Our current agricultural system can produce plenty of food. It’s just not very good at distributing it.

Food deserts have appeared in our cities.

People living in poor neighborhoods have no conveniently located stores where they can buy fresh produce.

Community gardens and urban farming can help.

We can understand gardens as providing food for the people who tend them. Farms grow food to sell (or perhaps donate) to others.

Urban farms, so far, can’t grow grains or operate large-scale orchards. Raising some animals works well in urban agriculture: poultry, fish, rabbits, or bees. Rural farms must still handle cattle and dairy products

Kinds of urban farming

Urban farms must produce large quantities of food in minimal space.

They have developed a variety of techniques to fit a variety of locations.

Some urban farms grow crops in formerly vacant lots or on rooftops.

The plants may grow in garden plots, in raised beds, or in various kinds of containers. They can grow outdoors or in a greenhouse.

Other projects take over abandoned buildings and grow plants without soil. Three basic methods of soil-less growing exist:

• Hydroponic gardening pumps nutrient-rich water to the plant roots. The method works with or without some kind of solid medium like coconut husk or growrock.
• Aquaponics is similar, except that the growing system includes fish, which in some systems, can be grown as food. Waste from the fish nourishes the plants, which filter the water and keep it clean enough for the fish.
• Aeroponics grow crops in air. Their roots grow neither in soil nor water. Instead, machinery applies nutrient-rich water to the roots as a mist.

Soil-less growing works very well in small spaces, either indoors or out. It uses modules that can be stacked one on top of another for vertical farming. And soil-less methods use water more efficiently than does soil.

It works less well with large containers. Urban farmers must monitor the systems carefully. Otherwise the plants can dry out quickly. Many people claim that plants grown in soil taste better than those grown without soil.

Vertical farming

Vertical farming stacks layers of trays. In principle, vertical farms can stack containers of soil in such a way that they receive natural sunlight.

Mostly, however, modern vertical farms use one of the soil-less methods indoors and grow the plants with artificial light.

Proponents claim that vertical farming will revolutionize agriculture by growing food close to population centers without pesticides or fertilizer.

In principle, it grows more food in less space and has little if any negative effects on the environment.

Since vertical farms depend on artificial light and machinery to pump and control water, they use a lot of energy. Supporters claim renewable energy can provide it..

Critics point out that solar and wind power convert energy from the sun to electricity. Electricity operats LED lights. Then the plants convert the light to food energy.

Every point of conversion loses energy. The output in food energy must necessarily be less than the input in solar or wind power. The system also requires heavy investment in infrastructure.

All so plants can do in an artificial environment what they do at so much less cost in nature.

And soil-less agriculture can’t grow grains or root vegetables.

Examples of urban farming

Here are a few urban agriculture projects from all over the world.

They use different farming techniques and have different goals.

But they all provide food to a specific local area.

Detroit, Michigan

Food Field, in Detroit, Michigan, converted the site of an old elementary school to a farm. Operated by Peck Produce, LLC, it provides both food and economic opportunities to the neighborhood through a Community-Supported Agriculture (CSA) program.

That is, people in the community share the farms financial risks in return for receiving food from it. The farm also sells to local restaurants. It has recently added an aquaponics system so it can raise fish in addition to eggs from its chickens and ducks.

Rising Pheasant Farms in Detroit comprises a greenhouse and a one-fifth acre plot of ground. Owner Carolyn Leadley sells sprouts, shoots, and microgreens at a market on the east side of town and to restaurants.

Leadly says that the vegetables from her outdoor plot look good on the farm stand, but can’t bring in enough money for the farm to stay in business. The greenhouse grows shoots, sprouts, and other microgreens she can sell year-round at a good price.

These are just two of more than 1,300 commercial farms, community gardens, and school gardens in Detroit that, in 2014, grew more than 400,000 pounds of produce.

New York

New York City has begun to grow rooftop gardens on its buildings. With more than 38,000 acres of rooftop space suitable for farming, New York has become a leader in urban agriculture. The Five Borough Farm is but one organization that helps make it so.

Gotham Greens operates two hydroponic rooftop greenhouses. After Hurricane Sandy (2012) and the blizzards of the following winter, it provided the only produce available in many New York groceries.

Newark, New Jersey

AeroFarms in Newark, New Jersey repurposed an abandoned steel mill to create a vertical farm.

They say it will produce two million pounds of leafy greens every year using aeroponics.

Stacks of planters with no soil rely on artificial light and very moist air. The company spent $30 million on the project.

Bryan, Texas

The Distributed Urban Farming Initiative has started to turn vacant lots into farmland. It grows vegetables in raised bed and pallet gardens. Besides selling produce to restaurants, it conducts field trips and other events on its lots for public education.

London, England

An eco-social design company called Something & Son opened FARM:Shop in 2011. It installed an aquaponics system in an old storefront. And on the roof, it operates a chicken coop.

Next for Something & Son: a 3,000 square-meter rooftop farm called FARM:London. It aims not only to grow food, but demonstrate to residents of one of the largest cities in the world that growing food does not require acres of space.

Singapore

Singapore must import nearly all its food. A vertical farming project called Sky Greens aims to increase local production of vegetables. It uses a hydraulic water system to reduce energy use.

Located in a three-story greenhouse, it can grow vegetables all year. It sells its produce through grocery stores.

Economics of urban farms

I have to wonder about the cost of building AeroFarms.

Can such expensive projects recoup the investment and start to make a sustainable profit?

Many urban farms operate on very small margins, in part because they invest heavily in community education.

Elizabeth Bee Ayer, owner of Youth Farm in Brooklyn, analyzed the process of growing beets. She noted all the necessary hand movements and the time it took to wash them and prepare them for sale.

The farm sold them for $2.50 per bunch of four and lost 12¢ for every beet. Raising the price would price them out of the market for its customers. Instead, Ayer raised the price on a cheap and popular herb to subsidize the beets.

So far urban farms can’t produce enough food to supply large buyers like grocery stores, schools, or hospitals. Scaling them up will require aggregators to market to them effectively.

It will also require a adjustments such as making optimum use of space and biointensive methods of increasing yield and efficiency.

We also need a lot more urban farms and community gardens. So far, we don’t have enough of either  to solve the problem of food deserts.

Sources:
3 basic soilless growing methods for urban farming beginners / Urban Vine
Five examples of successful urban agriculture done differently around the world / Emily Salshutz, Food Tank. October 14, 2013
The future of urban farming / Shea Schwesinger, Museum of the City [Link no longer works.]
Urban farming is booming, but what does it really yield? / Elizabeth Royte, Ensia. April 27, 2015
Vertical farms: wrong on so many levels / Lloyd Alter, Treehugger. February 26, 2016
World’s largest vertical farm grows without soil, sunlight or water in Newark / Malavika Vyawahare, The Guardian, US Edition. August 14, 2016

Photo credits:
Urban farming in Copenhagen. Some rights reserved by Mark Stevens
Green roof. Public domain from Wikimedia Commons
AeroFarms. U.S. State Department. Public domain
Vertical farming. Public domain from Wikimedia Commons
Aquaponic farm. Public domain from Wikimedia Commons
Hayes Valley Farm. Public domain from Wikimedia Commons.