EAT UPToronto-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.
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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.
putting your money where the mouths are
Lufa Farms founder + CEO Mohamed Hage || photo by Lufa Farms
“Imagine cities that feed their own inhabitants. Imagine communities that are connected by farms. Imagine knowing your farmer and knowing your food.” This is the vision of Mohamed Hage, founder and CEO of the Montreal-based rooftop farming company Lufa Farms, articulated during his 2012 TEDx Talk. Hage is a pioneer in the rooftop farming industry, pushing the limits of skyline hydroponics to cultivate as much food as possible directly in the heart of cities. What’s his secret? Unparalleled business sense.
0.7-acre Ahuntsic location || photo by Lufa Farms
Lufa Farms grows roof-fresh produce in two locations: a 32,000 square foot (0.7 acre) greenhouse in Montreal’s Ahuntsic neighborhood and a 43,000 (1.0 acre) greenhouse in neighboring Laval, Quebec. The farms opened for business in 2011 and 2013, respectively, after several years of planning and development. Hage partnered with several hotshots to create the company’s leadership team. Each brings a unique suite of skills to the table, thereby fostering a robust group of leaders. Lauren Rathmell, a trained biochemist, serves as Lufa Farm’s greenhouse director; Yahya Badran, owner of a construction company, is the director of engineering; and Kurt Lynn, a local entrepreneur, serves as the company’s advisor. Together with Hage the team has successfully grown Lufa Farms to feed approximately 6,500 Québécois year-round through a distribution model akin to a CSA (community supported agriculture) crossed with online shopping. The business has been so successful, in fact, that Hage is evaluating new farm locations within Quebec, Ontario and the northeastern U.S.
Financing a commercial-scale, hydroponic rooftop farm is not cheap. Ventures such as Hage’s may cost upwards of $70 per square foot to construct, putting the price tag for one farm in the millions. Investing in this scale of business means that for starers, each farm must be located near potential customers (thus is born the pun, “putting your money where the mouths are”). After selecting these hyper-local locations, Lufa Farms takes the next step by securing subscribers, or customers who buy 12-weeks of farm-fresh groceries delivered weekly to drop-off points. Operating under a subscription model is a slick business move on Hage’s part; one that provides a more accurate prediction of revenue compared to a farm that relies upon single purchases and is subject to market price fluctuations.
Hydroponic tomato farming || photo by Lufa Farms
Another key to Lufa Farms’ success is the company’s effective use of technology. From programming each greenhouse’s micro-climates to innovating iPad apps for the farmers and creating an online Marketplace for customers, Lufa Farms is dialed in to the tech world. This successful integration comes as no surprise, as Hage, is a self-described “technology geek” according to a 2013 interview. Before delving into the creation of Lufa Farms, Hage founded Cypra Media, which is now a major email service provider in Canada.
Lufa Farms’ success serves as a shining example of healthy farming practices combined with business know-how. Lufa Farms also reminds us that our own farming businesses cannot be sustainable for the long-term without satisfying the triple bottom line: people, planet and profit.
rooftop rice paddy
Fertilizing rooftop rice in Liuzhou, China || photo by Xinhua
Two hectares of rooftop in South Central China’s Guangxi Zhuang Autonomous Region stand a cut above the rest. The Liuzhou Chenfeng Brewing Factory, founded in 1954, supports one of China’s only rooftop rice paddies. Tan Zhaohan, the factory’s head rice planter, reported to David Cao of Bejing Impact that the roofs were first planted in 2010. Rice, lotus and vegetables flourish on the roof while other crops are grown on the property at ground-level.
Vegetable, lotus and rice crops flourish on the brewery roofs || photo by Xinhua
According to Zhaohan, the brewery’s owner developed this agricultural rooftop vision and took the necessary steps to enhance each roof area’s waterproofing membrane. This process likely involved either patching and testing the existing membrane for water tightness (i.e. leaks) or applying a new membrane altogether. Water pumped from underground is ponded on the roof thanks to six drains on each roof with adjustable collars. The collars allow workers to adjust the rice paddy’s water level depending on crop needs.
