Indoor farms need light—and a lot of it—to grow crops, but that energy adds up big time in terms of cost and environmental impact. A Pinkhouse is a new type of indoor farm that grows crops using pink-colored light. Rather than bathing plants with white light (which has all the colors of the spectrum), a Pinkhouse uses a mix of red and blue light. By not using all the other colors, indoor vertical farms can cut down on their power bill with low-energy LED lights that emit just the right shade of magenta.

To grow sufficient quantities of food and produce in an indoor farm, crops have to be stacked. But this also means that each shelf has to have its own light source in order for the plants to grow. All these lights add up quick and so does the power bill. A new wave of research shows that “pink” light – a mix of red and blue wavelengths is all that a plant really needs to grow. In the whole spectrum of ROYGBV, the O, Y, G and V aren’t really necessary for plant growth, just the R and B. Besides reducing the amount of power for the lights, the LED lights are cooler, which also reduces the cooling load.

Researchers at Purdue University are currently studying the use of red and blue lights on plants, but it’s already being used in a real-world indoor farm. Caliber Biotherapeutics grows plants for medicinal use and they have a 150,000 sq ft indoor farm in Texas that relies on this pink light. Stacked 50 ft tall, their indoor farming system grows 2.2 million plants with the red and blue LED lights, which was designed by EEA Consulting Engineers. “A photon is a terrible thing to waste,” says Barry Holtz, at Caliber Biotherapeutics. “So we developed these lights to correctly match the photosynthesis needs of our plants. We get almost 20 percent faster growth rate and save a lot energy.”

+ Caliber Biotherapeutics