{"id":53,"date":"2026-10-05T12:57:18","date_gmt":"2026-10-05T16:57:18","guid":{"rendered":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/chapter\/enabling-rooftop-agriculture-learning-from-toronto-and-beyond\/"},"modified":"2026-10-05T13:04:45","modified_gmt":"2026-10-05T17:04:45","slug":"enabling-rooftop-agriculture-learning-from-toronto-and-beyond","status":"publish","type":"chapter","link":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/chapter\/enabling-rooftop-agriculture-learning-from-toronto-and-beyond\/","title":{"raw":"11. Enabling Rooftop Agriculture: Learning from Toronto and Beyond","rendered":"11. Enabling Rooftop Agriculture: Learning from Toronto and Beyond"},"content":{"raw":"\n

Abstract<\/h2>\nAs cities densify, rooftops offer space for food production, learning, and community activity. This chapter examines the development of productive green roofs in Toronto, focusing on teaching, design, research, and farming at Toronto Metropolitan University (TMU). It considers how municipal green roof policies and incentives have supported rooftop projects, while noting that these measures have not required food production. Drawing on student design proposals, educational initiatives, and the development of TMU\u2019s two rooftop farm sites, the chapter identifies practical considerations for adapting roofs to growing food, including structural capacity, safe access, growing conditions, and ongoing maintenance. The TMU Urban Farm illustrates how rooftop spaces can support research, farmer training, food distribution, and initiatives centred on Black food sovereignty and Indigenous foodways. These examples show how rooftop agriculture can improve food availability, agency, and acceptability while creating opportunities for community engagement and knowledge sharing. The chapter argues that, with appropriate design and sustained institutional support, productive roofs can become a valuable part of urban food systems.\n

I - Introduction<\/h2>\nAt Toronto Metropolitan University (formerly Ryerson University), researchers, teachers, and students have investigated green roofs for decades. Now, they also look at these sites as opportunities for food production. Supported by the Centre for Studies in Food Security (CSFS), several instructors and students are actively researching and designing rooftop growing spaces. Their involvement includes a variety of approaches, from examining technical issues and proposing new design initiatives to reviewing existing designs, understanding environmental concerns and benefits, crafting pedagogical initiatives, and surveying productive and other forms of green roofs.\n\nGreen roofs not only enhance a city's foodscape, but also create pollinator corridors, serve as teaching gardens and community spaces, decrease stormwater runoff, reduce the urban heat island effect, increase a building's heating and cooling efficiency, and provide calm retreats for the community. Such growing spaces can be an important resource for improving food security, particularly in our densifying urban cores. Availability (access to food), agency (policies and processes to enable food access), and acceptability (culturally appropriate food), three of the 5As of Food Security identified by CSFS, can be addressed by providing food-growing spaces, configured as demonstration\/teaching gardens, allotment garden plots, community gardens, and\/or market garden farms on rooftops where people work and live. But for that to happen, certain design elements must be addressed. Only certain types of roof conditions are suitable for productive food-growing spaces. Much learning is needed for the successful implementation of rooftop gardens.\n\nIn this chapter, we examine teaching and learning about green roof design and farming at Toronto Metropolitan University (section III). Supported by instructors and researchers at the Faculty of Engineering and Architectural Science (FEAS), TMU students have presented work examining the recent development of productive rooftops to help understand the strategies and benefits of growing on roofs, and what works when planning purpose-built or retrofitted productive roofs. This learning strategy is also evident in the two current rooftop gardens at TMU (section IV). We start (section II), however, with guidelines and bylaws, which created the context for the evolution of rooftop farming in Toronto.\n

II - Rooftop Gardens in Toronto: Guidelines and Bylaws<\/h2>\nThe practice of growing food on rooftops is not new, but a recent increase in such practices suggests that a review of research and implementation of these spaces, their potential, and their evolution can point to ways we can enhance food security while mitigating other urban problems. Toronto's green roof initiatives began decades ago. Mountain Equipment Co-op, a sporting goods store, installed one of Toronto's first green roofs in 1998. The Toronto-based non-profit Green Roofs for Healthy Cities was founded the following year, strengthening the movement (Green Roofs for Healthy Cities, 2025). Around the same time, researchers, including some at TMU, studied how and where to install green roofs and their impacts. We can see this in the work of university students. In 2000, the TMU architecture student Liz McElcheran proposed greening the elevated walkway surrounding Toronto's City Hall in her design thesis. McElcheran cited a 1999 Canada Mortgage and Housing Corporation (CMHC) green roof study and the existing Mountain Equipment Co-op roof to argue for the desirability and feasibility of this transformation. Although she does not present it as a productive roof, her thesis plausibly lays out a strategy for a food-centred retrofit and discusses the benefits, using many historical examples to bolster her proposal. McElcheran carefully outlined the safety issues involved in designing habitable (productive and\/or recreational) green roof retrofits, listing lighting, parapets, fire safety, and, of course, load requirements as crucial design concerns (McElcheran, 2000).\n\nNot long afterwards, in 2004, the Andrew and Valerie Pringle Environmental Green Roof was incorporated into TMU's new George Vari Engineering and Computing Centre. Originally planted with flowers (in a relatively deep planting bed) to provide a pleasant visual impact for residents of a neighbouring condominium, the roof was later transformed into a productive green roof: the TMU Farm. The Farm was a student-led initiative that began years later and will be discussed further below.\n\nBy 2009, a report led by TMU Professor Hitesh Doshi, also chair of the City of Toronto Green Roof Technical Advisory Group, resulted in the enactment of Toronto's Green Roof Bylaws nine years after McElcheran's forward-thinking thesis proposal and the installation of TMU\u2019s Pringle Green Roof. The bylaws, along with supplementary guidelines, promoted and still enable green roof projects throughout the city, many of which include or are dedicated to food production.\n\nFrom condominium and restaurant roofs to school and organic grocery store roofs, many productive growing spaces have been installed, totalling more than 1200 green roofs since the introduction of Toronto's bylaws (City of Toronto, 2017a; Liao & Drake, 2025).\n

How Green Roof Guidelines Enable Rooftop Urban Agriculture<\/h3>\nAlthough Toronto installed a number of green roofs more than 20 years ago, the practice has expanded since guidelines and bylaws were introduced in 2009. Over the last 15 years, Toronto has implemented its Green Roof Bylaw to decrease stormwater runoff, mitigate the heat-island effect, and more. Although the program expanded to include an Eco-Roof (both green and cool roof) Incentive Program, the bylaws have never required productive green roofs (for food production). That said, urban farms and community gardens on rooftops might be less prevalent without the financial incentive program that helps cover implementation costs.\n\nSince implementation, the City has supported the installation of 627 Eco-Roof projects. The City could afford this program through fees collected from variances or exemptions for applicants who could not or would not install an eco-roof. When the bylaws required it, applicants paid cash in lieu of constructing an eco-roof. The Province of Ontario's recent removal of the green roof requirement may endanger funding for this incentive program, which, at the time of writing, is still in place.\n\nUntil recently, the City of Toronto required all new buildings (or additions 2,000 square meters or larger in gross floor area) to comply with eco-roof requirements. In November 2025, the Province of Ontario made this requirement voluntary. However, it is still recommended that all new industrial buildings, \"big box\" stores, and any building with a sizable roof install a green roof or reflective-material roof. Perhaps even more significant than the former requirement is that building owners are seeing the benefits of green roofs.\n\nBoth productive rooftops that have benefited from Toronto's Eco-Roof program and roofs that don't qualify for subsidies are sprouting up across the city. One beneficiary was the Carrot Commons roof, a retrofit that showcases a variety of growing strategies to the public. Because of the Eco-Roof Incentive Program's specific constraints, Regent Park's rooftop raised-bed gardens for residents in apartment buildings built by The Daniels Corporation did not qualify for subsidies. Although raised-bed garden plots have been installed, they do not currently qualify for incentives. Nonetheless, these gardens are successful because of careful planning and professional guidance on growing (City of Toronto, 2017c; HoffmannHayes, n.d.).\n\n[caption id=\"attachment_50\" align=\"alignnone\" width=\"747\"]\"Raised Raised beds for community gardening on an apartment building roof in Regent Park, Toronto (Photo by Joe Nasr).[\/caption]\n

