financing the farm


Produce psyched about finance + encouraging you to tweet their hashtag || graphic by Lauren Mandel

Loquacious urban agriculture enthusiasts, like myself, revel in spreading the rooftop agriculture gospel.  I’ll happily talk your ear off about the countless benefits of rooftop farming, explain the technical intricacies of skyline farm design, and debate the most robust rooftop crops.  What I don’t often talk about, what most rooftop agriculture experts don’t often mention in depth, is finance, the elephant in the room.

Rooftop farmer Ben Flanner, working a farmers’ market in Brooklyn || photo by Jake Stein Greenberg

Earlier this week at Green Roofs for Healthy Cities‘ annual Grey to Green Conference in Toronto, I tackled this “elephant” head on with collaborators Ben Flanner (head farmer and president of Brooklyn Grange) and Mark Winterer (co-owner and director of operations at Recover Green Roofs, LLC).  Ben’s company owns and maintains two of the largest commercial rooftop row farms in the U.S. (totaling 2.5 acres) within the NYC region, and Mark’s company designs and builds green roofs in the Boston area, with a specialization in food roofs.  Together, we approached the topic of rooftop agriculture finance through the complimentary lenses of designer, farmer/business owner, and contractor.

Here are some of our main talking points, aimed at helping aspiring skyline farmers and entrepreneurs develop strong financing strategies.  One of the underlying messages throughout the talk was that while there are varied agricultural production methods and numerous financing strategies, no single approach is “right;” the approaches are simply different.

1| Designing with intent: The first step in realizing your vision for a rooftop farm is pinning down your primary goals.  Identifying your objectives and priorities early, while thinking about the big picture, will help you to stay focused and design with intent.  Simple questions to ask yourself are: who will grow the food?  Who will eat the food?  What yields are needed?  What scale of financing is possible?  These questions will help you select a production strategy.  Most commercial rooftop farms deploy some combination of raised beds, row farming, and/or greenhouse hydroponics.  You should consider how to best juggle construction costs with material integrity.  For example, untreated white pine is an inexpensive raised bed material, but it will degrade quickly and need to be replaced.  Cedar is much more expensive, but exhibits a much more long-lasting material integrity.  A greenhouse could last a lifetime.

2| Financing the farm: Most North American rooftop farms are financed using a hodgepodge of approaches.  These financing strategies often include some combination of loans, incentives (federal, state, or local), personal capitol, investor equity, parent company partnership, long-term purchasing agreement, and crowd-funding.  Fleshing out your multi-faceted strategy within your business plan is paramount.  During this process, allow your project goals, mission, and vision to drive your strategy.  In addition to making your business run more smoothly, a thoroughly developed financing strategy that acutely targets a goal will be more attractive to investors than a half-cooked plan.  Be specific, yet conservative, about cost and revenue projections.

High-initial investment production at Lufa Farms || photo by Lufa Farms

3| Profits and payback: Each agricultural production method mentioned above – raised beds, row farming, and greenhouse hydroponics – exhibits pros and cons.  The main financial consideration in selecting a method is whether you want a high cost, fast payback or low cost, slow payback approach.  Again, there is no “right” approach; there are simply different strokes for different folks.  When considering payback, research whether your city or state offers the following incentives for your rooftop farm: tax credits, tax abatements, subsidies, construction rebates, stormwater fee reductions, FAR bonuses, expedited permitting.  Also consider that full-coverage rooftop row farms will increase the life of your building’s waterproofing membrane by 2-3 times, which presents additional long-term savings.  A 1-2 storey building could additionally exhibit energy savings.

Low-initial investment method at Higher Ground Farm || photo by Maureen White, courtesy of Higher Ground Farm

4| Personnel dance card: Staffing should be organized to meet your farm’s needs.  Brooklyn Grange’s logistics, operations, and sales, for example, are run predominantly by the farm’s founding members.  Farms built by Recover Green Roofs, by contrast, are typically owned by a parent company (such as Whole Foods Market or Fenway Park) and farmed by a partner company, Green City Growers.  Another approach, deployed by Eagle Street Rooftop Farm, involves one head farmer aided by apprentices, interns (receiving college credit rather than a salary), and volunteers.  Lufa Farms – a leading Canadian greenhouse hydroponic company – has a staff of over 50, organized into sub-teams for management, production, outreach, etc.  Many of Lufa’s employees actually focus on developing technology, rather than on traditional production.

