Smart Farming

Salad in space

Bathed in shades of magenta and cyan, lettuce plants thrive under tiny lights in Cary Mitchell’s indoor horticulture lab without the benefit of sunshine. In this high-tech hydroponic growth chamber, Mitchell and his team have discovered that targeting plants with red and blue LEDs provides energy-efficient lighting for contained growing. It’s a discovery that could advance the development of crop-growth modules for space exploration while also making controlled-environment agriculture on Earth more economically viable.

Mitchell, a professor of horticulture and affiliate of the Center for the Environment, and Lucie Poulet, a former master's student, found that leaf lettuce thrived under a 95-to-5 ratio of red and blue light-emitting diodes (LEDs) placed close to the plant canopy. The targeted LED lighting used about 90 percent less electrical power per growing area than traditional lighting and an additional 50 percent less energy than full-coverage LED lighting.

The study suggests that the model could be a valuable component of controlled-environment agriculture and vertical farming systems in space and on Earth, Mitchell says.

"Everything on Earth is ultimately driven by sunlight and photosynthesis," he says. "The question is how we can replicate that in space. If you have to generate your own light with limited energy resources, targeted LED lighting is your best option. We're no longer stuck in the era of high-power lighting and large, hot, fragile lamps."

- Natalie van Hoose, Purdue News Service

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