Many Clevelanders were mystified by a purple light in the sky when Green City Growers turned on its new LED lights in 2018.
Photo courtesy of Green City Growers

On cloudy days, growers at Green City Growers in Cleveland kick on LEDs to give their lettuce and basil an extra boost, speeding up the growing process and improving the plants’ look and taste.

Green City Growers encompasses 3.5 acres of indoor growing space and producing millions of nutritious plants annually. The cutting-edge urban hydroponic greenhouse — headquartered in the Central neighborhood on Cleveland’s East Side — is counting on high-tech LED lamps to increase plant production during Northeast Ohio’s long and gloomy winters.

GCG installed 1,200 LED lights at the beginning of 2018, switching from the metal halide and high-pressure sodium (HPS) lamps it had been using for the previous four years.

“When we opened [in 2013] there wasn’t a version of LED fixture that was commercially viable for a facility as big as this one,” says John McMicken, CEO of Evergreen Cooperatives, which includes a solar energy business and laundry co-op along with Green City Growers. “We started with high-pressure sodium, which has always been the tried-and-true version of agricultural lighting.”

LEDs mean plant food

Inside the massive greenhouse, the new lighting system helps cultivate 3 million heads of lettuce and 400,000 pounds of basil annually, with GCG’s hearty greens sold to local and regional restaurants, grocery stores and food processors.

Unlike traditional greenhouse lamps, LED lights save energy and are more easily absorbed by plants during the photosynthesis process. Pigments in the leaves harness the LED color spectrum — which growers change onsite depending on the weather — mimicking the sun’s rays and ideally resulting in the best possible produce.

“LEDs give us the ability to control the intensity of the lighting, where HPS lighting is either ‘all on’ or ‘all off,’” says McMicken, who also currently serves as the greenhouse’s interim president. “We might need more light at the younger side of the crop, and less light at the more mature side. With LEDs, every fixture is IP addressable via a Wi-Fi network, so we’re able to control groups of lights at a time. We tell our growing team how much light to add depending on the amount of natural light available, which changes throughout the day. Now we have more flexibility on how and when to use the lights based on what Mother Nature gives us.”

Specific plants require individualized wavelengths from the light spectrum, McMicken says. Younger crops benefit from red lighting, while mature plants that don’t need as much light like the blue spectrum. Good lighting is a particular boon for basil, driving oil content within plant tissue to turn out a nutrient-rich emerald green blend.

“LEDs help us ensure year-round consistency in size as well as flavor and color,” McMicken says. “That’s mission-critical for [our customer] Nestlé that’s selling high-end recipes.”

Testing, testing

In 2017, Green City Growers evaluated LEDs from 10 different manufacturers, choosing a Canadian company specializing in outdoor- and water-rated fixtures. Many LED systems are air- or fan-cooled, which poses a challenge for a high-humidity greenhouse environment.

Installation presented an immediate challenge, considering an operation where plants at various stages of growth are floating in shallow pools of water in a deep-flow technique system. Eschewing ladders or lifts, the Green City Growers team instead built an aluminum boat ramp across a wheeled track, sliding the contraption back and forth to mount lights along the ceiling.

Though LEDs are costly upfront, the potential for yield increases is reason enough for the investment, McMicken says. An improved growth process means more produce for customers and revenue for an employee base in need of living-wage jobs. Green City Growers shares profits with its 45 employees, carrying a larger goal of wealth creation for the economically depressed community in which it resides.

The greenhouse is currently training employees on the lighting system, providing additional transferable skills to further workers’ high-tech agriculture careers.

“We’re always looking for ways to diversify and expand the career path of our employees,” McMicken says. “This [LED system] has absolutely opened up new doors for us.”

Now that the greenhouse is 100 percent LED-lit, McMicken is excited to witness the impact of next-generation lighting technology on his operation’s bottom line. Based on a projected yearly 15 percent increase in crop production, the co-op CEO forecasts a $600,000 uptick in annual revenue, heralding what he believes to be a bright future powered by LED lights.

“It’s a game-changer for the business,” McMicken says. “I envision most if not all growers converting to LEDs if they haven’t already. In a few months, we’ll know the true impact.”

Douglas is a Cleveland Heights, Ohio-based freelance writer and journalist. His work has been published by Midwest Energy NewsCrain’s Cleveland Business and The Chronicle of Higher Education.