No, Vertical Farms Won’t Feed the World
Lettuce grown in my garden. Photograph © 2016 Jonathan Foley
August 1, 2018
While they are well-intentioned, new indoor “farms” won’t help feed the world or reduce the environmental impacts of agriculture. We would be better to focus our efforts elsewhere.
We’re beginning to see a new fad in agriculture — so-called “vertical farms” that grow food indoors with energy-intensive, artificial life support systems.
In the last few years, a number of tech companies have designed “farms” that utilize artificial lights, heaters, water pumps, and computer controls to grow crops inside. These systems glow with a fantastic magenta light — from LEDs that are specially tuned to provide optimal light for photosynthesis — often with stacked trays of plants, one on top of the other. Some of this technology is new, especially the LEDs, although pot growers have used tools like this for years.
Some of the more notable efforts to build indoor “farms” include Freight Farms in Boston. And there is a group at MIT that is trying to create new high-tech platforms for growing food inside, including “food computers”. These folks are very smart and have done a lot to perfect the technology.
At first blush, these “farms” sound great. Why not completely eliminate food miles, and grow food right next to restaurants, cafeterias, or supermarkets? And why not grow crops inside closed systems, where water can be recycled, and pests can (in theory) be managed without chemicals.
It sounds great, doesn’t it? But there are many challenges.
First, Vertical Farms Cost a Fortune
But there are costs to these farms. Huge costs.
First, these systems are really expensive to build. The shipping container systems developed by Freight Farms, for example, cost between $82,000 and $85,000 per container — an astonishing sum for a box that just grows greens and herbs. Just one container costs as much as 10 entire acres of prime American farmland — which is a far better investment, both in terms of food production and future economic value. Just remember: farmland has the benefit of generally appreciating in value over time, whereas a big metal box is likely to only decrease in value.
Second, food produced this way is very expensive. For example, the Wall Street Journal reports that mini-lettuces grown by Green Line Growers costs more than twice as much as organic lettuce available in most stores. And this is typical for other indoor growers around the country: it’s very, very expensive, even compared to organic food. Instead of making food more available, especially to poorer families on limited budgets, these indoor crops are only available to the affluent. It might be fine for gourmet lettuce, or fancy greens for expensive restaurants, but regular folks may find it out of reach.
Finally, indoor farms use a lot of energy and materials to operate. The container farms from Freight Farms, for example, use about 80 kilowatt-hours of electricity a day to power the lights and pumps. That’s nearly 2–3 times as much electricity as a typical (and still very inefficient) American home, or about 8 times the electricity used by an average San Francisco apartment. And on the average American electrical grid, this translates to emitting 44,000 pounds of CO2 per container per year, from electricity alone, not counting any additional heating costs. This is vastly more than the emissions it would take to ship the food from someplace else.
And none of it is necessary.
But, Wait, Can’t Indoor Farms Use Renewable Energy?
Proponents of indoor techno-farms often say that they can offset the enormous sums of electricity they use, by powering them with renewable energy —, especially solar panels — to make the whole thing carbon neutral.
But just stop and think about this for a second.
These indoor “farms” would use solar panels to harvest naturally occurring sunlight, and convert it into electricity so that they can power…artificial sunlight? In other words, they’re trying to use the sun to replace the sun.
But we don’t need to replace the sun. Of all of the things we should worry about in agriculture, the availability of free sunlight is not one of them. Any system that seeks to replace the sun to grow food is probably a bad idea.
Besides, “Food Miles” Aren’t a Big Climate Problem
Sometimes we hear that vertical farms help the environment by reducing “food miles” — the distance food items travel from farm to table — and thereby reduce fuel consumption and greenhouse gas emissions.
This sounds logical, but it turns out to be a red herring.
Strange as it might seem, local food typically uses about the same amount of energy — per pound — to transport as food grown far away. Why? Short answer: volume and method of transport. A larger food operator can ship food more efficiently — even if it travels longer distances — because of the gigantic volumes they work in. Plus, ships, trains, and even large trucks driving on Interstate highways use less fuel, per pound per mile, than small trucks driving around town.
Plus it turns out that “food miles” aren’t a very big source of CO2 emissions anyway, whether they’re local or not. In fact, they pale in comparison to emissions from deforestation, methane from cattle and rice fields, and nitrous oxide from over-fertilized fields. And local food systems — especially organic farms that use fewer fertilizers, and grass-fed beef that sequesters carbon in the soil — can reduce these more critical emissions. At the end of the day, local food systems are generally better for the environment, including greenhouse gas emissions. Just don’t worry about emissions from food miles too much.
And These Vertical “Farms” Can’t Grow Much
A further problem with indoor farms is that a lot of crops could never develop properly in these artificial conditions. While LED lights provide the light needed for photosynthesis to occur, they don’t provide the proper mix of light and heat to trigger plant development stages — like those that tell plants when to put on fruit or seed. Moreover, a lot of crops need a bit of wind to develop tall, strong stalks, needed later when they are carrying heavy loads before harvest. As a result, indoor farms are severely limited and have a hard time growing things besides simple greens.
Indoor farms might be able to provide some garnish and salads to the world but forget about them as a means of growing much other food.
A Better Way?
I’m not the only critic of indoor, high-tech, energy-intensive agriculture. Other authors are starting to point out the problems with these systems too (read very good critiques here, here, here, and here).
While I appreciate the enthusiasm and innovation put into developing indoor farms, I think these efforts are, at the end of the day, counterproductive.
Instead, I think we should use the same investment of dollars, incredible technology, and amazing brains to solve other agricultural problems — like developing new methods for drip irrigation, better grazing systems that lock up soil carbon, and ways of recycling on-farm nutrients. Organic farming and high-precision agriculture are doing promising things, and need more help. We also need innovation and capital to help other parts of the food system, especially in tackling food waste and getting people to shift their diets towards more sustainable directions.
An interconnected network of good farms —real farms that provide nutritious food, with social and environmental benefits to their communities — is the kind of innovation we really need.
Dr. Jonathan Foley (@GlobalEcoGuy) is a global environmental scientist, sustainability advisor, author, and public speaker. These views are his own.
© 2018 by Jonathan Foley. All rights reserved.
NOTE: parts of this piece were adapted from an earlier blog article of mine called “Local Food is Great, But Can It Go Too Far?”