LEDs in Horticulture
Philips Lighting has opened the LED-centric GrowWise Center in Eindhoven to study light recipes for plant growth while Purdue University has conducted research on using LEDs to cultivate plants during deep-space missions.

Philips HTC City Farm Eindhoven
The Philips GrowWise City Farming research center in Eindhoven, the Netherlands has opened for research into increasing agricultural yields using LED horticultural lighting in precise mixes or recipes of color and intensity. Purdue University, meanwhile, has announced the results of a research project growing lettuce in tight vertical layers with LEDs placed near the plant canopy to model what might be the tight space that astronauts experience on deep-space missions such as a trip to Mars.
Philips High Tech Campus
The GrowWise Center is a 234-m2 facility located at the Philips High Tech Campus in Eindhoven and will concentrate research on growing leafy vegetables, strawberries, and herbs using artificial LED horticultural lighting. The center will also try and find ways to grow wheat, potatoes, and other carbohydrate-rich crops indoors.
SSL and horticulture in space
Moving to a study in space, LED horticultural lighting may be the only option for astronauts to grow fresh vegetables, and indeed survive, during long-term missions. Purdue University professor of horticulture Cary Mitchell has led a research project growing lettuce in conditions that might be similar to those on a cramped spacecraft.

Targeting hydroponically-grown leaf lettuce with red and blue LEDs saves a significant amount of energy compared with traditional lighting. (Purdue University/Lucie Poulet)
The research notes that a trip to Mars would require 1000 days or more, as well as more food and water than current space vehicles could carry. Crews manning such missions, including a potential stay on Mars, or even the moon, would need to grow their own food.
“Everything on Earth is ultimately driven by sunlight and photosynthesis,” said Mitchell. “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.”
The Purdue work used a mix of 95% red and 5% blue LEDs placed immediately above the canopy of the lettuce. The work indicates that specially engineered LED horticultural lighting is effective in producing lettuce using 90% less energy than legacy sources and even 50% less energy than broad-spectrum LED lighting.
“If we can design a more energy-efficient system, we can grow vegetables for consumption for longer space travel,” said Lucie Poulet, a masters-degree student that worked on the project. “I can imagine a greenhouse on the moon.”
Next, Mitchell will lead further research in optimizing the light recipe. The objective will be identifying when to increase or decrease lighting relative to plant growth stage to maximize yield relative to energy used.
Purdue has been at the center of a number of LED-centric horticulture projects. Mitchell previously led research looking at optimized artificial lighting for tomato growth.
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