Green Roof Experiential Learning – Spring 2015 Blog 1 by Nicole Forbes

I’m back again for my second semester working on the Langford Green Roof Project! It has been an awesome experience to be a part of this while watching the plants grow and new ideas transform. I really have not got to do too much yet this semester as weather has been bad and I was in Costa Rica for a week, but weather is supposed to be getting better so hopefully next blog I will have more to report. Zane and I will also be presenting a poster at Student Research Week after Spring Break which should be a very rewarding experience. I will be sure to get pictures for my next blog!

My first day back on the roof was really cool to see. I assumed with the weather being so cold over the winter break that most of the plants would not fare so well but I was thankfully mistaken. Many of the plants grew very well on the roof modules. The lettuces and herbs did very well (except for the bell pepper basil, all of that died out for some reason), especially the parsley. I think a roof of parsley and mint would grow exceptionally well here in Texas year round and would create a beautiful green garden that can be used for cooking also! The living wall was disappointing, however. Mostly everything died out or is looking very bleak, with exception to the garlic and shallots which seem to be doing fairly well. I am hoping some of the mint recovers and grows back, but only time will tell.

It was also very interesting to see how some crops did well in certain spots, while in others they did not survive. I saw this with the turnips, beets and red kitten spinach. There are many reasons as to why this occurred, but I lean more towards three explanations:

  1. Irrigation – Something is going on with the irrigation system and plants are being watered unevenly
  2. Sunlight – Different spots on the roof get different amounts of sunlight which is affecting growth rates
  3. Nutrition – Some spots received more fertilizer than others

As we approach the planting season for summer crops, these are the crops that I think we should plant:

  1. Herbs – I think we should plant more of the herbs that did well (parsley and mint) and I think we should also try cilantro and dill, both of which grow very well at the Howdy Farm on campus and I would be curious to see if they do well on the roof also.
  2. Broccoli – I know we planted some in the fall but I am curious to see if it would do better in the spring as broccoli likes direct sunlight (which there is plenty of on the roof) and has a moderate maturity rate.
  3. Cabbage – With how well the lettuces did, I really would like to see how cabbage fairs. However, cabbage has a much longer maturity rate so I am not sure if that will affect the decision.
  4. Bush beans – These mature quickly and I think they would be really cool to try and grow.
  5. Lettuce and spinach – These did well so I think we should try them again in the spring to see if they grow well during this time also.


Below are pictures from the first day back on the roof!

Nicole photo 1Nicole photo 2

Nicole photo 3



Green Roof Experiential Learning – Spring 2015 Blog 1 by Martha Todd

The first week of class we began harvesting and weighing vegetables that were growing in modules on the roof. I was surprised at how healthy and plentiful all the vegetables were. There was a variety of crops too, including Italian parsley, cilantro, spinach, and even turnips! It was interesting to notice though how the crops on the ground had done so well; however, the plants on the wall were all dead with an unknown specific cause. It is possible that the plants on the wall could come back after winter but little growth was noticed throughout the weeks even when we trimmed the ends of the plants in order to spur new growth. It could also be due to the restricted space the plants are given as they are seated in small pockets along the roofs walls or due to a lack of or surplus of moisture. We hope that over the semester to identify what the problem is and correct it in order to ensure better and healthier plants that can live year round.

Now the planning remains as to what plants should replace those that are dead. After an excellent presentation by Professor Dvorak, who introduced me to the famous botanist Patrick Blanc, I could visualize what our goal was on the top of the Langford Architecture building. We need to find plants that are evergreens and can live all year round and find crops to grow on the modules that rest on the ground of the roof as opposed to the other plants that grow vertically along the wall in pockets. Some of the edibles I would like to plant in the ground modules are rosemary, tomatoes, bell peppers, basil, and cilantro.

Finally, there is one more side to the project and that is using sensors to track some of the plant’s growth and how they are doing in the given living conditions. Dr. Conlee and his students came and together we programmed sensors that can sit in the soil with plants that will be growing on the wall. Eventually we hope that this data will help the class to make conclusions on the influence of a green roof on albedo levels as well as the amount of long wave and short wave energy that is being transmitted

Green Roof Experiential Learning – Spring 2015 Blog 1 by Ivan Mendoza

Howdy. My name is Ivan Mendoza. I’m an undergraduate senior in Horticulture. I am taking this greenroof experimental course so that I can see which plant species thrive in this area of Texas on green roofs. As a perspective landscape architecture student, I’m hoping I can use the knowledge I gain from this course and hopefully apply it to future landscape and commercial designs. When we started this spring semester, we had edibles in place on modules which were planted last spring.  We also have 3 living walls in place. The first living wall has succulents and sedges in place, the second has strawberries, mints with some other perennials, and the third has a mixture of perennials. The first day we recorded inventory of the number of edibles for each species that was still alive on each module. The majority of the edibles that were planted last spring did fairly well, except for Basil (Bell Pepper), Chinese cabbage (Rubicon), Radish (Easter Egg), Turnips (Hakurei) and a couple of varieties of other species. The growth size of the edibles that did well varied across the modules due to external factors (light, water, wind, etc.)  Following, we harvested the edibles to have them regrow new foliage and recorded the data.

Ivan photo 1

Ivan photo 2


We have also cut any flowers that have been growing on the edibles so that they focus their energy more on growing. Slow release fertilizer has also been applied on these edibles which has helped them grow as well. We have been focusing on which edibles we are going to plant later this spring as well as the perennials we need to replace on the living walls (especially living wall 3). We notice that rosemarinus officinalis, ficus pumila, and artemesia “powis castle” are some the species regenerating growth on living wall 3. We have been trying to figure out why the other perennials on living wall 3 have not done so well. We do not have any information collected to try and narrow down the problem. We will come up with a list of edibles and perennials to plant on the modules on the roof and on the living walls.  This class has been very interesting so far and I am excited to see what our proposed plant species do in the future.

Living Wall 3

Ivan photo 3


Living Wall 2

Ivan photo 4 _ living wall 1


Living Wall 1

Ivan photo 5

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.

Original post: