Green Roofs In Action by Zane Pace

Green Roofs In Action

If you’ve never seen a green roof, the concept can seem bizarre at first. When I explain green roofs to people, it can take them a while to understand that I am talking about actual vegetation on a rooftop, and not just using green as a stand-in for sustainable. So, for my first blog entry, I thought I would share some photos from my sustainable communities Germany study abroad. Germany is the home of modern green roof technology, and it is there that we can gain an idea of what green roofs look like in practice, rather than theory.

For comparison’s sake, here is our experimental green roof on top of the Langford architecture building:


One institution that was important in the development of green roofs in Germany is the ufaFabrik culture center in Berlin. Today’s ufaFabrik developed when young squatters took over the former UFA-Film copy center in 1979 and turned it into a center for developing alternative forms of work and living. UfaFabrik was then the site for various cultural, social, and ecological experiments, “based on the vision of a meaningful integration of the areas of living and working with culture, creativity, and community.” One of these ecological experiments was with green roofs, which now top most of the buildings on the site. These roofs are older than most green roofs you can see today, and provide a glimpse of how they look and age.


This is a picture of the café at the ufaFabrik, to show you what a green roofed building looks like from the ground. It’s sort of like a normal building, but with hair. Hair that cleans the local atmosphere, moderates local temperatures, reduces stormwater runoff, and lowers energy bills, among other things.


Standing on a green roof, you can begin to see how their widespread adoption could increase the amount of functional space on a city. On a sunny day, this roof looks like as nice a place as any to lay in the sun and read a book.

Not all green roofs need to be accessible to people, nor flat. The next two photographs show other roofs from ufaFabrik that highlight variations in the technology. As you can see, the roof on the left combines a green roof with a system of solar panels. While the panels would seem to conflict with the goal of growing plants, they in fact provide habitat for shade-tolerant species on the roof, increasing the biodiversity of the system. The energy produced from the panels combined with the savings from the green roof make this building extremely energy efficient.


The roof in the right picture is more like what you might imagine installing on your typical American residential home. As you can see, sloped green roofs are possible as well, and not unattractive.

Outside of ufaFabrik, we can see green roof technology applied to a number of different buildings, and consider how the nature of the green roof changes with the use of the building.

From the bell tower of the cathedral in Cologne, one can see a number of different buildings with green roofs.


This is a Maritim hotel building on the Rhine. The roof is a simple extensive system, but it does incorporate some ornamentals for hotel guests to look at. This, and the institutional building pictured below, provide an idea of how purely extensive green roofs often used on large facilities look. These are used primarily for their thermal insulation, ecological benefits, and long lifespan.


The third roof is in the courtyard of an office building, and, while inaccessible, we can see trees growing on it. Obviously, whoever commissioned this roof is aware that views of green space increase worker productivity and well-being.


Outside of Germany, I’ve seen other examples of green roofs in action as well.

When we visited Amsterdam, we used AirBnB to stay in an apartment located in a central Amsterdam development known as the Funenpark. The Funenpark is composed of multi-story apartment buildings surrounding a central, pedestrian-only park. Here is the view from the middle of the Funenpark.


The buildings create a noise barrier around the park, such that as soon as you cross into the funenpark the sirens and horns of Amsterdam traffic die away completely, replaced by birdsong and rustling leaves. There’s a school in the middle of the park, and Sundays see residents line picnic tables twenty on end for a community dinner. It is unlike anywhere I have ever been. It gives us an idea of how we can structure livable, green, high-density developments, and of how to incorporate green roofs into apartment buildings. Several of the buildings in the Funenpark feature greenroofs, and like the one pictured here. As you can see, patios from the upper story apartments are cut into the greenroof, allowing those residents access from their apartments.


My last example of a green roof in action is a somewhat different application from the others that we have seen. I found it last spring while wandering around Porto, Portugal. From one angle of approach, you can walk on top of it and not even realize you’re standing on a structure.


From a different angle, however, it becomes apparent that this seeming park in a square is in fact a small shopping center with a green roof on top.


This is one of the things that inspired me to look into green roofs, as it demonstrates how much they can do to improve our cities. Just by greening the roof, Porto was able to develop this square into both a beautiful greenspace and a functional commercial center. Ultimately, that’s what green roofs are about- not having to choose between enjoying the benefits of development and enjoying the benefits of nature.

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Green Roofs & Urban Agriculture by Zane Pace

Blog 2: Green Roofs & Urban Agriculture

During the past few weeks we’ve planted a variety of food crops on various aspects of our green roof and wall systems. As such, I wanted use this blog entry to talk a little bit about the role green roofs could play in a system of urban food production, as well as highlight the growing importance of the city as a food producer.

Traditionally, cities have relied on their rural surroundings for their food. Not a lot of space in your typical human city has historically been dedicated to food production. As we come to terms with 21st century realities like climate change, resource limitations, and the urbanization of the global population, it becomes apparent that cities are going to need to produce more of their own food. Shifting food production into the cities will reduce costs associated with transporting, handling, and storing food, and also reduce waste. Reducing food wastage is going to be critical in forging a sustainable society. According to the FAO1, the carbon footprint of food wastage would rank it as the third largest CO2 emitter globally after the US and China, and it consumes an amount of freshwater equivalent to the discharge of the Volga. For the sake of visualization, here’s a picture of the Volga:

Food wastage is like this river, except made of half-eaten chick-fil-a sandwiches.

The United States is a big contributor to food waste, as the USDA reported that 31 % of the nation’s available food supply went uneaten in 2010, good for a loss of 133 billion pounds of food, $161.6 billion, and 1,249 calories per capita per day2. That’s the equivalent of an original sandwich from Chick-fil-A with a large fries, medium coke, and a side of buttermilk ranch sauce, for everyone in America, every day of the year.

Imagine if we actually ate all the food we ordered in this country

Imagine if we actually ate all the food we ordered in this country. Ugh.

What might a food producing green roof in the city look like, though? Or better yet, what role could a green roof play as a component in a larger system of urban food production? Looking at Brooklyn Grange, a rooftop farm in New York City, we can see the answer to the first question.

Retrieved from

The Grange has two farms totaling two and a half acres of space that produce 50,000 lbs. of vegetables each year. This is a good start, but vegetables aren’t enough to feed a city, nor can every roof be converted to an intensive vegetable garden. Thus, to answer the second question, I want to think about other concepts that can complement green roofs in urban agriculture.

One is simply converting existing green, public space to agricultural production. The city of Trier, Germany has undertaken a highly successful experiment in this field, creating what it calls an Edible City. The castle in the center of town is a large public space surrounded by parks, and now much of this park is devoted to producing food free to the public, including vegetables, herbs, and chickens. While there were concerns going in about vandalism and over-use by the public, but these were simply never borne out. People seem to respect this use of public space, and the project has increased in popularity every year. The crops are tended by formerly homeless or long-term unemployed individuals who use the program to develop employment skills and find work, which the majority of program participants had done when we visited. You can see how Trier looks below.


This public production of food could do a lot to reduce food wastage by increasing respect for and awareness of food production in individuals who would normally never think twice about where or how their food is produced.

There are also novel technologies that could be paired with green roofs for food production. Aquaponics is a form of production that grows both produce and fish. While it requires a green house, thus precluding its use in the same structure as a green roof, it produces large quantities of fish and produce with limited inputs. The fish provide fertilizer and carbon dioxide for the plants, while the plants provide nutrients and oxygen for the fish. A green roof built for farming could incorporate similar water recycling mechanisms to reduce the inputs needed. Regardless, aquaponics, vertical gardening, keyhole gardening, green roofs, and other new systems could combine some day to produce a meaningful amount of food within the city.

In addition to farming produce on a green roof, there is no reason why simple extensive systems couldn’t be used to raise livestock. While large animals obviously present challenges, green roofs seem like ideal environments to raise smaller stock like chickens. Lay-hens on such a roof could produce free-range, all natural eggs in the city, and converting rooftops to small scale meat production could lessen our reliance on industrial scale meat production with all of its environmental and ethical concerns. This is probably just the organic chicken farmer in me, but I think it’s possible.

There are, of course, other technologies and forms of production that could complement green roofs means of producing food in cities. Many of these are focused on producing as much food as possible in as little horizontal space as possible, which is obviously an objective of urban agriculture. Where green roofs present a novel opportunity is in converting existing nonfunctional space into productive space. Together, these technologies could reinvent our cities as leading centers of innovative, sustainable food production.

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Plant Check on the Roof by Zane Pace

Blog 3: Plant Check-In on the Roof

This month we focused primarily on keeping track of how the various food crops we have planted have done on the roof and wall systems we cultivated. Given that this is an experimental planting, we do not expect every species to be successful. Hopefully we can ascertain which species will be viable for green roof production in the future from this planting. As such, I wanted to share my impressions of how the crops we’ve planted on the green roof and living wall have done thus far as we come to the end of the semester.

We’ll start with the green roof, which I have to say is very successful overall. Many of the transplants survived and look healthy, and most of the seedlings have germinated into promising little sprouts. The transplants include primarily strawberry, mint, parsley, and cilantro varietals. Here, you can see them at planting and today (12/7):roof1IMG_0496

As you can see, there has been substantial growth, and to our excitement it looks like some plants are doing quite well. The best performers are the herbs: parsley, cilantro, thyme, and chives. The strawberries and mint are a different story. While the majority of both crops are still alive, they seem to be struggling and just don’t look as happy as the herbs.

From seed, we planted the green roof with lettuce, kale, arugula, spinach, garlic, radishes, turnips, shallots, and perhaps a couple others. Most of these are doing fairly well, with the exception of the turnips and perhaps radishes. All of the seeds planted have germinated into seedlings in a majority of the modules, as seen in the kale and arugula modules pictured below.


There are some differences between varietals as well, as the Beira Kale we planted has fallen prey to some critter that has no interest in the Red Russian Kale pictured above. There is also variation in health among species and varietals across the modules. This seems due to sun/shade discrepancies resulting from all the walls surrounding the roof. Generally, the more southerly modules look less vibrant than others. Given how early in their life cycle it is for many of these crops, it is too early to determine which will produce the best, but overall I am excited with the results thus far.

The living wall we planted primarily with transplants, with some direct seeding to compare. The species included are strawberry, mint, lettuce, collards, garlic, shallots, and some random ones we had left over. Below you can see a picture of the wall midway through planting. This system is designed so that each plant has its own pouch of soil, which is then inserted into a pocket on the wall. The plants are confined to their pouches, which are watered by dip irrigation. As I see it, this design poses several problems, which is probably why the plants on this wall do not look great today.


First, the pocket system puts a lot of stress on the plants. Since the pockets are directly under one another, and not offset, irrigation from the drip system seldom affects more than the row directly underneath it. I pulled many dry pockets off the wall when we were preparing to plant. Furthermore, the pockets contain a limited amount of soil for the plants to grow in, restricting their capacity for growth. Finally, each pocket has a skirt, and this often interferes with sunlight reaching the plant in the pocket below. I had to pull several plants out from behind the skirt and back into the sun during our species count. Below, you can see an example of a pocket, with the irrigation line and the skirt from the pocket above it.


For now, many of the plants on the wall are still alive, but few are doing great. The mint and strawberries look to be struggling, while it’s hard to tell on the lettuce transplants. Nothing seems to have grown much since being up there. Flaws in the roof system aside, it will be interesting to see how the plants turn out in the spring. Hopefully, we can demonstrate that food can be grown on walls as well as roofs.