Ponding water on rooftops is a common practice today in cities like New York, where local stormwater regulations incentivize a reduction in peak delay. Allow me to explain. During a rain event or snow melt event, water hits roofs, streets and other impervious surfaces and rushes to the storm sewer, often overloading the system. When we’re able to delay the rate at which water flows to the sewer after such an event, that’s called reducing the peak delay. On rooftops this delay can be achieved through green infrastructure such as green roofs, or by ponding water for 24 hours within a blue roof. Another type of rooftop ponding, common in Germany, involves ponding 1″-2″ of water at the base of a green roof to provide base-level irrigation water to the plants. A third example of rooftop ponding has been articulated by historian Geoff Wilson, who believes that the Hanging Gardens of Babylon (in present-day Iraq) may have supported rooftop aquaculture, or fish farming, for the building’s residents.
Skyline farmers in Liuzhou, China || photo by Xinhua
While rooftop ponding is clearly nothing new, its use for growing commercial grain and vegetables is astounding. I must admit that I’ve been asked about the feasibility of growing rice on rooftops several times throughout the years, and have brushed off the question as an impossibility each time. After recently learning of the Liuzhou Chenfeng Brewing Factory roof, though, I am shamed! Cultivating rooftop rice is indeed feasible given proper growing and architectural conditions.
Why build a rooftop rice paddy, you ask? The benefits are twofold. First, the rooftop farm provides fresh, in-house produce to the brewery below for beer making, wine making and other uses. This on-site production may result in monetary savings to the brewery because the business would need to buy fewer ingredients. Given the size of the roof areas, though, it’s likely that most ingredients are still purchased from producers or suppliers.
Cultivating rooftop vegetables || photo by Xinhua
Secondly, the brewery’s manager, Liu Xinsheng, reported to Bejing Impact that the rooftop farm helps to moderate the buildings’ indoor temperature, thereby saving the company money on utility bills. This makes sense, because water holds heat longer than a bare membrane roof. As outdoor temperatures fluctuate, the water within Liuzhou Chenfeng Brewing Factory’s rice paddies remains relatively constant. During the heat of day the paddies reduce the need for indoor air conditioning. Additionally, the brewery is only one story tall, which furthers the ability of the rooftop farm to keep the building cool. Temperature control via green roofs and blue roofs is a function of the area of the roof relative to the volume of the building, which means that low (1-2 story) buildings reap the largest temperature benefits.
The potential for cultivating rooftops for culturally-relevant crops is expanding, thanks to rooftop farms such as that atop the Liuzhou Chenfeng Brewing Factory. Let’s wait and see what impossibilities become possible around the world as creative thinkers transform their rooftop acreage.
grey to green
Brooklyn Grange rooftop farm || photo by Allen Ying
Think green infrastructure is sexy? Don’t hold yourself back from nerding out with others, like yourself, who blush at the thought of rooftop farming, green walls, biofilters and living machines. On August 25 and 26, Green Roofs for Healthy Cities – the North American green roof and green wall trade association – welcomes an international crowd to its annual Grey to Green Conference in Toronto.
This year’s conference focuses on the economics of green infrastructure and designing for health, two burgeoning areas of thought within the design and city planning realms. Registering for the conference will expose you to more than 75 speakers, local project tours, networking opportunities, continuing education credits (from OAA, LA CES, USGBC/GBCI, AIA CES, BOMI, APLD and RCI), and training courses.
One of the most informative courses may just be “Introduction to Rooftop Urban Agriculture,” taught by yours truly on August 26 from 8:30-noon. This Green Roofs for Healthy Cities training course is generally taught by rooftop farming superstar Ben Flanner, of Brooklyn Grange. I am delighted to pinch hit for Ben while offering the designer’s perspective to rooftop agriculture. I’ll also offer anecdotes and lessons learned from my interviews with rooftop farmers and gardeners throughout North America.