Guidelines Beyond Toronto<\/h3>\nExamples worthy of attention come from North America more generally, as well as Halifax, Calgary, and Montreal:\n\nAs far back as 2006, the Canadian Mortgage and Housing Corporation (CMHC) published a resource manual to help municipalities create green roof guidelines and policy (Lawlor et al., 2006). Drawing on ideas from 24 urban regions across Canada, the US, and internationally, it explains the basics of green roof technology and offers general ways to calculate the benefits. This manual does not discuss edible or otherwise productive landscaping, although it can serve as a basis for many other guidelines.\n\nHalifax, Nova Scotia, created a manual in 2009 (Leung et al., 2009) that includes green roof guidelines in its Administrative Order addressing stormwater runoff. However, the document does not mention urban agriculture as a component of these roof strategies (HRM & Halifax Water, 2020).\n\nCalgary, Alberta, published guidelines in 2014 and included a section on green roofs in its 2007 stormwater control handbook (City of Calgary, 2014). Notably, Calgary now has a residential container garden rooftop farm atop a 2022 apartment building called GROW and a rooftop vegetable garden, designed in 2023 for Southcentre Mall, which was not originally designed for a green roof (Mazade, 2024). The mall project takes advantage of the large roof expanse available at a shopping mall (Southcentre Mall, n.d.). Food grown here benefits a non-profit, Made by Momma, that helps provide access to healthy prepared meals (Southcentre Mall, n.d.).\n\nSignificantly, Montreal's green roof guidelines include a section on accessible green roofs\u2014roofs designed to be safely accessed by residents and maintenance staff (Arteau, 2014). Although these technically rigorous guidelines do not directly address food production, there is a tacit understanding that some future roofs will be designed for this purpose.\n

III - Teaching and Learning About Green Roof Design and Farming<\/h2>\nDesign strategies for creating various kinds of green roofs are now taught in many schools and in continuing education courses. From feasibility studies to design and implementation, students propose a variety of green roofs at different scales and on different building types. Some cities have guidelines to support this process, such as the City of Toronto's Green Roof Construction Standard (City of Toronto, 2017b).\n\nStemming from teaching and research, a 2008 symposium at the TMU Department of Architectural Science (DAS), supported by CSFS \u2013 \"The Role of Food and Agriculture in the Design and Planning of Buildings and Cities\" \u2013 looked at green roofs as one of the design opportunities for scaling up food production in urban areas. A DAS research team of faculty and students followed this symposium with an exhibit at Toronto's Design Exchange called Carrot City: Designing for Urban Agriculture. The exhibit featured both realized urban agriculture projects and theoretical work by students in the DAS program, including productive green roofs as a fundamental design category for urban agriculture. This exhibit, an accompanying book and site<\/a> travelled to many cities, adding case studies along the way and increased knowledge of design strategies for urban agriculture, including rooftop projects (Gorgolewski et al., 2011).\n\nDAS is one of many architecture programs that teach green, productive roofs at various scales. Design and theory courses throughout the curriculum familiarize students with productive roofs. Upper-level courses with themes such as designing the productive city and creating local food landscapes help students imagine what a robust urban agriculture strategy for Toronto and other urban environments could look like, including using rooftops to meet strategic goals.[footnote]Specifically, courses such as Mark Gorgolewski's \"Architecture Option Studio: Creating Local Food Landscapes' and the course \"Creating the Productive City,\" taught both as a lecture course and design studio, addressed green roof design in its early years; GRHC focused primarily on green roofs more generally, not specifically on implementation.[\/footnote] In addition, several students in the DAS Master's programs have made this subject the central focus of their theses.\n\nContinuing education programs are also essential for enabling green roof design and maintenance, including productive ones. They can help increase the number of productive green roofs. Within TMU's Chang School, the Food Security Certificate Program has taught food security, including growing food on rooftops, since 2003. The instructors teach about the 5As of Food Security: availability, accessibility, adequacy, acceptability, and agency, through their courses (see Chapter 12).\n\nOne notable continuing education initiative beyond the university environment in Toronto is the Living Architecture Academy, an initiative of Green Roofs for Healthy Cities. Both design and theory courses provide contractors, engineers, and architects with technical, theoretical, and design skills needed to incorporate productive growing spaces into buildings as an integral part of the project (Green Roofs for Healthy Cities, 2025).  In its early years, GRHC focused primarily on green roofs more generally, not specifically on implementing productive green roofs. However, the potential of productive roofscapes soon became evident. Their Cities Alive Conferences fostered new ideas about the potential of green roofs, including ideas from the Conference's student design challenge. In 2009, the winning Student Design Challenge team was from DAS. The architecture students proposed food-growing spaces in the commercial strip of Cliffside Village, Toronto. By relocating parking lots to an underground garage and placing a productive green roof on the at-grade garage roof, they located growing spaces where residents live and shop. Food production was visible, convenient, and part of the urban fabric. This design for ease of access to food-growing spaces can be seen as a strategic way to enable both availability and culturally acceptable food \u2013 two of the 5As of Food Security (mentioned above).[footnote]The team entry was called \u201cCliffside Village, Scarborough, Canada, despite higher investment and maintenance costs, higher-profile plants provide greater energy efficiency (particularly by \u201d (an urban agriculture strategy for strip mall developments). Team members: D. Feinmesser, Y. Mityuryayeva, T. Tso, and A. Hendershott. 2009.[\/footnote]\n\nThe potential for creating food-producing rooftop spaces became even clearer when Green Roofs for Healthy Cities and other food security advocates in Toronto (FoodShare Toronto, Toronto Food Policy Council, and urban farm organizations) partnered with the CSFS for an international Urban Agriculture Summit at Ryerson University in 2012. The international summit included presentations from farmers, including rooftop farmers, as well as architects, practitioners, educators, and researchers. Since then, rooftop food production has increased tremendously, and recent research is helping build knowledge in the field.\n\nNot long after the Summit, in 2013, FoodShare Toronto and the Toronto District School Board created the Eastdale Collegiate rooftop farm. Funding from several foundations helped launch this almost 1,500-square-meter rooftop project, designed to teach high school students about all aspects of growing, preparing, and selling food. This hands-on educational project shows the importance of educating the next generation to be food producers. These youth could build careers from the hands-on experience this farm initiative provides, or at the very least, gain the knowledge to grow food of their choosing (acceptable, culturally appropriate food) and appreciate the fresh, local food they buy in local markets (Brown, 2013).\n

