Why is this so critical to vertical farming?
Before diving into the basics of LED lighting, let’s touch on why vertical farms require such a massive amount of light. Though a simple problem to understand, there is no universal lighting solution to efficiently illuminate multi-level farms because higher levels shade lower ones. Essentially, any move to intensify the number of seedlings per square foot, a primary function of vertical farming, is going to increase the shade over seedlings already in place as in the image from VertiCrop below.
As a result, prominent critics cite lighting as the main limiting factor any successful vertical farm would have to overcome. One such critic is Dr. Ted Caplow.
I first ran into Caplow’s work after learning about the Science Barge experiment he was running in New York. Caplow and his team were trying to figure out exactly what it would take to reach efficient, sustainable production in the middle of a city. The barge was a success, but it hinted at failure for vertical farming.
Based on his experience, Caplow came up with a rough estimate for calculating lighting requirements for hydroponic growing facilities fueled by solar panels (like vertical farms). Basically, he estimates that to light a single layer of plants using energy exclusively from solar panels requires an area 20x larger than the square footage of that layer.
With improvements in LEDs and solar panels, Caplow’s estimates may soon be wrong if they aren’t already.
But first thing’s first: what are LEDs and what exactly is efficiency?