Weed has a long horticultural history in various human societies. However, it’s only recently that nations like Canada and the USA have grown this plant for masses of consumers. As laws surrounding cannabis lighten up, more facilities are pumping out pot to meet increased demand. Unfortunately, the rapid growth in the cannabis cultivation sector is putting a strain on the environment.
Cannabis Sustainability: Major Challenges & Proposed Solutions
Weed activists can’t ignore the high energy demands of indoor cannabis cultivation. Data also suggests cannabis waste and CO2 production can harm air quality. Thankfully, as more people learn about the challenges of sustainable cannabis cultivation, researchers and businesses are developing ways to scale their operations responsibly.
The Energy Costs Of Cannabis Cultivation
Currently, cannabis experts’ primary concern regarding weed’s sustainability is its energy consumption. Multiple reports suggest cannabis already accounts for 1% of the total energy use in the USA. In weed-friendly states like California, that energy rate is closer to 3%. Plus, after cannabis legalization in Colorado, Denver posted a 45% jump in total electricity demand.
According to research from Colorado’s Cannabis Sustainability Work Group (CSWG), roughly 51% of total electricity use in the indoor cannabis cultivation sector is related to HVAC machines and dehumidifiers. Lighting accounted for 38% of energy consumption, and space heating was in a distant third at 5%.
Clearly, the prime targets for reducing energy use in the indoor cannabis sector are ventilation and lighting. There’s strong evidence that retrofitting to LED lights can almost instantly cut energy usage in cannabis grow facilities. In fact, scientists at Dartmouth College found that indoor cannabis rooms with LEDs had an average of 50% less energy expenditure versus HPS bulbs.
The CSWG also put forward a few suggestions for improving the efficiency of HVAC machines in cannabis cultivation facilities. A few of these proposals included:
- Increased usage of chilled-water systems and AC systems that have a hot gas reheat feature.
- Small grow operators should switch to mini-split systems.
- Double-check that dehumidifiers meet the Association of Home Appliance Manufacturers (AHAM) suggested rates of 80° F and 60% relative humidity.
Besides making indoor grow facilities more efficient, many cannabis advocates want to bring this plant “out in the open.” In other words, activists want to loosen the restrictions on cultivating cannabis outdoors. Increasing the percentage of outdoor-grown weed could significantly decrease the cannabis industry’s total energy consumption.
However, due to the federal ban on cannabis, it’s unlikely states will OK outdoor-grown weed. Not only is the legality on the front sketchy, some states don’t have favorable climates for growing outdoor weed year-round.
In response to these challenges, some sustainable cannabis growers have become more interested in greenhouses. Unlike warehouse facilities, greenhouses provide access to natural sunlight and weather controls. Encouraging more greenhouses could also be a sustainable solution as cannabis cultivation expands.
Guarding Against Ganja’s Greenhouse Gases
Although cannabis can absorb a remarkable amount of CO2 when planted outside, indoor cannabis production has a negative carbon footprint. According to data from the Smithsonian, it takes about 2 – 5 tons of CO2 to make just over 2 pounds of cannabis flowers. Researchers also highlight that cannabis cultivation now produces almost one megaton more CO2 in Colorado compared to the coal mining industry.
Again, the “simple fix” for these CO2 figures is to increase outdoor cannabis cultivation. In the same Smothosnian report, scientists claim Colorado could reduce greenhouse gas emissions by an impressive 96%. Even if indoor cultivators opted for greenhouses rather than standard grow facilities, it would cut CO2 by approximately 42%.
High-quality carbon air filtration is a must for cultivators who can’t switch to outdoor or greenhouse gardening. Some facilities have begun experimenting with “carbon scrubbers,” which help remove volatile chemicals before they exit a grow room’s ventilation system. These innovative filtration systems will decrease CO2 emissions and reduce the “odor burden” in neighborhoods close to cannabis grow facilities.
The Weight Of Weed Waste
Waste management is another major concern amongst environmentalists in the cannabis industry. A recent report from the CO Department of Public Health and Environment found that the state produces some 7.3 million pounds of cannabis plant waste annually.
In response to the increase in weed waste in the state’s landfills, Colorado opted to consider cannabis plant materials with zero THC content as viable for compost. This strategy seems to be a viable strategy to use cannabis that otherwise would have gone into the trash.
But it’s not just plant material contributing to cannabis’s massive waste problem. Remember that most manufactured cannabis items are often in plastic packaging. Also, many popular products like vape pens are single-use products, which has an outsized impact on the environment. Industry standards for biodegradable packaging and easier access to recycling services are necessary to reduce this looming threat.
Water consumption is another worry in the weed sector. However, recent studies from New Frontier Data strongly suggest cannabis doesn’t consume as much water as other crops. For instance, rice needs 5,830 billion liters annually, while cannabis only needs about 4 billion liters.
Although cannabis doesn’t need as much water, please remember the industry is relatively small compared with other crops. Also, since the weed market is in a growth phase, it will consume exponentially more water in the ensuing months.
Some indoor cultivators have begun experimenting with techniques like drip irrigation to deliver just enough water for optimal harvests. Researchers are also looking into whether water purification techniques like reverse osmosis are truly essential for high-quality cannabis yields. In many cases, researchers have found that tap water often has no ill effects on cannabis plants and helps conserve energy and water.
Federal Legislation Will Determine The Future Of Weed Sustainability
While many weed cultivators and researchers are interested in sustainability, there’s a lack of tools and knowledge for growing this crop. Not only is there little historical data on growing cannabis, it’s difficult for today’s scientists to start researching optimal cannabis cultivation. Environmental organizations are also afraid to study weed’s impact on the environment.
Even though CBD hemp is legal for cultivation in the USA, it will take greater federal legalization and investment in research to set the cannabis industry on the path toward a sustainable future.