How Do Students Envision the Future of Productive Roofs?<\/h3>\nTMU's Department of Architectural Science, the Program of Environmental Applied Science and Management (EnSciMan), and Urban and Regional Planning students have been researching green roofs and productive green roofs. Some of their supervisors are CSFS Associates, who see a strong connection between urban rooftop growing and food security. The student work ranges from the practical to the visionary, like McElcheran's architecture thesis mentioned above. Some argue for installing green roofs for environmental reasons, such as Beth Anne Currie's (2005) thesis, which studied how green roofs populated with a variety of plantings mitigate air pollution in Toronto. Beyond design studies, emerging research from several fields offers useful tools for architects designing green roofs and for farmers\/managers implementing rooftop urban agriculture initiatives. One such study is Angela Yick Ting Au's (2007) TMU EnSciMan program master's thesis: A Planning Tool of Urban Green Roofs.\n\nAu's (2007) study to develop a planning tool for green roofs looked at two factors \u2013 stormwater runoff and energy benefits \u2013 but not the potential for food production. Within these two factors, Au notes differences in outcomes for extensive roofs (using ground-cover plants such as sedum) and intensive roofs (higher plants that can include bushes and trees, and, of course, agricultural plants) (Au, 2007). Their study emphasizes that, despite higher investment and maintenance costs, higher-profile plants provide greater energy efficiency (particularly by mitigating the urban heat island effect) and stormwater retention (Au, 2007). Although the data reported in Au's thesis are now dated, one valuable aspect of their study is the notion that green roofs are more beneficial when many factors are measured. Adding another factor \u2013 food production \u2013 provides a greater value for a green roof, as noted in the many ways the TMU roofs are used.\n\nResearchers at TMU, the University of Toronto and beyond have been gathering data about how different types of plantings can be beneficial in a variety of ways. Studies comparing the results of different planting strategies and species on rooftops can help us understand the benefits of planting agricultural plants on deeper-soil roofs (intensive rooftops) instead of sedum or other low plants in shallow rooftop soil conditions (extensive rooftops). Some researchers are examining differences in evapotranspiration under different conditions and with a variety of plants. Evapotranspiration is the transfer of water into the atmosphere through evaporation and transpiration. One research question is whether taller plants requiring deeper soil (such as food crops) outperform sedum (which needs shallower soil media) in evapotranspiration and the resulting benefits to the building and the microclimate around the roof (O'Carroll et al., 2023).\n\nWhen paired with the findings of another ENSCIMAN thesis, Assessing the Communication Network of a Budding Industry: Rooftop Urban Agriculture in Toronto, by Daphne Page (2014), we can hypothesize that sharing knowledge about rooftop food production would be a key factor in strengthening food production capacity in dense urban areas. The thesis examines civic food networks (CFNs) in relation to local food movements and emerging rooftop urban agricultural initiatives (Page, 2014). Page (2014) explores the knowledge-sharing potential that would help expand both the implementation and success of rooftop urban agriculture in Toronto and elsewhere. She conducted her research when rooftop farming was relatively new, and examples were scarce. Indeed, even today, sizable projects are still uncommon. Beyond the number of examples, rooftop growing still faces many challenges, from weight constraints that require engineered soil to finding buildings that are appropriate for, or adaptable to, production (Page, 2014). The need for effective knowledge sharing is palpable.\n\nIn TMU's School of Urban and Regional Planning, Jack Douglas Lawson's (2021) thesis, A Pathway to Rooftops: A Feasibility Study of Green Roof Typologies at 105 Bond Street, explored what downtown Toronto would look like with green roofs added to existing buildings. His example, a 1920s building on the TMU campus, demonstrates the challenges of retrofits; yet, despite pre-existing mechanical systems, elevator penthouses, stair headhouses, skylights, and other obstructions, the thesis shows a feasible strategy (Lawson, 2021). The proposal includes \"1) a holistic meeting space for students, faculty and school-side donors or stakeholders on its lower tier along with both (2) a native pollinator garden, and (3) research and food production beds on the upper tier\" (Lawson, 2021, p. 11). Many well-known urban rooftop farms are located on retrofitted existing buildings, notably Gotham Greens and Brooklyn Grange in New York City (Page, 2014). The TMU Engineering roof, while purpose-built as a green roof, needed considerable modifications when the commitment was made to transform it from its original form as a field of flowers into a productive space. The constant presence of farmers, students, volunteers, and visitors is one of the biggest shifts to consider when designing productive roofs rather than other green roof types.\n\nWhat is potentially more exciting, as we teach the design and engineering aspects of productive green roofs, is the prospect of architects educating clients about the advantages of including a rooftop farm or allotment garden space in the program from the start. One example is the Garden Village project\u2014a Berkeley, California, student housing complex from 2017 \u2014designed with rooftop farms on every building (RAD Urban, n.d.).\n

Design Proposals from TMU\u2019s Department of Architectural Science<\/h3>\nWithin the Department of Architectural Science, Bijan Ghazizadeh\u2019s (2015) master\u2019s thesis envisioned an elevated corridor that would create a Continuous Productive Urban Landscape (CPUL) in downtown Toronto. The proposal drew inspiration from the Continuous Productive Urban Landscape (CPUL) concept developed by Andr\u00e9 Viljoen and Katrin Bohn for London, UK (Viljoen, 2005; Viljoen & Bohn, 2009). In his thesis, The Gardiner SkyPark: Continuous Productive Urban Landscape as Infrastructure, Ghazizadeh (2015) proposed integrating pollinator gardens, linear park space, and productive community gardens into an elevated route through the city, giving urban residents access to growing spaces. The SkyPark would also create a car-free recreational and nature corridor for walking, jogging, and cycling, weaving through downtown Toronto, crossing the Gardiner Expressway, and ultimately terminating at Lake Ontario, while providing access to and views of garden spaces along the route (Ghazizadeh, 2015).\n\n[caption id=\"attachment_50\" align=\"alignnone\" width=\"780\"]\"Rendering Productive urban landscape rendering (from Bijan Ghazizadeh's thesis proposal).[\/caption]\n\nEric Cheung's (2025) TMU architecture master's thesis, A Place for Urban Food Systems, envisions a food hub with a productive green roof to bring fresh local food to Scarborough, a borough of Toronto with comparatively limited access to farmers' markets, community growing spaces, and urban farms. A central concern was providing access to culturally appropriate food (acceptability) to this largely immigrant population (Cheung, 2025). This adaptive reuse proposal addresses the recently abandoned elevated Scarborough Rapid Transit (Scarborough RT) rail line and its sizable metro and bus station. Cheung\u2019s proposal transforms the aging infrastructure running through Scarborough Centre into a linear elevated farm on the rail line, with a food hub below. The design proposal includes raised garden beds, trellised growing spaces, greenhouses on the elevated structure for year-round growing, an elevated walking path that traverses Scarborough's urban core, and spaces for a farmers' market, food processing, teaching kitchens, and food shops inside the former metro station (Cheung, 2025). Here, the rooftop farm component is part of a larger food hub system.\n\n[caption id=\"attachment_50\" align=\"alignnone\" width=\"757\"]\"Rendering Proposed food hub in Scarborough rendering: Toronto showing the elevated productive space on a former rail line (from Eric Cheung's thesis proposal).[\/caption]\n\nOne of Cheung\u2019s (2025) central concerns was access to culturally appropriate food for the largely immigrant community the proposed food hub would serve. As in McElcheran\u2019s (2000) thesis, case studies demonstrated the feasibility of the design proposal. Examples of linear elevated gardens, including the Coul\u00e9e Verte Ren\u00e9-Dumont (also known as the Promenade Plant\u00e9e) in Paris and the High Line in New York City, showed how elevated urban infrastructure can be transformed into green, recreational space. La Cit\u00e9 Mara\u00eech\u00e8re in Romainville, just outside Paris, provided another model: a community teaching greenhouse integrated into a broader community food hub. Together, these examples informed a potentially iconic project intended to provide \u201cvisible and accessible opportunities for public participation in food systems in unexpected places\u201d (Cheung, 2025, p. 4).\n\n[caption id=\"attachment_50\" align=\"alignnone\" width=\"593\"]\"Greenhouse Greenhouse and food hub \"La Cit\u00e9 Mara\u00eech\u00e8re\" in Romainville, near Paris, France (Photo by Joe Nasr).[\/caption]\n\nIn TMU's Department of Architectural Science, instructors crafted problems (design briefs) that included rooftop farms and other green roofs for their students to solve in their design studios.  The 2nd-year design studio has included a green roof for several years as part of library design projects. In fall 2025, the 2nd-year project design brief shifted to an even more food-focused project: a productive roof above a food hub.[footnote] 2nd-year design studios in 2024 were led by Dr. Terri Peters; the 2025 food hub project is part of the 2nd-year design studio led by Dr. Dustin Valen.[\/footnote] From early design studios to graduate school thesis projects, students are learning about and promoting solutions to green our cities and expand local food production and access.\n

