Pink light

So, you’ve heard of urban farming and vertical farming, right? Right! Basically, a bunch of smart and green-thumbed people (aka horticulturists) get together to build incredibly tall farms atop, and in, city buildings. Most vertical farms are constructed to get healthy, fresh food into urban areas. However, it’s beginning to look like covering gigantic buildings with green plants may not be as efficient as once thought. And according Cary Mitchell, horticulturist at Purdue University, skyscrapers aren’t the most efficient vertical farming complexes.

In an NPR article titled “‘Vertical ‘Pinkhouses:’ The Future of Urban Farming,” Mitchell said that, in fact, skyscraper vertical farming is “absolutely ridiculous from an energy perspective.”

Mitchell said that vertical farms actually may perform better in large warehouses in suburban settings (basically, suburbia = cheaper real estate and electricity.) And Mitchell explained that these warehouses won’t be outfitted with the run-of-the-mill fluorescent lamps. Instead, the sprawling, green spaces will feature blue and red LEDs.

According to the article, lighting vertical greenhouses is a tough gig. When plants are placed on top of each other, some plants are naturally going to shade other plants. To remedy that, artificial lighting is used, but it can be pricey. But, according to Mitchell, plants only really need blue and red wavelengths. Plants absorb and use these wavelengths most efficiently. Also: LEDs are energy efficient, can be turned to specific wavelengths, and LEDs run cooler, and therefore, can be placed closer to plants.

Currently, Mitchell and one of his graduate students are running growing experiments with the blue and red, specialized LEDs. While Mitchell’s experiment only examines how well LEDs do as a supplement to natural light – not a complete replacement – Barry Holtz, from Caliber Biotherapeutics, is currently growing a closed, indoor plant factory.

While this type of indoor farming is nowhere near as efficient as traditional farming for most crops, Holtz explained that for certain specialty crops, it’s quite efficient when it comes to electricity and water.

Image: Stefan