Philadelphia book signing || photo by Jane Winkel
On the conference’s opening day, August 25, be sure not to miss the Grey to Green book signing from 11:45-1:45. You’ll get to chat with me and other authors one-on-one about your own project. Maybe you’ll even buy a copy of EAT UP and get it signed and personalized!
The conference’s keynote talks should similarly not be missed. The talented group of keynote speakers includes:
– John Howard, MD, Chair of the Canadian Association of Physicians for the Environment: “Green Infrastructure and Prevention Health Care”
– Kathleen Wolf, Ph.D., Social science researcher at the University of Washington: “The Economic Value of the Human Health Benefits of Urban Green Infrastructure: A Lifecycle Approach”
– Bill Browning, a global expert in biophilic design and principal at the environmental consulting firm Terrapin Bright Green: “The Emerging Science, Health and Economic Benefits of Designing our Buildings with Nature”
– Craig Applegath, PPOAA, AAA, MAIBC, NSAA, FRAIC, LEED® AP, Architect and principal at DIALOG: “Regeneration, Resilience and Symbiosis: Fashioning out cities to respond to a climate challenged world”
hyper-local food
Graze the Roof project managers/garden educators Nik and Lindsey Dyer || photo by Michael I. Mandel
North Carolinians, you’re in luck! You’re lust for local food journalism has been assuaged by Food Life, a new foodie magazine recently released by parent company Sophie Magazine. The budding farm-to-fork publication has taken an interest in rooftop agriculture by including an article by yours truly in the current (Summer 2014) issue. If you’re in the Tar Heel State you can pick up a copy of the magazine, hot off the press. If you’re not, here’s a reprint of the article for your reading pleasure:
Hyper-Local Food: Implementing Rooftop Agriculture
by Lauren Mandel, MLA, ASLA
Strolling through the florescent-lit aisles of my local market I peruse the fine print on the packaged produce: vine-ripened tomatoes from California, organic Mexican-grown avocados, pesticide-free Idaho potatoes. Disillusioned by the noticeable lack of “local,” I leave my basket and walk out the door.
Now let’s get one thing straight. I love to eat. There’s nothing better than a delicious home-cooked dinner with friends and a few bottles of red. Any chef worth her weight in beans, though, will tell you that the secret to a delicious meal is fresh ingredients. Freshly harvested fruits and veggies bring intense flavors, crisp textures and plentiful nutrients. These prized qualities decline in many types of produce after harvest, which means that if you want fresh, you better buy local.
In Philadelphia – where I work as a landscape architect and green roof designer – local is fairly easy to find. Farm-to-fork restaurants, accessible CSAs and a strong farmers’ market scene mean that urbanites in my city know the taste of good food. In recent years, the quest for local has inspired many Philadelphians to take it up a notch by growing their own food; an idea that harks back to the victory gardens of World Wars I and II, but with a modern twist. Back yards, front stoops, fire escapes, windowsills and community gardens provide the space today’s urban gardeners need to cultivate freshness.
But what if you don’t have a yard or a community garden plot? What if your fire escape doesn’t get enough sun to grow your beloved eggplant? Urbanites across North America have converged on a creative solution to this common predicament: rooftop agriculture.
This hyper-local food movement is gaining momentum as urban gardeners and farmers realize the potential of the empty acres above us. Rooftop agriculture allows food to travel 50 feet rather than 50 miles, or 500 miles! The movement provides an avenue for homeowners, students, restaurateurs and urban farmers to grow their own fresh, delicious food close to home while repurposing underutilized space and getting a little sun-kissed exercise. The city governments of Philadelphia, New York, Toronto and Portland, OR additionally applaud rooftop agriculture for its ability to manage stormwater runoff.
