Olivia Marder on the wonders of soil-less growing.
Up until recently, if someone were to have asked me, “What does a plant need to grow?” I probably would have answered, “soil, water, and sunlight.” Sounds like a pretty standard response, right? But what if I told you that you could reduce this list even further—that plants can actually grow without soil? It turns out that plants don’t need soil to grow; rather they need the nutrients found in that soil. Enter hydroponic gardening. In a hydroponic garden, plants grow in an inert medium (which is just a fancy way of referring to a material that won’t break down or decay quickly—such as gravel, clay balls or even coconut husks). This medium supports the plants’ weight while also stabilizing them so that they grow upright. The plants and medium are placed in a hydroponic system, like the one seen below, which pumps nutrient-enhanced water throughout the structure. Unlike traditional, soil-based plants, which spend most of their energy developing huge root systems to search for water, hydroponic gardening offers increased efficiency by delivering nutrients and water directly to the plants’ roots. You may be wondering, “Where do urban farms fit into this equation?” BrightFarms represents an encouraging example of the intersection between hydroponics and urban farming. Based in New York City but operating all along the East Coast, BrightFarms builds hydroponic greenhouses at or near supermarkets in order to grow “year-round local produce that prioritizes our farmers, our food quality, our health, and our environment”. According to BrightFarms, “hydroponics are ideal for rooftops… because they have such high yields and are less heavy than soil-based operations. They also use far less water, while diverting storm water from the sewer system, which can overflow during heavy rain”. Currently, BrightFarms owns and operate 6 hydroponic greenhouses, each of which partners with a local supermarket. Last April, BrightFarms announced exciting plans to build the largest rooftop farm in the United States—and maybe even the world—right here in Brooklyn! Upon completion, the Sunset Park farm will measure up to 100,000 square feet of rooftop space and offer fresh, hyper-local produce to New York City.
Despite the added benefits of urban hydroponic farms—such as reduced weight and water usage, increased yields, and water diversion—many remain skeptical about hydroponic farming techniques. The biggest argument against hydroponics is energy. Instead of obtaining nutrients from the soil or the sun, hydroponic farming requires the addition of artificial nutrients to the water supply, which then need to be pumped and filtered through the system. However, with a reduction of transportation distance by growing the crops directly on top of or in the vicinity of supermarkets, I’d say BrightFarms offers an innovative approach to reducing its operations’ energy footprint. BrightFarms and other urban farming ventures, including our very own garden here at NYU, demonstrate that the urban agriculture revolution is gaining traction. I, for one, can’t wait to join the movement by farming this semester at our NYU farm! Once the long awaited spring season hits, I’m eager to gain a hands-on understanding of urban gardening. Specifically, I look forward to making a more informed distinction between BrightFarms’ hydroponic, rooftop approach to farming in our soil-based, ground-level garden at NYU. Some questions I hope to answer are: “Can healthy plants really grow without soil?”, “Is hydroponics more or less energy efficient than traditional farming (no-inputs) techniques?” and “Do these contrasts even matter?” In the end, both techniques highlight a shift in agriculture practices towards a more local, sustainable food system. Whether you’re a believer or a traditionalist, one thing is certain—BrightFarms’ initiative demonstrates the promise of the ever-expanding local food network!