IV - Rooftop Urban Farm at Toronto Metropolitan University<\/h2>\nBeyond theoretical proposals, TMU students began putting urban food production into practice at an opportune moment. In 2011, two nutrition students, Catherine Lung and Stephanie Nishi, proposed growing vegetables on unused campus plots. With support from the Centre for Studies in Food Security and a design-build team of Department of Architectural Science students using recycled materials, Rye\u2019s HomeGrown was born. Led by Lung, the initiative expanded to nine ground-level sites across campus, ranging from a garden designed for campus preschoolers to a street-front garden near the Student Campus Centre showcasing crops from around the world. Following a small experimental plot on a green roof in 2013, the roofscape was transformed between 2014 and 2016 into a major expansion of Rye\u2019s HomeGrown.\n\nToday, TMU has rooftop growing spaces on two campus buildings, the Pringle roof on the Engineering building (mentioned above) and the podium roof of a recently built classroom and dormitory building\u2013the Daphne Cockwell Complex (DCC). The DCC roof includes tool storage and a large gathering space with a deployable sunshade on a large steel frame, enabling workshops, food events, and relief from the heat for farmers. Its sizable greenhouse has become a multi-functional space. The rooftops support food growing, distribution, community engagement through workshops and tours, food justice initiatives, and broader promotion of food literacy (Toronto Metropolitan University, 2019).\n\nThe TMU Urban Farm and the CSFS partner in administering faculty- and graduate student-led research on the roofs. This \"Living Lab\" research on the roofs provides the seeds for understanding the impact food-producing roofs have on buildings, neighbourhoods, and cities. The TMU farm's second rooftop on the DCC building shows how green roofs can serve as sustainability and amenity spaces, as well as productive growing spaces, opening up possibilities for stronger community engagement and more. These growing spaces can be an important part of strategies to increase food sovereignty, availability, and knowledge about food and culture (Living Lab, n.d.).\n\nThe TMU Urban Farm hosts a hands-on Rooftop Farmer Training Program. It is also the site of Black Food Sovereignty initiatives on the roofs: The Harvest Collective and the Learning Circle bring to the Black faculty, staff, and student community the opportunity to enjoy the harvest of medicinal and food crops that are traditional to the African Diaspora and, until recently, difficult to find in Toronto. Another Farm project, the Indigenous Foodways program, \"supports and celebrates traditional Indigenous ecological knowledge and ways of growing\" (TMU Urban Farm, n.d.; Walker, 2026).\n\n \n\n[caption id=\"attachment_50\" align=\"alignnone\" width=\"670\"]\"Toronto Toronto Urban Farm at the Pringle roof on the Vari Engineering Building, Toronto Metropolitan University (Photo by Joe Nasr).[\/caption]\n\nFarming on the Pringle green roof changed what was possible to produce on a dense urban campus. During the first years, the Urban Farm Manager, Arlene Throness, and the Urban Farm Operations Coordinator, Jayne Miles, were hired to implement an ambitious transformation. They worked within the green roof's soil-weight limitations, creating low walking paths for farmers and volunteers, enabling built-up deep garden beds for a variety of crops, and focusing on building rich soil for propagation.\n\nWhat began as a small student-led initiative grew through strong stewardship from the Centre for Studies in Food Security, university funding, and a strong relationship with University Business Services. The farm is now a formal department within food services, supported by CSFS, Facilities Management, and FEAS. The many food-growing and research initiatives that now take place at the two Urban Farm sites at TMU engage faculty, students, and the community. With attention to plant nutrition, crop rotation, rooftop weather conditions, soil health, and more, Throness and her team nurture a farm that produces 2,500 kg of food per year. Committed to food justice, one third of the farm's crops are donated to nearby community organizations, one third is sold to the public, and one third is sold at a discount to students. The event space on the DCC roof was designed to help the University and local community learn about, celebrate, and share food together.\n\nOne notable aspect of these two campus rooftop farms is that both were designed as green roofs from the start, although neither was initially intended as a food-producing space. The Engineering green roof, initially built with about four inches of soil and sown with flowers, needed some retrofitting when the farm was introduced. Over time, TMU added sinks for washing produce, irrigation hoses, repeated additions of soil and compost, adequate walking surfaces and barrier fencing that meets rooftop code conditions for human habitation. The DCC roof, always intended to be a habitable green roof, was redesigned for farming before the building was even completed, enabling an easy transformation from a leisure green space for students to a productive roof with an event space for the University and community. A parapet or fencing that meets safety regulations, along with clear walking paths that protect the roof membrane, are crucial for productive roofs. A tool shed, vegetable preparation area, shady space for gardeners, seed propagation areas, and an elevator to transport soil, plants, produce, and tools can further support success.\n

The TMU Farm and the Pandemic<\/h3>\nWhile TMU's original rooftop farm shared and sold its produce in several ways, its contributions to programs alleviating food insecurity increased during the pandemic, showing the importance of local micro-farms in combating supply chain issues. The pandemic disrupted food distribution networks and exacerbated food insecurity among vulnerable populations. Some people were at risk if they left home to shop for food, so access to healthy, fresh food became a struggle. In Toronto, many non-profits responded to pandemic-exacerbated food insecurity, and the TMU rooftop farm helped.\n\nThe rooftop farm donated fresh vegetables and herbs to the Moss Park Market, an initiative of Building Roots, a nearby Toronto non-profit that serves the Moss Park community, a neighbourhood with rent-geared-to-income apartments that was severely impacted by the pandemic. Volunteers at the Market assembled hundreds of food bags weekly at the Market's small shipping-container \"office.\" Although much of the food bag content was purchased, the weekly bags also included fresh vegetables from local farmers and distributors, community gardens, local bakeries, and food grown on the TMU roof. After the pandemic, the TMU Urban Farm continued to contribute to these weekly food bags. In 2023, \"Toronto Metropolitan University\u2019s rooftop urban farm donated 37 crates, totalling 436 lbs [197 kg] of ecologically grown produce over four months\" (TMU Urban Farm, n.d.). Now, after the pandemic, the TMU Urban Farm uses a food distribution model that is designed to serve various communities; one third of the food distribution is donated to both students who are food insecure and Building Roots for its food distribution program, serving the community at large (Building Roots, 2021; Throness, 2023).\n

V - Conclusion<\/h2>\nAs cities densify, ground-level space is at a premium. As cities densify, ground-level space is at a premium. Rooftop surfaces can provide additional space for food production, community activities, pollinator gardens, and other urban uses. From increasing biodiversity in cities to teaching food literacy and promoting cultural knowledge sharing through programs such as the Black Food Sovereignty initiatives and Indigenous Foodways at the TMU Urban Farm, growing where people live and work is a winning proposition. City initiatives such as the Green Roof Bylaws and financial incentive programs often help lead the way. Trends show that rooftop farms and growing spaces are increasing. Heat mitigation, additional recreation and community space, increased urban biodiversity, and, perhaps most important of all, aspects of food security are benefits we can reap from a robust green roof program. As we study more projects like this, the benefits should become increasingly evident.\n\n \n\n \n

References<\/h2>\nArteau, R. (2014). La construction de toits v\u00e9g\u00e9talis\u00e9s: Guide technique pour pr\u00e9parer une solution de rechance<\/a><\/em>. City of Montreal.\n\nAu, A. Y. T. (2007). A planning tool of urban green roofs<\/a><\/em> (Publication No. EC53556) [Master\u2019s thesis, Ryerson University]. ProQuest Dissertations Publishing.\n\nBrown, L. (2013, December 25). Eastdale Collegiate opens its roof to urban agriculture<\/a>. Toronto Star<\/em>.\n\nBuilding Roots. (2021). Moss Park Market<\/a>.\n\nCarrot City. (n.d.). Carrot City: Designing for urban agriculture<\/a>. Toronto Metropolitan University.\n\nCheung, E. (2025). A place for urban food systems [Unpublished master\u2019s thesis]. Toronto Metropolitan University.\n\nCity of Calgary. (2014). Low impact development guidelines: Module 3\u2014Green roofs<\/a>.\n\nCity of Toronto. (2017a). Green roof bylaw<\/a>.\n\nCity of Toronto. (2017b). Toronto green roof construction standard: Supplementary guidelines [PDF]<\/a>.\n\nCity of Toronto. (2017c). Eco-Roof Incentive Program<\/a>.\n\nCurrie, B. A. (2005). Estimates of air pollution mitigation with green roofs using the UFORE model<\/a> <\/em>(Order No. EC53587) [Master\u2019s thesis, Ryerson University]. ProQuest Dissertations & Theses.\n\nGhazizadeh, B. (2015). The Gardiner SkyPark: Continuous productive urban landscape as infrastructure<\/a> <\/em>[Master\u2019s thesis, Ryerson University].\n\nGorgolewski, M., Komisar, J., & Nasr, J. (2011). Carrot City: Creating places for urban agriculture. Monacelli Press.\n\nGreen Roofs for Healthy Cities. (2025). We are North America\u2019s industry association for green roofs and green walls<\/a>.\n\nHoffmannHayes. (n.d.). Our projects<\/a><\/em>.\n\nHRM & Halifax Water. (2020). Stormwater management standards for development activities [PDF].<\/a>\n\nLawlor, G., Currie, B. A., Doshi, H., & Wieditz, I. (2006). Green roofs: A resource manual for municipal policy makers [PDF]<\/a><\/em>. Canada Mortgage and Housing Corporation.\n\nLawson, J. D. (2021). A pathway to rooftops: A feasibility study of green roof typologies at 105 Bond Street<\/a> <\/em>[Master\u2019s thesis, Toronto Metropolitan University].\n\nLeung, M., Karkairan, D., & Keenan, A. (2009). Nova Scotia green roofs manual [PDF].<\/a> Ecology Action Centre<\/em>.\n\nLiao, W., & Drake, J. (2025). Sky-high sustainability: The long-term success of Toronto\u2019s green roofs<\/a>. Living Architecture Monitor<\/em>.\n\nLiving Lab. (n.d.). Research<\/a><\/em>. Toronto Metropolitan University.\n\nMazade, K. (2024, August 16). MODA ramps rooftop garden along Calgary multifamily housing<\/a>. Dezeen.\n\nMcElcheran, L. (2000). Green roof technology: An ecological approach to urban living<\/em> [Unpublished undergraduate thesis]. Ryerson Polytechnic University.\n\nO\u2019Carroll, D. M., Eloisa Sia, M., Staniec, M., Voogt, J. A., Lundholm, J. T., Smart, C. C., & Robinson, C. E. (2023). Influence of vegetation type and climatological conditions on evapotranspiration from extensive green roofs<\/a>. Journal of Hydrology<\/em>, 617, Article 128951.\n\nPage, D. (2014). Assessing the communication network of a budding industry: Rooftop urban agriculture in Toronto<\/a> <\/em>[Master\u2019s thesis, Ryerson University].\n\nRAD Urban. (n.d.). Garden Village<\/a>. Archinect.\n\nSouthcentre Mall. (n.d.). The rooftop garden<\/a>.\n\nThroness, A. (2023). Rooftop Farm Living Lab: Research takes root at the Urban Farm at TMU<\/a><\/em>. Living Architecture Monitor.\n\nTMU Urban Farm. (n.d.). Urban Farm<\/a><\/em>. Toronto Metropolitan University.\n\nToronto Metropolitan University. (2019). How the Ryerson community is shaping urban agriculture<\/a>. Innovation Newsletter<\/em>, 32.\n\nViljoen, A. (Ed.). (2005). Continuous productive urban landscapes: Designing urban agriculture for sustainable cities.<\/em> Architectural Press.\n\nViljoen, A., & Bohn, K. (2009). Continuous productive urban landscape (CPUL): Essential infrastructure and edible ornament<\/a>. Open House International, 34<\/em>(2), 50\u201360.\n\nWalker, A. (2026, June 17). Okra up north: How a forgotten heirloom travelled the African diaspora to Toronto<\/a>. The Guardian<\/em>.\n","rendered":"