During the past five years I traveled around North America visiting rooftop gardens and farms and meeting the inspiring growers behind each skyline gem. I spoke with women and men, kids as young as four, and people of all ethnicities who are invested in rooftop agriculture each for a different reason. Whether growing rooftop crops in containers, raised beds, a row farm or greenhouse, one thing is clear: rooftop agriculture reconnects us with our food.
This message of reconnection rings true at Graze the Roof, where neighborhood kids learn about gardening and healthy eating atop a church roof in San Francisco’s Tenderloin district. The message is clear at Eagle Street Rooftop Farm in Brooklyn, where volunteers reach deeply into the soil. The message speaks magnitudes at Lufa Farms, which provides Montreal residents with year-round, local produce from hydroponic rooftop farms. The message may resonate with you, as you harvest perfectly ripened fruits from your own rooftop garden.
Now is the time to reconnect with our food. Whether this means buying local or growing your own, remember that you can make a difference while enjoying the taste of freshness. Bon appétit!
(c) 2014 Lauren Mandel. All rights reserved
learning from Cuba
Cuban agricultural field || photo by Karen Jacobson
Let’s face it, we’re all a little obsessed with our own garden. I spend time with my rooftop vegetables like any good gardener and talk to friends about their latest gardening fads and experiments. But what if we stepped back and thought about rooftop agriculture at a larger scale? What if we looked to other cities or even countries to learn from comprehensive urban agricultural strategies? With a global eye on agriculture we can identify which methodologies and technologies from abroad can be extracted, combined and applied to our skyline to further the rooftop agriculture industry.
Cuban food market || photo by Karen Jacobson
In the 1990s, Cuba implemented a national agricultural strategy as a solution to hunger. When the formerly import-dependent country experienced Soviet import sanctions in the 1990s (compounding the existing U.S. embargo and worsened by allied acts in 1992 and 1996), access to imported oil, farming equipment, agricultural chemicals and food became practically nonexistent. Cubans were forced to curb their oil use by minimizing gas-powered equipment operation (a staple of industrial-scale agriculture) as well as food transportation, refrigeration and storage. These changes particularly impacted the 75% of Cubans living in urban areas,¹ who now had little access to food. Cuba’s agricultural sector was devastated. As a result, the Organic Revolution shifted food production from rural farms to cities in order to better serve population centers.
Cuba’s reorientation towards small, organic and semi-organic urban farms began with community initiative. The government followed suit by establishing an Urban Agriculture Department within the Ministry of Agriculture, with a goal of converting all of Havana’s vacant land into productive farmland. In less than a decade over 30% of Havana’s vacant urban land became repurposed for organic agriculture, with 8,000 farms and gardens in Havana alone and more than 30,000 Cubans directly engaged in production.²
The most common type of garden in Cuba is the huerto popular, commonly called “popular garden.” These small, residential gardens on state-owned land are cultivated by individuals and community groups in urban areas. Gardens throughout the country range in size from a few square yards to 7.5 acres.³ Larger gardens are commonly divided into smaller plots and can be cultivated by coordinated groups of households reaching upwards of 70 people, generally men.
Organically grown carrots || photo by Karen Jacobson
Cuban produce vendor || photo by Karen Jacobson
Out of necessity, the Organic Revolution emphasized high-yield production without the use of chemical inputs or agricultural machinery. To clarify, the use of the word “organic” in this context does not refer to an organic certification (as it does in other countries like the U.S.), but rather the practice of chemical-free production. Cuba’s primary organic farming and gardening practices include the widespread use of intercropping (growing multiple crops together in a single area), integrated pest management (IPM, managing insect pest populations without chemicals), supplementing with organic amendments (compost, vermicomost, manure), the utilization of livestock and the promotion of cooperation and information sharing through horticultural clubs. Cuban scientists also contributed to the advancement of organic practices, particularly within the field of IPM. Many of these farming practices were actually used in Cuba before industrial agriculture too root, so the Organic Revolution caused somewhat of a “back to basics” approach to farming.
