When Colorado legalized recreational marijuana no one would have guessed that it would end up as a gateway to experimenting with light bulbs. Plasma lights, induction lights, LED, fluorescent — you name it, Colorado Harvest Company has probably tried it.


“Really anyone who will give us a light to test out, we’ll test it out,” said CEO Tim Cullen. Over the years he’s looked for countless ways to improve efficiency.

The cramped windless rooms of their warehouse, humming with energy-intensive air conditioners and artificial lights, is how most Denver pot growers cultivate cannabis. As LEDs have swept homes, street lights and auto headlamps, marijuana growers haven’t been as quick to swap out their power hungry high-pressure sodium bulbs.

Changing out light bulbs doesn’t sound like a big deal, but it’s a huge win for growers and the city of Denver. Between 2012 and 2013, the city found that marijuana grows accounted for an interest-piquing 0.5 percent increase in energy use.

“It raised a lot of eyebrows,” said Emily Backus, a sustainability advisor with the Denver Department of Environmental Health. “It helped us push forward and say ‘we need to keep working on this.’ ”

For its part, Denver has been busy promoting sustainability practices among marijuana growers. A working group was started in 2015 to discuss it. A new city report explains how the industry can save energy on lights and cooling. Another report, expected from the Colorado Energy Office in the fall, should further detail energy used for indoor, outdoor and greenhouse marijuana grows.