5| Innovative use of technology: One of the biggest differences between the sales approaches of rural and urban rooftop farms is the use of technology.  Most rooftop farms rely on websites, blogs, and social media (Facebook, Twitter, Instagram) to build their brand and their audience/customers.  One particularly innovative use of technology is Lufa Farm’s Online Marketplace, which allows the farm’s members to customize which farm goods they’d like each week. The goods are boxed and sent to local drop-off points around Montreal.

6| Replicating success: Your long-term financing strategy should consider one last key variable that many rooftop farming companies are already addressing: scale.  Many farms choose to gain rooftop acreage through networked rooftops.  If you want your rooftop farming company to be profitable, you’ll need to crunch some numbers to determine how big your raised beds, row farm, or greenhouse needs to be.  Keep in mind that launching multiple farms should be a phased approach, so keep calm and farm on!

EAT UP turns two!

Roof-to-Table Launch Event, 2013 || photo by Jane Winkel

It’s hard to believe, but this week EAT UP | The Inside Scoop on Rooftop Agriculture turns two!  My little bubelah is so grown up.  Since EAT UP’s publication by New Society Publishers in spring 2013, urban farmers and gardeners across the world have been able to get their paws on the first full-length book about rooftop food production.

Rooftop farmer Annie Novak at Eagle Street Rooftop Farm, 2010 || photo by Lauren Mandel

Some historians believe that rooftop agriculture dates back to 600 BCE Iraq, so how much could have possible changed in the past two years?  As it turns out, a groundswell has emerged.  When writing the first draft of EAT UP back in 2010, I posed the question of whether rooftop agriculture is viable.  At that time, little published information existed on the subject, aside from a handful of magazine articles, so I began conducting interviews with the budding industry’s leaders.  Annie Novak, Viraj PuriMohamed Hage, and Ben Flanner – all titans in the rooftop agriculture movement – were some of my first interviewees.  These urban farmers and CEOs revealed that the question of viability was moot; rooftop agriculture is real and it’s happening.

In response to the rapidly blossoming North American rooftop agriculture movement, drafts two through four of the book increasingly shifted focus from viability analysis to how-to.  Draft five (which was ultimately published as EAT UP) functions as a comprehensive resource featuring over 15 inspirational projects and offering readers the tools they need to pursue rooftop food production at three scales: gardening, farming, and industry.

During five short years of manuscript re-writes and post-publication, so many new rooftop farms and gardens have emerged that it’s become wonderfully impossible to keep track of each project.  The rooftop agriculture movement has organically reached it’s twining shoots around balconies and fire escapes, up walls, and across school and spanning warehouse roofs.  It’s everywhere.  In fact, a recent National Gardening Association report found a 17% increase in households with edible gardens during the past five years (from EAT UP’s first draft to now), which includes more than 13 million millennials.  The majority of millennials live in cities, so it’s conceivable that many of these gardens occupy urban settings.  Oh how the tide has changed!

Geographically speaking, where has the greatest increase in rooftop farms and gardens emerged?  As the birthplace of North America’s commercial rooftop agriculture industry and a city where space is at a premium, it’s no surprise that New York City makes the cut.  Chicago and Toronto’s green roof bylaws and favorable urban agriculture regulations similarly lend themselves to industry growth, so there’s no surprise there.

Ledge Kitchen & Drinks, 2012 || photo by Patrick Rogers Photography

And then there’s Boston.  Between you and me, Boston’s leadership in the rooftop agriculture movement comes as an utterly wonderful surprise, given the city’s cold climate and moderate density.  Many of the city’s high profile projects were designed and built by REcover Green Roofs, based in nearby Somerville, MA.  The company’s first food roof was built in 2010 atop a restaurant called Ledge Kitchen & Drinks, with later installations above the Boston Design Center and Whole Foods Market Lynnfield.  Just this week REcover Green Roofs’ newest food roof, Fenway Farm, began production at Boston’s own Major League Baseball stadium, Fenway Park.  Stay tuned for an EAT UP Blog post on this farm soon.