Up on the roof, mechanized equipment is impractical and chemicals are generally avoided. These similarities set the stage for considering which Cuban agricultural techniques could be applied to our skyline to maximize yields in rooftop row farms and raised beds. The chart below describes what works in the Cuban agricultural sector, why it works and what techniques can be extracted and applied to rooftop agriculture. Here are the CliffsNotes, for your ruminating pleasure:
1| Organic agricultural techniques: Promote chemical-free production strategies that maximize species diversity, soil health and pest control.
2| Online forums and blogging: Share rooftop agricultural knowledge through online forums and publicly accessible research.
3| Coordinated, city-wide strategy: Forward infrastructure and policy through coordinated efforts of government, city planners and growers.
4| Recognition of the need: Consider rooftop agriculture’s potential in providing fresh food to communities in need and recognize the importance of food localization.
Cuban agriculture analysis + application to rooftop agriculture || by Lauren Mandel
¹ Central Intelligence Agency. 2009. The World Factbook: Cuba. Accessed 15 January 2010. <www.cia.gov/library/publications/the-world-factbook/geos/cu.html>.
² Murphy, C. 1999. Cultivating Havana: Urban agriculture and food security in the years of crisis. Institute for Food and Development Report, no. 12.
³ Warwick, Hugh. 1999. Cuba’s organic revolution. The Ecologist, vol. 29, no. 8.
Staten Island gets fresh
On the edge of Staten Island’s harbor district an energetic team will soon “ferry” roof-fresh produce from an historic building to those in need. The site: the Staten Island Ferry Terminal.
The Department of Transportation introduced a 13,000 square foot Sedum and perennial green roof atop the Ferry Terminal’s water filtration building during a 2005 building renovation for the purposes of managing stormwater and improving the scenery from an adjacent viewing deck. By 2013, though, the green roof’s dwindling maintenance budget had resulted in a defunct irrigation system and invasive species takeover by rapidly colonizing plants. What was once a sleek emerald veneer had become an unwieldy mess. Could this green roof be restored or re-purposed?
Staten Island Ferry Terminal weed removal || photo by Adrian Wilton
Bare soil, ready for agricultural media || photo by Adrian Wilton
Enter Living Restoration, LLC, a Staten Island-based edible landscaping company determined to convert the green roof into a working farm. In April 2013 Project Director Adrian Wilton began the conversion by removing weeds and irrigation lines from a 1,200 square foot (0.03 acre) area with the help of countless volunteers. The team later installed agricultural growth media to bring the depleted media depth up to between seven and eight-inches and then planted rows of garlic.
In partnership with New York Cares (to mobilize volunteers) and Community Health Action of Staten Island (to distribute food to low income residents through food pantries) Wilton plans to convert additional acreage to bring 9,000 square feet (0.2-acres) into leafy green production and 2,400 square feet (0.06 acre) into ornamental perennial beds. “The roof is divided into plots by walkways; we’re using these plots to structure the farm” says Wilton, who predicts that hardy greens like kale and even cabbage will perform well on the roof. The roof-fresh produce will provide welcome ingredients for Port Richmond High School‘s culinary students, who plan to hold cooking classes at local food pantries to extend the farm’s outreach.
Skyline farms exist throughout other New York City boroughs, namely Brooklyn and Queens, but the Ferry Terminal rooftop farm is a first for Staten Island. “It’s a great way to educate everyone about uses for green roofs,” explains Wilton, who anticipates high visibility resulting from the neighborhood’s rapid development and high ferry user traffic.
With all eyes on the Ferry Terminal roof, we may just see a crop of new rooftop farms sprout up across Staten Island’s skyline.
Postcard rendering of the rooftop farm || by Living Restoration, LLC
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If you live in Staten Island we want to hear what you think about this project! Leave a comment below or post a note at the EAT UP Facebook page.