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Vela, Juan Carlos_Blog 3_Photo 1_LAND 685_Fall 2014

Since the use of fruit and vegetable crops on one of the green roofs seemed like a good idea, my classmates and I also thought it would be interesting to see how such crops would perform on a living wall. As with the green roof, various types and varieties of crops were used, as well as different growing techniques. Due to the living wall system consisting of pockets, all transplanted plants had to be wrapped in cloths and then inserted into each pocket. For plants that were directly seeded, we prepared pockets of soil in advance and then inserted the seeds by hand.

Unlike the green roof that was planted prior to this, a few of the plants on the wall do not seem to show much promise and water intake appears to be an issue. Weekly observations have indicated a slight decline in many of the plant species we selected, particularly some varieties of mint. Should these conditions continue, it is likely that many of the plants will have to be replaced. However, since these projects are primarily for research purposes, any results or data collected are helpful in understanding how these systems work and how our current methods and techniques can be improved.

Vela, Juan Carlos_Blog 3_Photo 3_LAND 685_Fall 2014Vela, Juan Carlos_Blog 3_Photo 2_LAND 685_Fall 2014




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Vela, Juan Carlos_Blog 2_Photo 2_LAND 685_Fall 2014

After collecting all the inventory data that was needed, my classmates and I spent a couple weeks rearranging plant modules and removing any unwanted plants from them. Once we had removed all plants from the unsatisfactory modules, we began brainstorming ideas for what kinds of plants could be used as replacements. The consensus was that we would be experimenting with vegetable and fruit crops to determine whether or not they would thrive and adapt on a rooftop setting. Some of the crops we chose to work with included different varieties of strawberries, lettuce, kale, and garlic. Many of these crops were selected for their hardiness, but some were chosen for the sake of experimentation.

Vela, Juan Carlos_Blog 2_Photo 1_LAND 685_Fall 2014While some of the plants were simply transplanted, others were directly seeded. This was done to determine which method would yield better results. Weekly observations have indicated that both methods are successful and many of the plants have begun to show promise. If these results continue, we may actually be able to harvest some of the crops within the next couple of months or so.




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Texas A&M Green Roof and Living Wall Experiential Learning Projects (Fall 2014) – Blog 1 by Jace Vela

Texas A&M Green Roof and Living Wall Experiential Learning Projects (Fall 2014) – Blog 1

Vela, Juan Carlos_Blog 1_Photo 1_LAND 685_Fall 2014

For the first few weeks of the green roof and living wall experiential learning class, we concentrated our efforts on inventorying existing plants on two separate green roof systems. These systems had already been established prior to this semester and our objective was to determine which plants had survived and which ones had not. Each student was given a set of plant lists, which were then used to identify and record the condition of the plants that had originally been planted in each module (nine total for each system). We also began removing any weeds from each module, which were then identified and tallied. This was done so that we could have a better idea as to what types of weeds were invading each plant module and to determine their overall invasiveness and potential threat to the remaining plants.

Once all surviving plants had been accounted for, we began discussing the possibility of placing the best modules under one green roof system. This of course meant that we would have to relocate and replant several modules. Relocating the modules took about two weeks to complete, but once the task was done, we proceeded to remove the plants (if any) from those modules which had been deemed as unsatisfactory, as well as brainstorm ideas for what could be planted in those modules.

Vela, Juan Carlos_Blog 1_Photo 2_LAND 685_Fall 2014Vela, Juan Carlos_Blog 1_Photo 3_LAND 685_Fall 2014

Transplant the green roof and living wall#2 by Siyu Yu

Transplant the green roof and living wall

This semester we replanted 9 modular of the green roof and living wall #1 with vegetation and crops aimed at research on vegetation establishment on a modular green roof and living wall in south-central Texas. We took off the succulent, bahia grass, and so forth. After that we planted strawberry, mint and lettuce, etc.

