Seeing the light

LED lighting could reorganize cannabis grows from the ground up


Since the days of prohibition, the light source of choice for indoor cannabis grows has been high pressure sodium (HPS) light bulbs. 

HPS bulbs have been the standard for good reason: They last for a long time, they put out the most lumens, and generally, they have been the most efficient way to mimic sunlight inside. 

But that is starting to shift. As technology improves and as businesses put more value into sustainable practices, light-emitting diodes — or LEDs — could reorganize grow rooms from the ground up. 

“LED lighting technology for the purpose of indoor agriculture has made giant technology leaps and bounds in the last 5 to 10 years,” says Kaitlin Urso, the environmental consultant, project manager and small business assistance program specialist for the Colorado Department of Public Health and Environment (CDPHE). “A lot of cultivators are starting to see the light with LEDs.” 

Urso works with a lot of cannabis grows across the state, striving to improve sustainability within the Colorado industry. She recently spearheaded the National Cannabis Industry Association’s Environmental Sustainability Report, which recommends grow operations start implementing LEDs wherever possible — not just to save energy for the planet, but to save money for the business and even to double their cannabis production with the same growing area.  

Now, some will still argue (correctly) that LEDs aren’t as powerful as HPS bulbs and that they cost more up front. So why spend more for something that doesn’t crank out as many lumens? What makes LEDs so much better?

First, Urso says, because LEDs last so much longer than HPS bulbs do. A typical HPS bulb will last for around 24,000 hours, over which time their brightness will slowly degrade. HPS systems also only put out a limited spectrum of yellow and orange light, which they emit 360-degrees around. 

LEDs, by comparison, last for between 50,000 to 100,000 hours, their brightness doesn’t degrade, their light is directionally focused and they don’t contain toxic heavy metals like sodium. LEDs also use 70% less energy than traditional HPS systems, meaning even though it requires more LEDs to supply a grow with sufficient light, they’re still a more efficient option — one that will shave off a chunk of a cultivator’s energy bill. 

The biggest and most exciting way in which LEDs could change the business of growing pot, though, is their potential for vertical gardening. Because HPS bulbs emit 80% of their energy via heat instead of light, they have to be kept at a distance from the plants they’re growing — and because heat rises, that makes the prospect of stacking grows almost impossible.  

“You’re basically baking your plants with their own lights, and the levels of lighting underneath them as well,” Urso explains. 

LEDs emit almost no heat, so they can be kept very close to the plants. That means cultivators could stack grows, multiplying their production and thereby their revenue. 

“Talk about getting the most out of your resources; you can basically triple the footprint of your warehouse by going vertical,” Urso says. “That’s a huge advantage.”

Chris Baca, head grower at The Clinic, has been experimenting with LEDs for over a year. He admits that as the technology has gotten better, they’ve become a much more reliable and even a more productive method of lighting. 

“The newer LEDs are getting so cool nowadays, they produce so much spectrum [of light] that the plants grow so much quicker,” he says. The LEDs can be dialed in to produce exactly the spectrum of light that would be outside during a certain time of day, during a certain time of year. That allows cultivators like Baca to mimic the different grow cycles of the plant almost precisely, indoors. 

“You can use those spectrums to dial in your settings to mimic say, the veg cycle of your plants, or the flower cycle,” Baca explains. “Flower cycles are going to have a lot more of the red and orange spectrums because that’s supposed to mimic fall-time.”

Currently, The Clinic’s grow only uses LEDs in the “veg room.” The massive flower room still uses HPS bulbs — simply because that’s how the grow was originally designed, Baca says. Switching everything over to a fully LED flower room, at this point, simply wouldn’t be practical. Not for The Clinic, at least. 

But Baca says there’s no reason not to design new grows with LEDs and vertical gardening in mind. 

Urso points out that this isn’t a transition that cultivators need to make all at once, or even fully. Grows that are currently using HPS systems shouldn’t feel daunted by the prospect of switching their entire grow over to LEDs in one massive overhaul, she says. They can take the same approach as Baca has, implementing them where possible, still saving money, increasing their sustainability and reducing their carbon footprint. 

“It’s OK to for it to be a slow transition and to work your way into it … spreading out the cost slowly and adapting,” Urso says. “Then maybe one day [you can have] a fully functional LED grow operation.”