Energy Efficiency in Indoor Cannabis Cultivation: Optimizing Light

In our upcoming March/April issue of Cannabis Science and Technology, we will cover various factors in efficiency in indoor cannabis cultivation.

In this video excerpt of our interview with Zacariah Hildenbrand, PhD, partner of Medusa Analytical, and a director of the Curtis Mathes Corporation (OTC:CMCZ), we discuss how lighting is used in cultivation.

Erin McEvoy: Does light spectrum impact energy efficiency for indoor cultivation?

Zacariah Hildenbrand: Light spectrum and light intensity are single handedly the two most important variables in cultivation in general. They drive a wide array of biological processes, and so it stands reason if you don't have enough light, enough intensity, your plants are not going to thrive, and maybe they don't even survive. If you have too much intensity, you could get photobleaching, so you have to have a healthy balance there. In the context of indoor cultivation, you're looking at putting your lights the appropriate distance from your plants at the various stages of cultivation.

Spectra is an interesting one. For the longest time, we had people using ceramic metal halides and also high pressure sodium lights. So you're trying to get all of the photons within the photosynthetic range of 400 to 700 nanometers, the broad spectrum of colors. It's just like anything in life: all the colors make things beautiful. So what would happen, traditionally, is you have your ceramic metal halide, which is on the lower end of 400 or 500 for your blues and greens and then that would be used in veg. Then people would switch over to the high-pressure sodium and more of your oranges, ambers, and reds to closer to 600 or 700 and that's where you would flip into flower. From there, we now have full spectrum LED lights, which cover the full spectrum of light, so you don't have to mess around with different lights and different bulbs at different times. It kind of simplifies things for everyone. Also, a nice little benefit of LEDs, they're incredibly efficient, so you don't produce as much waste heat, which comes out at 850 nanometers. Managing heat is a big factor in cultivation. It's a big cost that people have to account for. And so if you can reduce your heat production while producing as many photosynthetic photons as you can, and a wider range of them, not just red and blue, like we initially saw that came out with LEDs, where it was like, “the phytochromes just absorb in red and blue, and so that's all you need.” No, you need the full spectrum of photons here. So yeah, fortunately, we've made a lot of technological advancements in that realm.