Today there are many options for cannabis lighting fixtures available, with more fixtures regularly hitting the market. A deeper understanding of lighting spectrum can save you thousands of dollars by allowing you to efficiently select a spectrum and wattage for your plants and environments’ specific needs. In order to raise awareness and empower growers to make scientifically based lighting decisions, we thought it would be helpful to offer a general overview of what light spectrum is and how it’s relevant.
Dan Gustafik, Founder of Hybrid Tech explains further, “There has been limited research, but no PhD led, peer-reviewed white paper identifying the phytochrome response of cannabis. Phytochrome is a photoreceptor and pigment that plants, bacteria and fungi use to detect light. Cultivators of basil, microgreens and every other commercial crop have the phytochrome response documented at each stage of growth. This allows growers to tailor the lighting system to the desired effect.”
Tyler Mentel, Head of Design at Hybrid Tech adds, “The biggest hurdle with designing cultivation facilities is attempting to create a design with almost no data available for cannabis. No other industry makes design decisions without data to backup said decision. Just the other day, we were pitched a LED lighting solution without any light measurement sphere tests in their cutsheet. How can you sell something that claims amazing photosynthetic spectrum without any data? It’s completely absurd. I hope in the near future that we can place the Federal regulatory hurdles aside in an effort to collect unbiased scientific data so we can make educated decisions about effectively cultivating this plant.”
What should you be looking for in a lighting spectrum? First, let’s define some terms:
- Spectrum – The lighting spectrum is composed of all the different colors you can see, and lots of light that you can’t see. Plants evolved for millions of years in sunlight, and each has a particular preference and utility for spectrum of a particular blend. Typically, you’ll want a more blue spectrum for the vegetative state, and a more red spectrum for the flowering state.
- Efficiency – micromol/joule is how efficient your fixture is at converting electrical energy into photons. Joules are the measurement of energy, micromols are the measurement of light quantity. This is the amount of energy it takes to produce a certain amount of photons.
- PPFD – Photosynthetic Photon Flux Density is a measurement of photosynthetic active radiation (PAR). This is the number of photons in the 400-700 nm range received by a plant surface for a specified amount of time per a given area.
- UV – Ultraviolet light is part of the spectrum naturally produced by our sun, and until relatively recently, had not been incorporated into modern indoor lighting spectrums. By incorporating UV light, growers seem to be achieving some benefits. Note the three types of UV light below:
- UVA = 400nm-315nm
- UVB = 315nm-280nm
- UVC = 280nm-100nm (doesn’t penetrate our atmosphere, ignore for grow purposes)
After extensive trial and error, Hybrid Tech has found that the most powerful lights are not actually guaranteed to produce the best plants or yield the most flower.
Dan explains, “Contrary to what most growers believe, efficiency and yields do not seem to scale linearly with PPFD. Our most surprising discovery to date has been the 1,000 watt HPS vs the 630 watt CMH fixture trial. We have had many clients replace a 1,000 watt HPS with a 630 watt CMH. The 1,000 watt produces 1500-1700 PPFD while the 630 watt CMH produces 860 PPFD. These clients have reported a slight increase in cannabinoid and terpene potency, while yields remained consistent. The CMH fixture appears to replicate the spectrum where cannabis optimally performs in vegetation and flower cycles.”
Integrating UV spectrum into your garden is critical. Dan notes, “The UVA spectrum seems to trigger an end-of-life response in cannabis. A near death phytochrome directs the plant’s energy into its’ reproductive processes, either producing seeds or maximizing seedless flower.”
If you’d like to learn more about LED lighting solutions, including the Oreon Grow Light 2.1, click here.