How will the rooftop agriculture movement mature by EAT UP’s next few birthdays?  That’s entirely up to you.  Climb up there and get started!

Philly’s tipping point

Philadelphia Mayor Michael Nutter at the 2015 GSK IMPACT Grant award ceremony || photo by Lauren Mandel

On March 19th ten players in Philadelphia’s urban farming community received a whopping $5 million grant award aimed at kickstarting healthy eating, exercise, and community building opportunities for local teens.  The IMPACT Grant, awarded by GlaxoSmithKline (GSK) and administered by The Philadelphia Foundation, provides local non-profits with financial resources to help disadvantaged youth live healthier lives and contribute to healthy communities.  The grant and GSK’s annual IMPACT Award targets communities surrounding GSK’s three US campuses, in Philadelphia, St. Louis, and Denver.

Top to bottom: Mayor Michael Nutter, Joie Kathos dancers, Philly public school student chef, Greener Partners || photos by Lauren Mandel

This year’s award winner, Get HYPE Philly, is a consortium of ten Philadelphia-based non-profits led by The Food Trust, a national leader in nutritious food access, founded in Philadelphia.  The partnership organizations project that their coordinated efforts will reach over 50,000 teens during the next three years through the following areas of focus:

“Eating healthy food is not a fad or a trend, it’s a lifestyle,” said Abdur Peay, a Thomas Mifflin School 7th grader, when speaking at the podium of the IMPACT Grant award ceremony.  “I’d like to bring HYPE to other cities and states, maybe go global.”  The youth’s words elicited cheering from the crowd of students, activists, executives, and media gathered at the Free Library of Philadelphia for the ceremony.  Philadelphia Mayor Michael Nutter followed Peay and fellow 7th grader Josiah Johnson with his own remarks, praising GSK’s investment in the health of young Philadelphians.  “Our administration has made this effort a priority in promoting healthy living,” said Nutter, before enthusiastically putting on a HYPE baseball cap.

Many of the Get HYPE Philly partnership organizations plan to expand their existing programming to target teens ages 12-18.  Liz Fitzgerald, culinary literacy specialist for the Free Library of Philadelphia, says the grant funding will enhance the library’s teen programming in the Culinary Literacy Center (which teaches literacy through cooking in the library’s new demonstration kitchen) and bring nutrition education to teens at library branches around the city.  Justin Trezza, executive director of Norris Square Neighborhood Project, is equally thrilled about the grant award and explains, “We’ve been waiting for something like this for a long time.”  Trezza’s organization serves mainly youth, 70% of which identify as Latino or biracial. “We don’t see gardening as purely producing food, but also as connecting people back to their cultures and heritage. With this [grant] we’re going to be hiring new staff, building a greenhouse, building a mobile farm stand to interact with out community members and offer them produce at a very, very affordable price.  We sell everything for a dollar.”

The $5 million IMPACT Grant award could be the tipping point in Philadelphia’s ongoing efforts to address food equity.  The award will be issued incrementally from 2015 through 2017, but Get HYPE Philly’s leaders plan to use the award as a springboard for future initiatives.  Yael Lehmann, executive director of The Food Trust, explained that, “We want to sustain this beyond the three-year period and that’s going to be an important part of our work that we’re going to start today, day one.”  Food access activists in Philadelphia and around the country will watch to see if this unique collaboration offers the muscle that’s needed to elicit lasting change and breed a new generation of leaders.