  1. Green Roof


Fig.1 Replant the green roof with vegetation.

We try Lettuce, Parsley, Cilantro, Mint, Strawberry, Spinach, Mustard, Beets, Cauliflower, Kohlrabi, Radish, Swiss, chard, Onion, Garlic, etc. Mint looks pretty good, but herbs needs more attention after we transplanted on October, 22.


Fig.2 The growth status of transplant vegetation.

  1. Living wall

We try Mint, Strawberry and Lettuce on the living wall. The vegetation grows very well, we will do plant count next week.


Fig.3 Transplant living wall #1 with lettuce, mint and strawberry.

Plant records of living wall #2 by Siyu Yu

Plant records of living wall #2

Our group planned to replant the live wall with crops and vegetation, so we took off the plants of living wall # 2 and took records of the plants on October 20, the picture of the living wall #2 is as followed (Fig.1).


Fig.1 The comparison of plants and vegetation display of live wall # 2.


As the picture shows that there are still lots of plants are alive without any fertilizer for almost one year. Moreover, many plants ‘roots are very moisture (Fig.2). So they can be widely used in green wall technology.


Fig. 2 The roots of plants

Potential species for the good crop green wall by Siyu Yu

  1. Green Roof and Green Wall

Building roofs that covered with plants is green roofs. It can be divided into two major categories, one is intensive green roof, and the other is extensive green roof. The main differences of these two types green roofs are the growth substrate depth and the requirement of the roof structural reinforcement. (Oberndorfer et al., 2007) Our research focuses on the extensive green roofs, whose growth substrate depth less that 20cm and require little maintenance. Plant selection is the main task to build up a sustainable green roof, especially subtropical climates, like south-central Texas, which encounter with drought and heat every year. We need crops that can be water tolerant and unirrigated.

Building wall that covered with vegetation is green wall, which holds a growing medium and soils. It can be categorized according to the type of growth media used: loose media, mat media, and structural media. The planting forms are watt pocket, square pocket and independent pocket(Fig.1).


watt pocket


square pocket


independent pocket

Fig.1 Three planting forms.



  1. Crop selection

There are lots of crops can be taken into research, green leafs are creamy green leafy lettuce, arugula, purple cabbage; Spices, Thai basil, sweet basil, parsley, mint, chives; Vegetables are tomatoes, strawberries, cucumbers, broccoli.

As it suggested in the list, the strawberry and mint are the main crops of this research.


  • Strawberry
  • Green roof economic of strawberry

There is a strawberry garden case in Shenzhen, China. Based on the test result, the temperature on the “green roof” is 12 Celsius lower than the surrounding concrete roof, and the average temperature of attic is approximately 4~7 Celsius. The strawberry is evergreen with many leaves. It does not need as much soil as most plants, about 120Kg per square meter. And strawberry likes humidity environment and has strong water absorption ability, which totally satisfies the need of green roof. What is more, a strawberry garden of 7000square feet produces strawberries about 4000 pounds annually. The market price for strawberries is $1.5 per pound, which produces an annual profit of $6000.


  • Strawberry Fields Green Roof and Garden

This green roof sits atop an office building in downtown Vancouver. I helped design and build this roof in 2009 as a green oasis for the company employees and a demonstration of green roof technology for other businesses in the area. The roof was dubbed Strawberry Fields because of the abundance of strawberries planted among the sedums.




  • Mint (Mentha)

The leaf, fresh or dried, is the culinary source of mint. Fresh mint is usually preferred over dried mint when storage of the mint is not a problem.



Oberndorfer, E., J. Lundholm, B. Bass, R. R. Coffman, H. Doshi, N. Dunnett, S. Gaffin,

  1. Kohler, K. K. Y. Liu, and B. Rowe. 2007. Green roofs as urban ecosystems:

Ecological structures, functions, and services. BioScience 57: 823-833.