Abstract<\/h2>\n

As cities densify, rooftops offer space for food production, learning, and community activity. This chapter examines the development of productive green roofs in Toronto, focusing on teaching, design, research, and farming at Toronto Metropolitan University (TMU). It considers how municipal green roof policies and incentives have supported rooftop projects, while noting that these measures have not required food production. Drawing on student design proposals, educational initiatives, and the development of TMU\u2019s two rooftop farm sites, the chapter identifies practical considerations for adapting roofs to growing food, including structural capacity, safe access, growing conditions, and ongoing maintenance. The TMU Urban Farm illustrates how rooftop spaces can support research, farmer training, food distribution, and initiatives centred on Black food sovereignty and Indigenous foodways. These examples show how rooftop agriculture can improve food availability, agency, and acceptability while creating opportunities for community engagement and knowledge sharing. The chapter argues that, with appropriate design and sustained institutional support, productive roofs can become a valuable part of urban food systems.<\/p>\n

I – Introduction<\/h2>\n

At Toronto Metropolitan University (formerly Ryerson University), researchers, teachers, and students have investigated green roofs for decades. Now, they also look at these sites as opportunities for food production. Supported by the Centre for Studies in Food Security (CSFS), several instructors and students are actively researching and designing rooftop growing spaces. Their involvement includes a variety of approaches, from examining technical issues and proposing new design initiatives to reviewing existing designs, understanding environmental concerns and benefits, crafting pedagogical initiatives, and surveying productive and other forms of green roofs.<\/p>\n

Green roofs not only enhance a city’s foodscape, but also create pollinator corridors, serve as teaching gardens and community spaces, decrease stormwater runoff, reduce the urban heat island effect, increase a building’s heating and cooling efficiency, and provide calm retreats for the community. Such growing spaces can be an important resource for improving food security, particularly in our densifying urban cores. Availability (access to food), agency (policies and processes to enable food access), and acceptability (culturally appropriate food), three of the 5As of Food Security identified by CSFS, can be addressed by providing food-growing spaces, configured as demonstration\/teaching gardens, allotment garden plots, community gardens, and\/or market garden farms on rooftops where people work and live. But for that to happen, certain design elements must be addressed. Only certain types of roof conditions are suitable for productive food-growing spaces. Much learning is needed for the successful implementation of rooftop gardens.<\/p>\n

In this chapter, we examine teaching and learning about green roof design and farming at Toronto Metropolitan University (section III). Supported by instructors and researchers at the Faculty of Engineering and Architectural Science (FEAS), TMU students have presented work examining the recent development of productive rooftops to help understand the strategies and benefits of growing on roofs, and what works when planning purpose-built or retrofitted productive roofs. This learning strategy is also evident in the two current rooftop gardens at TMU (section IV). We start (section II), however, with guidelines and bylaws, which created the context for the evolution of rooftop farming in Toronto.<\/p>\n

II – Rooftop Gardens in Toronto: Guidelines and Bylaws<\/h2>\n

The practice of growing food on rooftops is not new, but a recent increase in such practices suggests that a review of research and implementation of these spaces, their potential, and their evolution can point to ways we can enhance food security while mitigating other urban problems. Toronto’s green roof initiatives began decades ago. Mountain Equipment Co-op, a sporting goods store, installed one of Toronto’s first green roofs in 1998. The Toronto-based non-profit Green Roofs for Healthy Cities was founded the following year, strengthening the movement (Green Roofs for Healthy Cities, 2025). Around the same time, researchers, including some at TMU, studied how and where to install green roofs and their impacts. We can see this in the work of university students. In 2000, the TMU architecture student Liz McElcheran proposed greening the elevated walkway surrounding Toronto’s City Hall in her design thesis. McElcheran cited a 1999 Canada Mortgage and Housing Corporation (CMHC) green roof study and the existing Mountain Equipment Co-op roof to argue for the desirability and feasibility of this transformation. Although she does not present it as a productive roof, her thesis plausibly lays out a strategy for a food-centred retrofit and discusses the benefits, using many historical examples to bolster her proposal. McElcheran carefully outlined the safety issues involved in designing habitable (productive and\/or recreational) green roof retrofits, listing lighting, parapets, fire safety, and, of course, load requirements as crucial design concerns (McElcheran, 2000).<\/p>\n

Not long afterwards, in 2004, the Andrew and Valerie Pringle Environmental Green Roof was incorporated into TMU’s new George Vari Engineering and Computing Centre. Originally planted with flowers (in a relatively deep planting bed) to provide a pleasant visual impact for residents of a neighbouring condominium, the roof was later transformed into a productive green roof: the TMU Farm. The Farm was a student-led initiative that began years later and will be discussed further below.<\/p>\n

By 2009, a report led by TMU Professor Hitesh Doshi, also chair of the City of Toronto Green Roof Technical Advisory Group, resulted in the enactment of Toronto’s Green Roof Bylaws nine years after McElcheran’s forward-thinking thesis proposal and the installation of TMU\u2019s Pringle Green Roof. The bylaws, along with supplementary guidelines, promoted and still enable green roof projects throughout the city, many of which include or are dedicated to food production.<\/p>\n

From condominium and restaurant roofs to school and organic grocery store roofs, many productive growing spaces have been installed, totalling more than 1200 green roofs since the introduction of Toronto’s bylaws (City of Toronto, 2017a; Liao & Drake, 2025).<\/p>\n

How Green Roof Guidelines Enable Rooftop Urban Agriculture<\/h3>\n

Although Toronto installed a number of green roofs more than 20 years ago, the practice has expanded since guidelines and bylaws were introduced in 2009. Over the last 15 years, Toronto has implemented its Green Roof Bylaw to decrease stormwater runoff, mitigate the heat-island effect, and more. Although the program expanded to include an Eco-Roof (both green and cool roof) Incentive Program, the bylaws have never required productive green roofs (for food production). That said, urban farms and community gardens on rooftops might be less prevalent without the financial incentive program that helps cover implementation costs.<\/p>\n

Since implementation, the City has supported the installation of 627 Eco-Roof projects. The City could afford this program through fees collected from variances or exemptions for applicants who could not or would not install an eco-roof. When the bylaws required it, applicants paid cash in lieu of constructing an eco-roof. The Province of Ontario’s recent removal of the green roof requirement may endanger funding for this incentive program, which, at the time of writing, is still in place.<\/p>\n