Seventh graders Abdur Peay and Josiah Johnson addressing the crowd || photo by Lauren Mandel

hungry for acreage


Gotham Greens co-founder + CEO Viraj Puri || video frame from Made in Brooklyn

We’ve been keeping an eye on Gotham Greens since the rooftop farming pioneer opened its first commercial greenhouse in 2010.  The Brooklyn-based company’s 15,000 square foot (0.3-acre) flagship farm, in Brooklyn’s Greenpoint neighborhood, yields 100 tons of leafy greens annually atop a warehouse building.  In 2013 Viraj Puri, the company’s savvy co-founder and CEO, struck a deal with Whole Foods Market to open a second rooftop greenhouse – 20,000 square feet (0.5-acre) – atop the supermarket’s Gowanus, Brooklyn store.  This year Gotham Greens plans to open another hydroponic rooftop farm in Jamaica, Queens, which will bring the company’s New York City acreage to 95,000 square feet (2.2-acres)!  Who would have guessed that this scale of urban cultivation was possible?

Rooftop farmers || video frame from Made In Brooklyn

“In cities we don’t have a lot of arable land, we don’t have a lot of fertile soil, but one vastly underutilized resource we do have is unused rooftop space,” said Puri in a November 2014 episode of TechCrunch TV’s Built in Brooklyn.  The CEO and his co-founders Eric Haley and Jennifer Nelkin Frymark have succeeded in meeting the local demand for fresh, responsibly-produced food using sustainable agriculture techniques.  Rainwater harvesting, re-circulating hydroponics, integrated pest management (IPM) and photovoltaics are just a few of the tools the team deploys to bring viable urban agriculture to New York City.

Rooftop basil sold downstairs at Whole Foods Market Gowanus || video frame from Made In Brooklyn

Which other cities contain building stock large and strong enough to support commercial-scale hydroponic greenhouses?  Many older cities like Philadelphia, Pittsburgh, San Francisco and of course Chicago (which is slated to receive a 75,000 square foot Gotham Greens rooftop farm for a new Method Products factory) fit the bill.  These are cities in which retrofit projects are likely to continue appearing.  In terms of new construction, it’s likely that companies beyond Whole Foods Market and Method Products will consider integrating rooftop farms into designs for future buildings.  Row farms may be considered for these new construction projects, but if high, predictable year-round yields are a priority, it’s likely that hydroponic greenhouses will be utilized.

Let’s keep an eye on the sky in our own cities to see what skyline infrastructure blossoms in the seasons to come.  And remember, if you see rooftop produce at a market near you, be sure to support your local skyline farmers by buying their greens!

ruminating on rain barrels

Herb pruning at Eagle Street Rooftop Farm || photo by Lauren Mandel

Winter is the perfect time for gardeners and farmers to rest, plan for spring planting, and investigate big questions that sprouted during the past growing season.  My big question this winter: Is it safe to water edibles with roof runoff?

As a green roof designer I regularly work with architects and building owners to select waterproofing membranes for large green roof projects (generally 5,000 square feet to several acres in size).  We discuss the pros and cons of each waterproofing material, such as cost, ease of install, and compatibility with leak detection technology.  What we do not discuss is whether it’s safe for water flowing over the waterproofing to be collected for crop irrigation.  Why don’t we discuss this?  Because until recently the simple answer was, “not a chance!”  Waterproofing (like PVC, TPO, hot liquid-applied rubberized asphalt, and even asphalt shingles) contains toxic elements and compounds that leach into runoff.  Watering crops with this contaminated water douses your food with toxins like chromium, copper, zinc, cadmium, and lead.  Pathogens like coliform bacteria and Escherichia coli can also enter the water from rooftop bird droppings.

Home rooftop gardening in West Philadelphia || photo by Lauren Mandel

For decades, though, homeowners have directed runoff from roofs into rain barrels to irrigate ornamental and edible plants.  In cities, rain barrels are often located on balconies (for watering rooftop edibles), back patios, or near front stoops.  Rain events fill the barrels, then water is released through a spigot or into a gravity-fed hose or drip irrigation system.  Have these gardeners been poisoning their families?

