Growing cannabis indoors emits
6.5x
more greenhouse gases per kilogram than growing cannabis outdoors.
Growing cannabis indoors emits
6.5x
more greenhouse gases per kilogram than growing cannabis outdoors.
Let’s put it in context…
Producing one 1-gram joint indoors emits as much as driving 12 miles, compared to 2 miles for outdoor-grown cannabis.
The emissions released from producing one 1-gram joint indoors are equivalent to the emissions released from producing 321 cigarettes!
Indoor cannabis grow operations use energy-intensive precision farming to maximize yield:
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Generating the amount of energy these facilities need emits substantial greenhouse gas emissions.
Per square foot in a year 
, an indoor cannabis factory will use 8,540 kbtu which is...
40x more than a 
, or
100x more than a typical 
.
That begs the question: if their PG&E bills are so high, why are they growing indoors at all?
Just as consumers expect the same taste from each Hershey bar, they expect a consistent high from a given product. But outdoor grown cannabis can vary by crop due to changing weather and soil.
Indoor grows can boost THC levels, but studies show effects plateau above levels already reached by high THC outdoor cannabis, making the extra potency more marketing than meaningful.
Indoor cannabis yields 5–6 harvests per year, far more than the 1–2 from outdoor farms. But with supply now outpacing demand, a lot goes to waste. Does the industry need so many harvests?
A Santa Barbara grower found they’d need 25x their roof area in solar panels to power their indoor farm, an unrealistic and land-intensive solution.
Facility roof area:
Solar panel area needed to power the facility:
There are sustainability upgrades like composting waste, switching to LED lights, or growing lower-energy strains, but none have the impact of one simple change: Growing cannabis outdoors.
Emissions of today's cannabis industry:
100% outdoor cultivation --> 75% decrease
100% solar + electrification --> 49% decrease
Shifting indoor to greenhouse -->25% decrease
Electrification with LEDs + heat pumps --> 10% decrease
Composting plant waste --> 2% decrease
*These are not additive. Solar considered as an impractical thought exercise.
Indoor grows can’t decrease their emissions to the level of outdoor cultivation. No need to burn
fossil fuels when you have the sun 
.
Yes, outdoor grows generally use more land and water than indoor growing facilities and these are important tradeoffs to consider.
Let’s see how much land, water, and power it takes to grow indoors versus 100% outdoors.
Indoor: 66%, Outdoor: 34%
Ask your dispensary for sun-grown cannabis. Some farms even label their products as such—support them with your dollars.
It’s tougher. But you can still make a difference. Talk to your dispensary, ask about growing practices, and let your elected representatives know you care about sustainable cannabis.
Federal legalization would allow interstate cannabis sales, letting states with good outdoor growing conditions (like California) supply sun-grown cannabis to those states that can’t grow outdoors easily. Contact your U.S. Senators and Representatives to voice your support for federal legalization.
Huge thank you to Dr. Evan Mills, Lawerence Berkeley National Laboratory
Mills, E. (2025). Energy-intensive indoor cultivation drives the cannabis industry’s expanding carbon footprint. One Earth, 8(3), 101179. https://doi.org/10.1016/j.oneear.2025.101179
Thank you to the Noun Project for supplying icons.