Skyscraper farms seem like a thing of the future: Lettuce growing in windowless rooms under red-tinted LED lights while scientists check nutrient levels and calculate optimal harvest times. Basil plants stacked 10-feet high. Tilapia swimming in large troughs. While these images may contrast with our romantic notions of farming, the truth is that intensive indoor farming isn’t just a sci-fi fantasy – but a thing of present. There are already indoor farms cranking out 10,000 heads of lettuce a day.
photo by Plant Chicago, on Flickr
During the past decade, enclosed vertical farms have popped up around the world, from Singapore, to Japan, to the United States. These farms strive to grow fresh produce in indoor settings and to fill gaps in local food production. In a world of rapid population growth, growing food insecurity, and global climate change, this type of innovation in agriculture seems like a good thing. But for all the promise that vertical farming may hold, it also raises serious questions about energy-use, food justice, and the fundamentals of how we want our food to be grown.
The first question is: What exactly constitutes a vertical farm? Indoor vertical farms come in many different shapes and sizes, but generally speaking, they are “vertical” because they stack plants from floor to ceiling (often in several stories of a building). Some are constructed in abandoned warehouses, while others, like the Plantagon under construction in Sweden, are stunning examples of modern architecture. Regardless of size and shape, they generally employ one of three technologies: aquaponics (growing plants adjacent to fish, and using the nutrient rich water from the fish tanks to fertilize plants), hydroponics (growing plants without soil, in sand, liquid, or some other solution), or aeroponics (growing food with roots suspended in the air).
Using these indoor technologies, farmers are able to grow food just about anywhere, allowing for “ultra-local” farming.
“There are a number of factors that go into the farm and why we do what we do, and the majority of it has to do with being able to provide local produce to people and to customers that otherwise, traditionally, especially in the Midwest, are getting products that are sent to them, shipped for thousands of miles, and to actually get from harvest to someone’s table takes a significant amount of time,” says Mark Thomann, chief executive officer at FarmedHere, a 90,000 square foot vertical farm in Illinois. “What we do is we harvest, we distribute to our customers… and in many cases our product is actually on the store shelf in 24 hours. So that is a big deal. Our greens… travel less than 15 miles from farm to shelf, compared to an average of 2,000 miles for a head of lettuce, for example.”
In addition to the ability to produce local food just about anywhere, vertical farming enthusiasts also point to a number of additional environmental benefits. According to the Association for Vertical Farming, a nonprofit industry group, indoor farms require 98 percent less water than traditional farms, 70 percent less fertilizer, and no pesticides whatsoever. Because plants also have faster growth rates, indoor farms provide higher yields per square foot and less farmland is needed, leaving more land available for native plant and animal species.
When it comes to FarmedHere, these numbers seem to be fairly accurate. Thomann notes that their farm conserves roughly 97 percent of the water used per farmed acre and that the FarmedHere yield is twelve times that of a traditional farm. The high yield can be attributed in large part to the controlled environment. “Generally, 90 percent of our crop succeeds,” Thomann says. “Unlike traditional farming, where you have other elements like droughts and so forth that impact the production itself, in a controlled environment, from the time we put the plant in our row bed to harvest, it takes significantly less time.”
Water savings are one thing, but energy use is an area where indoor farming gets complicated. Although there are some vertical farms that use natural lighting, most are housed in large buildings and rely on artificial lights to spur photosynthesis and grow those big, leafy greens you find in your local grocery store.
And that energy use can really add up. “We calculated, for example, that to grow the US wheat crop, to produce the same amount of wheat grain production that we have today in a vertical farming scheme of a series of many, many buildings, would require something like eight times the total US electricity production,” says Stan Cox, a senior plant breeder with The Land Institute, an organization that promotes alternatives to destructive agricultural practices. The Association for Vertical Farming notes that indoor farms can employ renewables to achieve a reduced carbon footprint, but this doesn’t seem to be the industry norm.
Recent advances in LED technology have encouraged several farms, including FarmedHere, to switch from fluorescents to energy-saving LEDs. The savings can be substantial – LEDs require roughly 50 percent less energy than their fluorescent counterparts. What is more, they don’t generate a lot of heat while burning, eliminating the need for large cooling systems to maintain a temperature controlled environment.
These lighting-related advances are promising, but the bottom line is that sun-grown veggies are still more energy efficient than those grown under artificial lights. “I think we need to take as much advantage of free sunlight as we can before we start growing plants under artificial lights,” Cox says. “Even if it is LED efficient light, that still isn’t free energy.”
Aside from energy use, another major issue with indoor farming is cost. Land is expensive in urban areas, and constructing a farm-ready skyscraper or converting an abandoned warehouse isn’t cheap. These costs have implications not only for the economic viability of indoor farms (most vertical farms in production today are not profitable), but for their potential to bring affordable food to low-income urban communities.
“It depends on who [indoor farms] are supplying the food to,” says Danielle Nierenberg, president of Food Tank, a nonprofit think tank focused on innovative solutions to hunger, food, and agriculture issues. “If it’s Michelin star restaurants, that’s great because they can make a lot of money, the farmers themselves. But what we really need is affordable, accessible food for a lot of low-income communities in urban areas, and I don’t know if these skyscraper farms can do that. If they can, there is some real opportunity there, but you don’t see a lot of that.”
This is a challenge that FarmedHere has struggled with. “Our cost of goods currently needs to be reduced so we become more viable as a solution to food desserts and things like that,” Thomann says. “We aren’t there yet. But over time, that will change.”
Another limitation on the viability of vertical farming is the type of plants that can be grown. At the moment, the range of produce that can be efficiently grown in vertical farms is very restricted – most farms focus leafy greens like lettuce, basil, and kale, which require significantly less light than grains, legumes, or fruit-bearing plants. FarmedHere also grows a few tomatoes and strawberries, but admits that vertical farming isn’t optimal for these plants. This is a real limitation. Fresh lettuce is great, but it isn’t a particularly nutrient-dense food.
Outside of these economic issues, the community-building potential of a traditional urban garden versus a towering skyscraper is also something communities must consider. “[Vertical farming] gets to the question of how do we think about farming, and what should agricultural landscapes look like, because agriculture is not just about producing food and calories, it’s about contributing to landscapes, and regenerating soils, and helping mitigate climate change, and providing incomes, and providing economic opportunities,” Nierenberg says. “And urban agriculture in general has so much potential. But I think a lot of what it does is it creates community, because you have these gardens where community members can talk to each other, and trade seeds, and trade recipes, and you have a green space where kids can go and see food growing… and you create a sense of community, and I don’t know if these indoor farms can do the same thing.”
Vertical farms aren’t going to solve global hunger on their own, and, at least as they exist today, they come with some significant tradeoffs when it comes to community and the environment. That being said, it seems possible that someday they might play a valuable role in bringing fresh, affordable produce to urban communities. As Thomann puts it: “It is important to note that we’re not going to replace traditional farming, we are enhancing the farming model to be inclusive. Right now we have a very small market share of the overall agricultural category. I do see that increasing, but it takes time.”