New information suggests that using roof runoff to irrigate edibles may be A-OK, with a few caveats.  A January 7 article by Lisa Stiffler in Sightline Daily – a digital publication by Seattle sustainability think tank, Sightline Institute – summarizes the findings of three recent scientific studies that investigated this very issue.  The first is a Journal of the NACAA article by Haberland, Bakacs, and Yergeau (2013) that monitored toxins (lead, zinc, coliform bacteria, E. coli, and polycyclic aromatic hydrocarbons) in six urban and six suburban rain barrels, supplied by runoff from asphalt shingle roofs in New Jersey.  The study found that, left untreated, the water contained levels of E. coli exceeding that recommended for crop irrigation by the U.S. Food and Drug Administration.  The second highlighted study is a Washington State Department of Ecology publication by Winters, McCall, and Kingfisher (2014), which studied toxin concentrations in runoff over time as waterproofing materials whether.  Researchers monitored toxin levels (arsenic, cadmium, copper, lead, zinc, and organic compounds) in runoff from 18 constructed roofing panels during an 11 month period.  The study finds that:

Harvesting home rooftop herbs || photo by Lauren Mandel

Across the 20 rain events, [Washington State Department of Ecology] found that asphalt shingle, built-up, modified-built-up, TPO without brominated flame retardant, concrete tile, and untreated wood shingle roofing materials did not release elevated levels of the metals or organic compounds evaluated in runoff.

The study includes several recommendations for assessing the roof condition and its runoff, which are relevant to rain barrel use.  The third study is a PLOS One article by Tom, Fletcher, and McCarthy (2014) tested heavy metal uptake by French bean (Phaseolus vulgaris), kale (Brassica oleracea var. acephala), and beetroot (Beta vulgaris) in Melbourne, Australia.  Researchers watered the crops for 11 weeks with synthetic stormwater then tested for elements (cadmium, chromium, lead, copper, and zinc).  The study found that lead uptake was most significant, but some crop varieties contained higher concentrations than others.  For example, kale and beet roots contained lower metal concentrations than French beans and beat greens.  The study recommends being selective about crop types and turning soil regularly when watering crops with roof runoff.

Suggested Guidelines when Watering Crops with Roof Runoff*

1| Be selective about the roofing material: Do not water crops with runoff from treated wood-shake roofs; roofs treated with chemicals to kill moss, algae, or rot; roofs with zinc strips; copper roofs; or roofs with copper gutters.

2| Don’t collect the “first flush”: Divert runoff from the first few heavy storms after a dry spell away from crops, into the storm drain.

3| Add bleach: Rutgers researchers recommend adding approximately one ounce of household unscented chlorine bleach to 55 gallons of water to kill the bacteria, then waiting 24 hours before watering.

4| Water the soil, not the food: Some soil microorganisms are able to break down certain toxins.  Allowing these microorganisms to come in contact with the water before the plants do may decrease soil contamination.

5| Wash produce: Washing home-grown fruits, veggies, and herbs grown with harvested rainwater can help remove surface contaminants.

6| Clean the rain barrel: Rinsing the rain barrel on occasion can help remove particulate and bacteria.  Some recommendations include mixing 1/8-cup chlorine bleach with five gallons water, then rinsing the barrel clean with municipal water.

* These guidelines are included in the Sightline Daily article referenced above, and are not expressly recommended by EAT UP, LLC.  It is each gardener and farmer’s sole responsibility to decide whether or not to water edible crops with rooftop runoff.  Local and national guidelines should always be adhered to for the protection of human health.

jet setters

Photo by Lauren Mandel

Like most of us, you probably spent a fair slice of this holiday season in transit, traveling by car, bus, train, or perhaps even by airplane.  With time-sucking security check points and flight delays, airline travel certainly isn’t as glamorous as it once was, but one stressor may be on the up-and-up: the food.

On Monday, The New York Times reported on a rising trend in farm-fresh food within American airports in an article aptly named “Airports Modernize Dining Options With Farm-to-Terminal Fare.”  Journalist Matt Krupnick reminds us of the fast food and stale, prepackaged sandwiches that most of us have regrettably grown accustomed to while traveling by plane or wading through layovers.  According to Krupnick, though, “[t]he farm-to-table movement has come to airports across the country, bringing fresh, local produce, meat and other goods to restaurants led by well-known chefs and shops with local culinary specialties.”  My own 2014 travel experiences corroborate Krupnick’s assertion of star chefs bringing local food to airports.  For example, the Philadelphia International Airport now houses celebrity chef Jose Garces’ restaurant called Local (Terminal F), and Chicago O’Hare International Airport similarly boasts chef Rick Bayless’ Tortas Frontera (Terminals 1, 3 and 5).  Krupnick adds that restaurants operated by OTG Management at Newark Liberty International Airport’s newly renovated Terminal C will be required to buy local three times per week from spring through fall.

