The Lighting Challenges of Indoor Horticulture

September 8, 2016 By Carl Weinschenk


When energy managers think of lighting, it usually is within the context of properly illuminating offices, schools, factory floors and other facilities. That’s a big job. However, there is a small corner of the energy manager’s world where a unique use of lighting – and its relationship to its cost – is even more intense: Indoor horticulture.

The indoor growing industry is large and seems to be expanding. It is benefitting from the transition to LEDs. Today, Transcend Lighting posted results of the retrofit of the production facility of cannabis producer Ajoya, which is in Colorado. The results were stark: Replacement of the T5 fluorescent lighting with T5 LEDs offering the same illumination used half the energy. The annual reduction of 85,000 kWh earned Ajoya a rebate from Xcel Energy that paid for one-third of the project.

The use of artificial lighting to grow plants of course is nothing new. Like all lighting technologies, however, it a quickly evolving area. An article at LED Professional suggests how quickly things are moving. The piece focuses on the benefits of supplementing LED systems with cadmium-free quantum dots in vertical grow environments. At the beginning of the piece, the writer highlights the unique advantages of LEDs for indoor growing. In addition to the usual cost benefits of LEDs, the story said, this form of lighting can be closely optimized to the precise color needed by a particular plant.

Earlier this summer, California LightWorks introduced SolarSystem. The platform, according to the company, uses advanced control technology to tune LEDs to optimize the spectrum of light delivered based on the type of plant and their phase of growth. The company claims that the approach increases yields from the plants while reducing energy costs and improving return on investment.

LED Grow Lights Depot digs deeply into definitions that must be understood by energy managers in horticultural settings. The post says that photosynthetic photon flux (PPF) defines how many photons are emitted by a light source per second. photosynthetic photon flux density (PPFD) describes the density of photons being distributed by the fixture to a square meter per second. Daily light integral (DLI) describes the delivery of photons on a day (or, more technically, a “photoperiod”). These and other measures described in the post directly relate to the ultimate cost of lighting for the facility:

Every aquarium and lighting system is different, and there are numerous factors that affect the total amount of light which is delivered by a light fixture. So, while ‘lumens’ was easy, it really had no consistent link to the amount of light you were delivering to your plants and algae. PAR, PPF, PPFD. and DLI are precise and consistent terms and measurements used by scientists, algae researchers, horticulturists and labs around the world — but they can be difficult to memorize and grasp.

Clearly, horticultural lighting is complex. That means that buying systems will be as well. For energy managers, the task is even more difficult: The goal isn’t just to find the system that successfully mimics Mother Nature. It is to do so at the lowest possible cost. Fluence offers insight into some cost issues related to horticultural lighting.

Those interested in horticultural lighting should consider these two resources. LED Magazine is sponsoring the Horticultural Lighting Conference on October 12 at the Palmer House Hilton Hotel in Chicago. More immediate information can be garnered from a special section on horticultural lighting at Greenhouse Management. The introduction offers definitions of 15 important terms. The intro links to an infographic that featured reported on a survey that found, among other things, that 70 percent of respondents grow ornamental crops and 40 percent edible crops.

2 comments on “The Lighting Challenges of Indoor Horticulture

  1. Very fascinating read. I wonder if we can provide the optimum kind of lighting to different people rather than providing the same thing for everyone.

  2. Great article. I’m curious how you found your sources for some of this information and how you chose to feature the light brands that you did. A lot of companies have really made some big leaps and bounds this year. HydroGrow is about to come out with some big leaps as well.

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