Until recently, the City of Toronto required all new buildings (or additions 2,000 square meters or larger in gross floor area) to comply with eco-roof requirements. In November 2025, the Province of Ontario made this requirement voluntary. However, it is still recommended that all new industrial buildings, “big box” stores, and any building with a sizable roof install a green roof or reflective-material roof. Perhaps even more significant than the former requirement is that building owners are seeing the benefits of green roofs.<\/p>\n

Both productive rooftops that have benefited from Toronto’s Eco-Roof program and roofs that don’t qualify for subsidies are sprouting up across the city. One beneficiary was the Carrot Commons roof, a retrofit that showcases a variety of growing strategies to the public. Because of the Eco-Roof Incentive Program’s specific constraints, Regent Park’s rooftop raised-bed gardens for residents in apartment buildings built by The Daniels Corporation did not qualify for subsidies. Although raised-bed garden plots have been installed, they do not currently qualify for incentives. Nonetheless, these gardens are successful because of careful planning and professional guidance on growing (City of Toronto, 2017c; HoffmannHayes, n.d.).<\/p>\n

\"Raised
Raised beds for community gardening on an apartment building roof in Regent Park, Toronto (Photo by Joe Nasr).<\/figcaption><\/figure>\n

Guidelines Beyond Toronto<\/h3>\n

Examples worthy of attention come from North America more generally, as well as Halifax, Calgary, and Montreal:<\/p>\n

As far back as 2006, the Canadian Mortgage and Housing Corporation (CMHC) published a resource manual to help municipalities create green roof guidelines and policy (Lawlor et al., 2006). Drawing on ideas from 24 urban regions across Canada, the US, and internationally, it explains the basics of green roof technology and offers general ways to calculate the benefits. This manual does not discuss edible or otherwise productive landscaping, although it can serve as a basis for many other guidelines.<\/p>\n

Halifax, Nova Scotia, created a manual in 2009 (Leung et al., 2009) that includes green roof guidelines in its Administrative Order addressing stormwater runoff. However, the document does not mention urban agriculture as a component of these roof strategies (HRM & Halifax Water, 2020).<\/p>\n

Calgary, Alberta, published guidelines in 2014 and included a section on green roofs in its 2007 stormwater control handbook (City of Calgary, 2014). Notably, Calgary now has a residential container garden rooftop farm atop a 2022 apartment building called GROW and a rooftop vegetable garden, designed in 2023 for Southcentre Mall, which was not originally designed for a green roof (Mazade, 2024). The mall project takes advantage of the large roof expanse available at a shopping mall (Southcentre Mall, n.d.). Food grown here benefits a non-profit, Made by Momma, that helps provide access to healthy prepared meals (Southcentre Mall, n.d.).<\/p>\n

Significantly, Montreal’s green roof guidelines include a section on accessible green roofs\u2014roofs designed to be safely accessed by residents and maintenance staff (Arteau, 2014). Although these technically rigorous guidelines do not directly address food production, there is a tacit understanding that some future roofs will be designed for this purpose.<\/p>\n

III – Teaching and Learning About Green Roof Design and Farming<\/h2>\n

Design strategies for creating various kinds of green roofs are now taught in many schools and in continuing education courses. From feasibility studies to design and implementation, students propose a variety of green roofs at different scales and on different building types. Some cities have guidelines to support this process, such as the City of Toronto’s Green Roof Construction Standard (City of Toronto, 2017b).<\/p>\n

Stemming from teaching and research, a 2008 symposium at the TMU Department of Architectural Science (DAS), supported by CSFS \u2013 “The Role of Food and Agriculture in the Design and Planning of Buildings and Cities” \u2013 looked at green roofs as one of the design opportunities for scaling up food production in urban areas. A DAS research team of faculty and students followed this symposium with an exhibit at Toronto’s Design Exchange called Carrot City: Designing for Urban Agriculture. The exhibit featured both realized urban agriculture projects and theoretical work by students in the DAS program, including productive green roofs as a fundamental design category for urban agriculture. This exhibit, an accompanying book and site<\/a> travelled to many cities, adding case studies along the way and increased knowledge of design strategies for urban agriculture, including rooftop projects (Gorgolewski et al., 2011).<\/p>\n

DAS is one of many architecture programs that teach green, productive roofs at various scales. Design and theory courses throughout the curriculum familiarize students with productive roofs. Upper-level courses with themes such as designing the productive city and creating local food landscapes help students imagine what a robust urban agriculture strategy for Toronto and other urban environments could look like, including using rooftops to meet strategic goals.[1]<\/sup><\/a> In addition, several students in the DAS Master’s programs have made this subject the central focus of their theses.<\/p>\n

Continuing education programs are also essential for enabling green roof design and maintenance, including productive ones. They can help increase the number of productive green roofs. Within TMU’s Chang School, the Food Security Certificate Program has taught food security, including growing food on rooftops, since 2003. The instructors teach about the 5As of Food Security: availability, accessibility, adequacy, acceptability, and agency, through their courses (see Chapter 12).<\/p>\n

One notable continuing education initiative beyond the university environment in Toronto is the Living Architecture Academy, an initiative of Green Roofs for Healthy Cities. Both design and theory courses provide contractors, engineers, and architects with technical, theoretical, and design skills needed to incorporate productive growing spaces into buildings as an integral part of the project (Green Roofs for Healthy Cities, 2025).  In its early years, GRHC focused primarily on green roofs more generally, not specifically on implementing productive green roofs. However, the potential of productive roofscapes soon became evident. Their Cities Alive Conferences fostered new ideas about the potential of green roofs, including ideas from the Conference’s student design challenge. In 2009, the winning Student Design Challenge team was from DAS. The architecture students proposed food-growing spaces in the commercial strip of Cliffside Village, Toronto. By relocating parking lots to an underground garage and placing a productive green roof on the at-grade garage roof, they located growing spaces where residents live and shop. Food production was visible, convenient, and part of the urban fabric. This design for ease of access to food-growing spaces can be seen as a strategic way to enable both availability and culturally acceptable food \u2013 two of the 5As of Food Security (mentioned above).[2]<\/sup><\/a><\/p>\n

The potential for creating food-producing rooftop spaces became even clearer when Green Roofs for Healthy Cities and other food security advocates in Toronto (FoodShare Toronto, Toronto Food Policy Council, and urban farm organizations) partnered with the CSFS for an international Urban Agriculture Summit at Ryerson University in 2012. The international summit included presentations from farmers, including rooftop farmers, as well as architects, practitioners, educators, and researchers. Since then, rooftop food production has increased tremendously, and recent research is helping build knowledge in the field.<\/p>\n

Not long after the Summit, in 2013, FoodShare Toronto and the Toronto District School Board created the Eastdale Collegiate rooftop farm. Funding from several foundations helped launch this almost 1,500-square-meter rooftop project, designed to teach high school students about all aspects of growing, preparing, and selling food. This hands-on educational project shows the importance of educating the next generation to be food producers. These youth could build careers from the hands-on experience this farm initiative provides, or at the very least, gain the knowledge to grow food of their choosing (acceptable, culturally appropriate food) and appreciate the fresh, local food they buy in local markets (Brown, 2013).<\/p>\n

How Do Students Envision the Future of Productive Roofs?<\/h3>\n

TMU’s Department of Architectural Science, the Program of Environmental Applied Science and Management (EnSciMan), and Urban and Regional Planning students have been researching green roofs and productive green roofs. Some of their supervisors are CSFS Associates, who see a strong connection between urban rooftop growing and food security. The student work ranges from the practical to the visionary, like McElcheran’s architecture thesis mentioned above. Some argue for installing green roofs for environmental reasons, such as Beth Anne Currie’s (2005) thesis, which studied how green roofs populated with a variety of plantings mitigate air pollution in Toronto. Beyond design studies, emerging research from several fields offers useful tools for architects designing green roofs and for farmers\/managers implementing rooftop urban agriculture initiatives. One such study is Angela Yick Ting Au’s (2007) TMU EnSciMan program master’s thesis: A Planning Tool of Urban Green Roofs.<\/p>\n

