Indoor cannabis runs on lights and air conditioning. Ours runs on the sun.
By Tyler Rumi
Indoor cannabis grows are some of the most energy-intensive operations in North America. Everyone in the industry knows it. Most consumers don't.
To put it into today’s context: indoor cannabis cultivation rivals data centres for energy intensity. The same data centres are making headlines and raising people's rightful concerns. Per square foot, an indoor grow uses roughly 40 times the energy of an energy-intensive hospital and 70 times that of a typical office building. Growing a single ounce of indoor cannabis releases the rough equivalent of 7 to 16 gallons of gasoline worth of CO₂, depending on local climate and grid.
That last bit matters in Canada. A recent study found that outdoor cannabis can be 6 to 10 times less carbon-intensive than indoor cannabis, and that BC is the most efficient province to grow in because of its milder climate and cleaner electrical grid. Where you grow makes a real difference before you even get to the method.
The reason indoor cultivation uses that much energy isn't a mystery. An indoor grow is, underneath everything, a big electrical appliance with some plants in it.
Roughly how the load breaks down in a typical indoor operation:
Grow lights: 35 to 45% of the total power draw, running 12 to 18 hours a day.
HVAC cooling: 30 to 40%, just to pull out the heat the lights emit.
Dehumidification: 10 to 20%, because plants release moisture, and it has to come back out of the air.
Air circulation: 5-10%; fans keep everything moving.
None of that is growing the plant. It's all just rebuilding, with machinery and electricity, the same conditions that exist for free outside.
We grow most of our cannabis outdoors on Salt Spring Island, BC. Gluerangutan, our flagship, is outdoor only. So is Timewarp. Outdoors, that entire list above goes away. No grow lights, because the sun is right there. No air conditioning, fighting the heat that the lights would've made, because there are no lights. No dehumidifiers, no climate to build and power. The plant gets light, weather, and a day-night cycle the way it has for as long as it has existed. We're not powering any of it. We're just letting it happen.
I want to be honest about what we give up, because it's real. The sun runs on its own schedule, not ours. We get one harvest a year, when the season says so. No, a fresh crop every eight weeks whenever we feel like flipping a room. A bad-weather stretch is a bad-weather stretch; we can't air-condition our way out of it. Indoor growing buys you control, and control has a lot of value. We just decided we'd rather take the season as it comes than burn the power to fake it.
Here's what I'd gently push back on: people assume that because indoor environments are more controlled, they must be better. More consistent, sure. But the cannabis plant didn't evolve under a metal-halide lamp. It evolved under the sun. When we let Gluerangutan grow outdoors in living soil, under real light, it comes back with the highest terpene load in our whole lineup, averaging about 4.5%. I don't think that's despite the outdoor conditions. I think it's because of them. The plant knows what to do with real sunlight in a way it never quite does under a fixture. In fact, we tried Gluerangutan indoors in the early days, thinking that a plant with such great scores outside might do even better indoors. The results were a flop: lower THC, lower terps, and a less happy plant and yield.
So when the talk turns to making cannabis greener, I'd just point to the simplest lever there is. The sun is free, it's already there, and it doesn't have a carbon footprint we're adding to. The most sustainable grow light is the one nobody has to plug in.
Tyler Rumi is co-founder and cultivation lead at GOOD BUDS, Canada's first licensed outdoor cannabis producer. He has grown cannabis in living soil on Salt Spring Island, BC, since 2017.
