Cleveland night owls and early risers began noticing a bright, eerie purple glow in the skies over the Ohio city about a month ago, particularly on cloudy nights.
But what was causing the inexplicable magenta light?
Amateur sleuths’ theories, shared on social media and in the news, ranged from the obvious to the extraterrestrial: Was it aliens? The Northern lights? The glow of a digital billboard? A new nightclub near Diamond Avenue and East 55th Street, where the lights had been spotted?
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The real explanation was hardly spooky.
Several months ago, Green City Growers — a greenhouse in the city — switched to purple LED lights, which get turned on each morning around 4 a.m., Cleveland News 5 reported. The glow from the large greenhouse’s lights has been perplexing neighbors and commuters on Interstates 490 and 77 ever since.
“These LED lights help the plants grow healthier and faster,” explained general manager Jeremy Lisy, according to News 5. “For example with traditional lighting, it would take about 30-35 days to harvest basil, but with LED lights that time is reduced down to around 28 days.”
Lisy told the TV station he’d been waiting for people to start asking about the purple glow.
Plants performing photosynthesis can most efficiently soak up red and blue light, so the pink-ish, purple-ish LED lights are a good way to meet the plants’ light needs without using too much power, NPR reports.
The purple lights are in the local news again this week, after people outside the Quicken Loans Arena and elsewhere started sharing photos of a very magenta sky — with some wondering if it was from a UFO, FOX 8 reports.
Others already knew the greenhouse was the culprit.
Green City Growers is a cooperative that raises produce without pesticides all year round at its 3.25-acre hydroponic facility in Cleveland, making it the largest food-growing greenhouse in the core urban area of any U.S. city, according to the cooperative’s website. It opened in 2012.
The greenhouse grows a million heads of lettuce yearly, as well as other produce ranging from micro-greens to herbs. That produce gets delivered to local restaurants, grocery stores and elsewhere in the Cleveland area.