Au’s (2007) study to develop a planning tool for green roofs looked at two factors \u2013 stormwater runoff and energy benefits \u2013 but not the potential for food production. Within these two factors, Au notes differences in outcomes for extensive roofs (using ground-cover plants such as sedum) and intensive roofs (higher plants that can include bushes and trees, and, of course, agricultural plants) (Au, 2007). Their study emphasizes that, despite higher investment and maintenance costs, higher-profile plants provide greater energy efficiency (particularly by mitigating the urban heat island effect) and stormwater retention (Au, 2007). Although the data reported in Au’s thesis are now dated, one valuable aspect of their study is the notion that green roofs are more beneficial when many factors are measured. Adding another factor \u2013 food production \u2013 provides a greater value for a green roof, as noted in the many ways the TMU roofs are used.<\/p>\n

Researchers at TMU, the University of Toronto and beyond have been gathering data about how different types of plantings can be beneficial in a variety of ways. Studies comparing the results of different planting strategies and species on rooftops can help us understand the benefits of planting agricultural plants on deeper-soil roofs (intensive rooftops) instead of sedum or other low plants in shallow rooftop soil conditions (extensive rooftops). Some researchers are examining differences in evapotranspiration under different conditions and with a variety of plants. Evapotranspiration is the transfer of water into the atmosphere through evaporation and transpiration. One research question is whether taller plants requiring deeper soil (such as food crops) outperform sedum (which needs shallower soil media) in evapotranspiration and the resulting benefits to the building and the microclimate around the roof (O’Carroll et al., 2023).<\/p>\n

When paired with the findings of another ENSCIMAN thesis, Assessing the Communication Network of a Budding Industry: Rooftop Urban Agriculture in Toronto, by Daphne Page (2014), we can hypothesize that sharing knowledge about rooftop food production would be a key factor in strengthening food production capacity in dense urban areas. The thesis examines civic food networks (CFNs) in relation to local food movements and emerging rooftop urban agricultural initiatives (Page, 2014). Page (2014) explores the knowledge-sharing potential that would help expand both the implementation and success of rooftop urban agriculture in Toronto and elsewhere. She conducted her research when rooftop farming was relatively new, and examples were scarce. Indeed, even today, sizable projects are still uncommon. Beyond the number of examples, rooftop growing still faces many challenges, from weight constraints that require engineered soil to finding buildings that are appropriate for, or adaptable to, production (Page, 2014). The need for effective knowledge sharing is palpable.<\/p>\n

In TMU’s School of Urban and Regional Planning, Jack Douglas Lawson’s (2021) thesis, A Pathway to Rooftops: A Feasibility Study of Green Roof Typologies at 105 Bond Street, explored what downtown Toronto would look like with green roofs added to existing buildings. His example, a 1920s building on the TMU campus, demonstrates the challenges of retrofits; yet, despite pre-existing mechanical systems, elevator penthouses, stair headhouses, skylights, and other obstructions, the thesis shows a feasible strategy (Lawson, 2021). The proposal includes “1) a holistic meeting space for students, faculty and school-side donors or stakeholders on its lower tier along with both (2) a native pollinator garden, and (3) research and food production beds on the upper tier” (Lawson, 2021, p. 11). Many well-known urban rooftop farms are located on retrofitted existing buildings, notably Gotham Greens and Brooklyn Grange in New York City (Page, 2014). The TMU Engineering roof, while purpose-built as a green roof, needed considerable modifications when the commitment was made to transform it from its original form as a field of flowers into a productive space. The constant presence of farmers, students, volunteers, and visitors is one of the biggest shifts to consider when designing productive roofs rather than other green roof types.<\/p>\n

What is potentially more exciting, as we teach the design and engineering aspects of productive green roofs, is the prospect of architects educating clients about the advantages of including a rooftop farm or allotment garden space in the program from the start. One example is the Garden Village project\u2014a Berkeley, California, student housing complex from 2017 \u2014designed with rooftop farms on every building (RAD Urban, n.d.).<\/p>\n

Design Proposals from TMU\u2019s Department of Architectural Science<\/h3>\n

Within the Department of Architectural Science, Bijan Ghazizadeh\u2019s (2015) master\u2019s thesis envisioned an elevated corridor that would create a Continuous Productive Urban Landscape (CPUL) in downtown Toronto. The proposal drew inspiration from the Continuous Productive Urban Landscape (CPUL) concept developed by Andr\u00e9 Viljoen and Katrin Bohn for London, UK (Viljoen, 2005; Viljoen & Bohn, 2009). In his thesis, The Gardiner SkyPark: Continuous Productive Urban Landscape as Infrastructure, Ghazizadeh (2015) proposed integrating pollinator gardens, linear park space, and productive community gardens into an elevated route through the city, giving urban residents access to growing spaces. The SkyPark would also create a car-free recreational and nature corridor for walking, jogging, and cycling, weaving through downtown Toronto, crossing the Gardiner Expressway, and ultimately terminating at Lake Ontario, while providing access to and views of garden spaces along the route (Ghazizadeh, 2015).<\/p>\n

\"Rendering
Productive urban landscape rendering (from Bijan Ghazizadeh’s thesis proposal).<\/figcaption><\/figure>\n

Eric Cheung’s (2025) TMU architecture master’s thesis, A Place for Urban Food Systems, envisions a food hub with a productive green roof to bring fresh local food to Scarborough, a borough of Toronto with comparatively limited access to farmers’ markets, community growing spaces, and urban farms. A central concern was providing access to culturally appropriate food (acceptability) to this largely immigrant population (Cheung, 2025). This adaptive reuse proposal addresses the recently abandoned elevated Scarborough Rapid Transit (Scarborough RT) rail line and its sizable metro and bus station. Cheung\u2019s proposal transforms the aging infrastructure running through Scarborough Centre into a linear elevated farm on the rail line, with a food hub below. The design proposal includes raised garden beds, trellised growing spaces, greenhouses on the elevated structure for year-round growing, an elevated walking path that traverses Scarborough’s urban core, and spaces for a farmers’ market, food processing, teaching kitchens, and food shops inside the former metro station (Cheung, 2025). Here, the rooftop farm component is part of a larger food hub system.<\/p>\n

\"Rendering
Proposed food hub in Scarborough rendering: Toronto showing the elevated productive space on a former rail line (from Eric Cheung’s thesis proposal).<\/figcaption><\/figure>\n

One of Cheung\u2019s (2025) central concerns was access to culturally appropriate food for the largely immigrant community the proposed food hub would serve. As in McElcheran\u2019s (2000) thesis, case studies demonstrated the feasibility of the design proposal. Examples of linear elevated gardens, including the Coul\u00e9e Verte Ren\u00e9-Dumont (also known as the Promenade Plant\u00e9e) in Paris and the High Line in New York City, showed how elevated urban infrastructure can be transformed into green, recreational space. La Cit\u00e9 Mara\u00eech\u00e8re in Romainville, just outside Paris, provided another model: a community teaching greenhouse integrated into a broader community food hub. Together, these examples informed a potentially iconic project intended to provide \u201cvisible and accessible opportunities for public participation in food systems in unexpected places\u201d (Cheung, 2025, p. 4).<\/p>\n

\"Greenhouse
Greenhouse and food hub “La Cit\u00e9 Mara\u00eech\u00e8re” in Romainville, near Paris, France (Photo by Joe Nasr).<\/figcaption><\/figure>\n

In TMU’s Department of Architectural Science, instructors crafted problems (design briefs) that included rooftop farms and other green roofs for their students to solve in their design studios.  The 2nd-year design studio has included a green roof for several years as part of library design projects. In fall 2025, the 2nd-year project design brief shifted to an even more food-focused project: a productive roof above a food hub.[3]<\/sup><\/a> From early design studios to graduate school thesis projects, students are learning about and promoting solutions to green our cities and expand local food production and access.<\/p>\n

IV – Rooftop Urban Farm at Toronto Metropolitan University<\/h2>\n

Beyond theoretical proposals, TMU students began putting urban food production into practice at an opportune moment. In 2011, two nutrition students, Catherine Lung and Stephanie Nishi, proposed growing vegetables on unused campus plots. With support from the Centre for Studies in Food Security and a design-build team of Department of Architectural Science students using recycled materials, Rye\u2019s HomeGrown was born. Led by Lung, the initiative expanded to nine ground-level sites across campus, ranging from a garden designed for campus preschoolers to a street-front garden near the Student Campus Centre showcasing crops from around the world. Following a small experimental plot on a green roof in 2013, the roofscape was transformed between 2014 and 2016 into a major expansion of Rye\u2019s HomeGrown.<\/p>\n

