 to 100 percent increase in the amount of northern California watershed lands used for marijuana production – figures that are causing growing concern among conservationists in the midst of a severe statewide drought.
The majority of California agriculture is subject to heavy water use regulations. Farmers of most irrigated crops help their plants through the dry summer months by filling water tanks in the winter, when streams and springs are full. By contrast, many marijuana growers draw surface water during the plant’s summer growing season, when drought conditions are worst.“Taking water directly from rivers and streams in the summer not only reduces the water available for agriculture but also threatens wildlife species, especially birds and fish, that depend on these wetland ecosystems for survival,” said Naylor. Illegal marijuana plantations in California are associated with a wide range of other environmental impacts, including pollution, poaching, and pesticides that poison wildlife. Even legal outdoor cultivation can cause deforestation and soil erosion.