How local can airport food be grown?  Most farm-fresh ingredients are trucked in from within 50 miles or coordinated through a third party purveyor, such as FarmLogix, but in 2011 Chicago O’Hare International Airport became one of the first to grow food directly on site.  The airport’s indoor Aeroponic Garden, located in the Rotunda Building within Terminal 3, provides leafy greens and herbs year-round to diners in more than four airport restaurants, including Tortas Frontera and Wolfgang Puck.  JetBlue is considering following O’Hare’s lead by growing potatoes or other crops at John F. Kennedy International Airport.

Chicago O’Hare International Airport’s aeroponic garden || photo by Chicago Department of Aviation

Top: Hydroponic rooftop greenhouse in Gowanas, NY / Bottom: Los Angeles International Airport || photos by Lauren Mandel

But why grow indoors or on the ground rather than cultivating the endless acres of airport rooftops?  Rooftop agriculture at airports makes good sense for several reasons that we should ruminate on in 2015:

1| Reducing food miles: Shipping food can be costly and contribute to traffic congestion, pollution, and excess packaging, while resulting in diminished flavor and nutrient levels in many fruits and vegetables.  The closer that crops are produced to the end user (i.e. restaurant or vendor), the more flavorful and sustainable the result is likely to be.

2| Creating jobs: Airports are often one of the largest employers in a city.  Adding on-site food production would result in skilled and un-skilled job creation.

3| Ensuring food safety: Aircraft pollution poses a serious risk to food grown in fields underneath jet streams.  Growing food hydroponically in greenhouses above buildings with large footprints (such as those at airports) protects crops from toxic particulate.  This type of year-round production produces high, predictable yields.

Toronto-style thin farming

Ryerson University’s George Vari Engineering and Computing Centre rooftop farm || photo by Vincent Javet, Green Roofs for Healthy Cities

As ornamental green roofs increasingly coat our skylines, some urbanites have begun re-purposing older vegetated rooftops for agriculture.  One example, north of the border in Toronto, is Ryerson University’s George Vari Engineering and Computing Centre, constructed in 2004.  The building supports a 6-inch thick extensive green roof that was intended to moderate indoor temperature, manage stormwater, and give students a living research platform.  A monoculture of widely spaced daylilies (Hemerocallis spp.) initially inhabited the green roof, which was quickly colonized by more than 30 volunteer plant species, even trees!


Four step weed-to-farm conversion || photos by Vincent Javet, Green Roofs for Healthy Cities

Seven years after construction, the university’s edible gardening group, Rye’s HomeGrown, began ruminating on whether the green roof should be re-purposed for agriculture.  Two years later, in 2013, students, faculty, and community members finally rolled up their sleeves to replace the roof’s weeds with edibles in a small test plot.

Volunteers began by cutting back the weeds and leaving the clippings in place.  They then laid tarps over top of the plot for several weeks – a common garden preparation technique – in order to kill the remaining root systems and begin to decompose the underlying plant material.  Next, the volunteers removed the tarps, spread two inches of compost over the plot, and installed a surface-drip irrigation system.  The first growing season produced an impressive 500 pounds of nightshades, cucurbits (squash, melons, etc.), leafy greens, and herbs.

Once the pilot project proved successful, Rye’s HomeGrown worked closely with the university’s Campus Facilities and Sustainability to convert the remaining green roof area, 10,000 square feet (almost 1/4 acre), into a rooftop farm.  The expansion occurred in early summer 2014, thanks to the help of 17 Farm the Roof Program participants who each volunteered five hours per week.  According to the Rye’s HomeGrown website, the full-scale farm is intended to produce food and, “provide growing knowledge, education and hands-on opportunities for interested participants.”  Rye’s HomeGrown’s early estimates predicted that the expanded farm would yield 7,500 pounds of vegetables and herbs per year.  The produce is distributed to the university’s cafeteria, a local farmers’ market, and community supported agriculture (CSA) members.