Today, TMU has rooftop growing spaces on two campus buildings, the Pringle roof on the Engineering building (mentioned above) and the podium roof of a recently built classroom and dormitory building\u2013the Daphne Cockwell Complex (DCC). The DCC roof includes tool storage and a large gathering space with a deployable sunshade on a large steel frame, enabling workshops, food events, and relief from the heat for farmers. Its sizable greenhouse has become a multi-functional space. The rooftops support food growing, distribution, community engagement through workshops and tours, food justice initiatives, and broader promotion of food literacy (Toronto Metropolitan University, 2019).<\/p>\n

The TMU Urban Farm and the CSFS partner in administering faculty- and graduate student-led research on the roofs. This “Living Lab” research on the roofs provides the seeds for understanding the impact food-producing roofs have on buildings, neighbourhoods, and cities. The TMU farm’s second rooftop on the DCC building shows how green roofs can serve as sustainability and amenity spaces, as well as productive growing spaces, opening up possibilities for stronger community engagement and more. These growing spaces can be an important part of strategies to increase food sovereignty, availability, and knowledge about food and culture (Living Lab, n.d.).<\/p>\n

The TMU Urban Farm hosts a hands-on Rooftop Farmer Training Program. It is also the site of Black Food Sovereignty initiatives on the roofs: The Harvest Collective and the Learning Circle bring to the Black faculty, staff, and student community the opportunity to enjoy the harvest of medicinal and food crops that are traditional to the African Diaspora and, until recently, difficult to find in Toronto. Another Farm project, the Indigenous Foodways program, “supports and celebrates traditional Indigenous ecological knowledge and ways of growing” (TMU Urban Farm, n.d.; Walker, 2026).<\/p>\n

 <\/p>\n

\"Toronto
Toronto Urban Farm at the Pringle roof on the Vari Engineering Building, Toronto Metropolitan University (Photo by Joe Nasr).<\/figcaption><\/figure>\n

Farming on the Pringle green roof changed what was possible to produce on a dense urban campus. During the first years, the Urban Farm Manager, Arlene Throness, and the Urban Farm Operations Coordinator, Jayne Miles, were hired to implement an ambitious transformation. They worked within the green roof’s soil-weight limitations, creating low walking paths for farmers and volunteers, enabling built-up deep garden beds for a variety of crops, and focusing on building rich soil for propagation.<\/p>\n

What began as a small student-led initiative grew through strong stewardship from the Centre for Studies in Food Security, university funding, and a strong relationship with University Business Services. The farm is now a formal department within food services, supported by CSFS, Facilities Management, and FEAS. The many food-growing and research initiatives that now take place at the two Urban Farm sites at TMU engage faculty, students, and the community. With attention to plant nutrition, crop rotation, rooftop weather conditions, soil health, and more, Throness and her team nurture a farm that produces 2,500 kg of food per year. Committed to food justice, one third of the farm’s crops are donated to nearby community organizations, one third is sold to the public, and one third is sold at a discount to students. The event space on the DCC roof was designed to help the University and local community learn about, celebrate, and share food together.<\/p>\n

One notable aspect of these two campus rooftop farms is that both were designed as green roofs from the start, although neither was initially intended as a food-producing space. The Engineering green roof, initially built with about four inches of soil and sown with flowers, needed some retrofitting when the farm was introduced. Over time, TMU added sinks for washing produce, irrigation hoses, repeated additions of soil and compost, adequate walking surfaces and barrier fencing that meets rooftop code conditions for human habitation. The DCC roof, always intended to be a habitable green roof, was redesigned for farming before the building was even completed, enabling an easy transformation from a leisure green space for students to a productive roof with an event space for the University and community. A parapet or fencing that meets safety regulations, along with clear walking paths that protect the roof membrane, are crucial for productive roofs. A tool shed, vegetable preparation area, shady space for gardeners, seed propagation areas, and an elevator to transport soil, plants, produce, and tools can further support success.<\/p>\n

The TMU Farm and the Pandemic<\/h3>\n

While TMU’s original rooftop farm shared and sold its produce in several ways, its contributions to programs alleviating food insecurity increased during the pandemic, showing the importance of local micro-farms in combating supply chain issues. The pandemic disrupted food distribution networks and exacerbated food insecurity among vulnerable populations. Some people were at risk if they left home to shop for food, so access to healthy, fresh food became a struggle. In Toronto, many non-profits responded to pandemic-exacerbated food insecurity, and the TMU rooftop farm helped.<\/p>\n

The rooftop farm donated fresh vegetables and herbs to the Moss Park Market, an initiative of Building Roots, a nearby Toronto non-profit that serves the Moss Park community, a neighbourhood with rent-geared-to-income apartments that was severely impacted by the pandemic. Volunteers at the Market assembled hundreds of food bags weekly at the Market’s small shipping-container “office.” Although much of the food bag content was purchased, the weekly bags also included fresh vegetables from local farmers and distributors, community gardens, local bakeries, and food grown on the TMU roof. After the pandemic, the TMU Urban Farm continued to contribute to these weekly food bags. In 2023, “Toronto Metropolitan University\u2019s rooftop urban farm donated 37 crates, totalling 436 lbs [197 kg] of ecologically grown produce over four months” (TMU Urban Farm, n.d.). Now, after the pandemic, the TMU Urban Farm uses a food distribution model that is designed to serve various communities; one third of the food distribution is donated to both students who are food insecure and Building Roots for its food distribution program, serving the community at large (Building Roots, 2021; Throness, 2023).<\/p>\n

V – Conclusion<\/h2>\n

As cities densify, ground-level space is at a premium. As cities densify, ground-level space is at a premium. Rooftop surfaces can provide additional space for food production, community activities, pollinator gardens, and other urban uses. From increasing biodiversity in cities to teaching food literacy and promoting cultural knowledge sharing through programs such as the Black Food Sovereignty initiatives and Indigenous Foodways at the TMU Urban Farm, growing where people live and work is a winning proposition. City initiatives such as the Green Roof Bylaws and financial incentive programs often help lead the way. Trends show that rooftop farms and growing spaces are increasing. Heat mitigation, additional recreation and community space, increased urban biodiversity, and, perhaps most important of all, aspects of food security are benefits we can reap from a robust green roof program. As we study more projects like this, the benefits should become increasingly evident.<\/p>\n

 <\/p>\n

 <\/p>\n

References<\/h2>\n

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  1. Specifically, courses such as Mark Gorgolewski's \"Architecture Option Studio: Creating Local Food Landscapes' and the course \"Creating the Productive City,\" taught both as a lecture course and design studio, addressed green roof design in its early years; GRHC focused primarily on green roofs more generally, not specifically on implementation. ↵<\/a><\/li>
  2. The team entry was called \u201cCliffside Village, Scarborough, Canada, despite higher investment and maintenance costs, higher-profile plants provide greater energy efficiency (particularly by \u201d (an urban agriculture strategy for strip mall developments). Team members: D. Feinmesser, Y. Mityuryayeva, T. Tso, and A. Hendershott. 2009. ↵<\/a><\/li>
  3. 2nd-year design studios in 2024 were led by Dr. Terri Peters; the 2025 food hub project is part of the 2nd-year design studio led by Dr. Dustin Valen. ↵<\/a><\/li><\/ol><\/div>","protected":false},"author":605,"menu_order":1,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":["june-komisar"],"pb_section_license":""},"chapter-type":[],"contributor":[78],"license":[],"class_list":["post-53","chapter","type-chapter","status-publish","hentry","contributor-june-komisar"],"part":47,"_links":{"self":[{"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/pressbooks\/v2\/chapters\/53","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/wp\/v2\/users\/605"}],"version-history":[{"count":1,"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/pressbooks\/v2\/chapters\/53\/revisions"}],"predecessor-version":[{"id":70,"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/pressbooks\/v2\/chapters\/53\/revisions\/70"}],"part":[{"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/pressbooks\/v2\/parts\/47"}],"metadata":[{"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/pressbooks\/v2\/chapters\/53\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/wp\/v2\/media?parent=53"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/pressbooks\/v2\/chapter-type?post=53"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/wp\/v2\/contributor?post=53"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.library.torontomu.ca\/rethinkingfoodsecurity\/wp-json\/wp\/v2\/license?post=53"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}