With the passage of the Marijuana Regulation & Taxation Act (MRTA) and resultant legalization of recreational marijuana in New York State, a significant debate has arisen among farmers and investors over the superiority of outdoor cannabis cultivation. The questions in discussion are: “why choose sun-grown cannabis?” And, “what makes outdoor cultivation superior to indoor cultivation?” Considerations for answering these questions are numerous, and apply to growing both THC cannabis (marijuana) as well as CBD cannabis (hemp).
Traditionally, cultivated cannabis has been grown in indoor environments primarily for reasons of illegality and security. As we enter the post-prohibition era of cannabis in New York State, these reasons are no longer sufficient to justify recreating an artificial growing environment for cannabis. Indoor cannabis cultivation is very systems-intensive, extremely expensive to build, maintain and monitor, and creates an enormous carbon emissions footprint every step of the way. According to the Lawrence Berkeley National Laboratory, indoor grown cannabis is the most energy intensive crop in the U.S.
Indoor grow environments are 50-200 times more energy intensive than an average office building. That means they require a lot of energy, and have a high overhead with building/renting costs, utilities, garbage removal, high intensity lights, air conditioning, fans, heaters, dehumidifiers, water purifiers, security equipment, building renovations, capital investment in equipment, water and electric bills, CO2 gas application, imported soilless media replacement, back-up generators, and more.
Indoor grow facilities are also costly for the environment. New research from March, 2021 shows that U.S. indoor cannabis cultivation results in life-cycle greenhouse gas (GHG) emissions of between 2,283 and 5,184 kilograms of carbon dioxide per kilogram of dried flower. To compare, emissions from electricity use in outdoor, greenhouse, and indoor cannabis growth, releases 22.7, 326.6 and 2283 kilograms of carbon dioxide, respectively.
Life-cycle Greenhouse Gas (GHG) Emissions for Cannabis Cultivation, per dried flower
Artificial/Indoor Greenhouse Outdoor
2,283 - 5,184 Kg 326.6 Kg 22.7 - 326.6 Kg
carbon dioxide carbon dioxide carbon dioxide
This scale of energy consumption and resulting emissions will nullify the 2019 New York Climate Leadership and Community Protection Act’s (S6599) set target of 85% GHG emissions reduction by 2050.
When natural environmental conditions are artificially recreated indoors, growing media is one element that must be imported. Imported soilless growing media is typically nonliving, lacking in soil microorganisms (offering a significantly diminished rhizosphere necessary for healthy plant growth) and has lower fertility needing to be frequently amended. Often imported media is replaced and discarded when new crops are grown. Growing media that is void of a healthy microbial composition also requires the application of synthetic fertilizers and other amendments, which are often made from petrochemicals. Those that are not absorbed by the plants are subsequently released in waste water into the environment.
Further, cannabis plants grown indoors are grown as a monoculture crop. This lack of biodiversity increases the potential for pathogen and pest problems, which invariably leads to increased use of pesticides and fungicides to control the outbreak of pests and diseases.
Under these artificial conditions indoor cannabis crops become a standardized commodity rather than the health-promoting plants they naturally are and should be allowed to be—plants with qualities that benefit living organisms as well as the environment.
Enter outdoor grown cannabis. An outdoor growing environment is the most natural and energy efficient for cannabis, and allows plants to grow to their fullest genetic potential with full natural cannabinoid and terpene profiles. The elements required for plant growth – free energy from the sun, fresh air, carbon dioxide and rainwater – are provided by the natural environment, significantly reducing expenses and a carbon emissions footprint as compared to indoor growing environments. Natural outdoor soil, such as the fertile soil of the Hudson River Valley, is rich in native microbes providing for the natural symbiosis of living and non-living soil components conducive to maximum plant growth and health. Alive soils are efficient at nutrient uptake maximizing the use of applied natural, organic fertilizers. Plants are also accessible to natural predators and beneficial insects to help control potential pests.
Cannabis grown outdoors positively contributes to ecosystem dynamics and the regeneration of healthy ecosystems. When grown within the proximity of other crops, forest and fields, as it often is, it promotes biodiversity. Outdoor plants capitalize on fresh air and wind for natural ventilation. Larger volumes of plants can be efficiently grown outdoors in one or two crops, rather than in multiple crops in indoor facilities.
To consider the bigger picture, as society continues to implement methods and practices to address the climate crisis, there needs to be a basic dual focus: (1) to reduce the introduction of new carbon emissions to the atmosphere; and (2) to drawdown and sequester carbon already present in the atmosphere. Growing cannabis outdoors addresses both. The carbon footprint of an outdoor cannabis growing practice is absent, negligible or even carbon negative. Cannabis, the highest carbon dioxide to biomass conversion crop, sequesters large volumes of carbon from the atmosphere and stores it in the soil, improving soil biota and conditions, and making it readily available as a plant nutrient. Overall, outdoor growing is most conducive to increased plant and ecosystems health.
The recent passage in the New York State Legislature of The Soil Health and Climate Resiliency Act (A5386A), “establishes the climate resilient farming initiative to promote and encourage farmers to reduce the effects of farming on climate change and to adapt to and mitigate the impact of climate change by improving and maintaining water management systems and soil health and resiliency.” Outdoor grown cannabis will significantly contribute to achieving these goals.
And finally, since cannabis is a bioaccumulator, when it is grown outdoors it absorbs the flavors of the earth, mineral content, climate, locale, the impacts of wind and rain, and sun exposure, resulting in a plant made up of unique regional characteristics, a true product and expression of its environment, and creating a distinct “terroir.” The Hudson Valley of New York, has one of the most ideal regional climates to grow high quality cannabis and therefore, is an essential factor in the success of the state’s cannabis industry. The Hudson Valley has clear and eminent potential for producing high-quality organically grown cannabis. And this distinction is only possible when cannabis is grown outdoors by experienced growers.
As more consumers demand to know the source and quality of their cannabis and the sustainable practices with which it is grown, it is clear that outdoor grown cannabis is the preferred, obvious and justifiable choice.
Diane Duffus
Biologist and Educator
Hepworth Ag Inc
June 12, 2021