Will other Torontonians follow suit and convert their extensive green roofs into edible roofscapes?  The odds look good!  Toronto’s skyline boasts an abundance of green thanks to the city’s 2009 Green Roof Bylaw, which made Toronto the first North American city to require green roofs on new construction.  The bylaw specifies that all new buildings larger than 2,000 square meters (21,500 square feet) contain at least 20%-60% green roof coverage, depending on project size.  Residential buildings less than six stories are exempt.  With so many new commercial, mixed-use, and multi-family residential buildings, the opportunity to farm the skyline is continually growing.

Did you enjoy reading about this topic?  You may also like these additional articles on thin farming by EAT UP author Lauren Mandel: “Roof-to-Table” (Landscape Architecture Magazine, 2014), “Thin Farming” (Urban Farm Magazine, 2014), and “Skyline Vegetable Convention” (EAT UP Blog, 2013).



a salute to urban fish


Seattle urban fish || photo by Lauren Mandel

Some days you can eat leafy greens until the cows come home without ever feeling full.  The missing link?  Protein.  While chickens and livestock often play a key role in addressing this classic omnivorous hunger, raising these animals in cities can be challenging due to spacial needs and local health code regulations.  What’s an urban locavore to do?


Switzerland’s LokDepot rooftop farm || rendering by Urban Farmers

Enter the urban fish.  Raising fish in cities, for food, has become increasingly popular during the past 5-10 years as urban agriculturalists have grown curious about aquaponics.  In this agricultural practice, plants and aquatic animals are raised symbiotically in a closed-loop environment.  Vegetables and herbs are grown hydroponically (often on floating rafts) while fish or other sea creatures occupy the water that fuels the hydroponic system.  The animal waste (fecal matter, excess food, etc.) is used as a nutrient source for the food crops, and in exchange the plants filter the water for the fish.  The clean water is then pumped back into the hydroponic system and the cycle continues.  Talapia is the fish of choice for many aquaponic farmers due to the species’ fast growth rate, robustness in poor water conditions, flavor, and of course, protein content.

Aquaponics is most often pursued on the ground or in basements, as water weighs around 62.5 pounds per square foot – a heavy load for most roofs!  But in January 2012, the world’s first commercial aquaponics rooftop farm opened for production in Basel, Switzerland, near the borders of France and Germany.

Urban Farmers, a Swiss company that builds and operates rooftop farms, constructed the $900,000 rooftop aquaponics greenhouse, known as UF001 LokDepot.  The 2,700 square foot farm functions as Urban Farmers’ rooftop pilot project and is designed to produce 5 tons of vegetables and over 1,800 pounds of fish per year.  According to Ranka Junge, an aquaponics researcher and professor at Zhaw Zurich University, “In Basel there is 2,000,000m² of vacant rooftop space. If 5% of this rooftop space were used for aquaponics, that is 100,000m², which could feed 34,000 people or contribute 8-20% of the fresh fish and vegetable consumption in Basel.”  UF001 LokDepot’s hyper-local crops are currently sold to some of Basel’s top restaurants.


Operational modular aquaponics greenhouse || photo by Urban Farmers

Urban Farmers built the UF001 LokDepot farm from prefabricated, modular greenhouse units.  The units were lifted to the roof by crane and secured in place, then affixed with interior infrastructure typical of hydroponic facilities, such as grow lights and retractable shade cloth.  The modular nature of Urban Farmers’ design suggests that the greenhouse units could be installed to create semi-custom aquaponics farms on many roofs around Switzerland and beyond.  Urban Farmers has also developed modified agricultural shipping containers that the company has installed in tandem with their greenhouse projects.

The next time you stare into a fish tank at a sushi bar or doctor’s office, be sure to take a moment to appreciate the urban fish in our lives and how they can help feed the city.