Living Wall!


The second wall is more complicated. First, we took the modules off from the wall, and we found the soils are very wet, especially the soils on the bottom of the wall. From the right picture, we can see how wet the living wall was. 2.jpg

Then we put the modules on the floor and clean them one by one. It was not very easy to wash those modules. Later we put soils back to those modules and planted new plants into modules.


All done! I learned about the ecosystem, planting design, and construction of living wall from this work.


Irrigation, Plant Density, and Weeds

Currently, the main portions of the modular green roof consist of two separate gardens: the succulent/xeric garden, and the prairie garden. At the start of the semester, we began to weed the succulent/xeric portions of the modular green roof. While the plants provide an attractive and native take on a traditional roof garden, (as with most plants) it takes a little while for them to establish. Meanwhile, irrigation provided to establish/maintain the garden as well as the low density of the plantings inevitably invited the weeds.

In addition to crab grass, we pulled a total of 453 weeds. Pictured below are some of the species we removed from the modules:





In addition, there was much cilantro from a previous planting that found its way into several of the modules (81 plants in total).


While this is a normal thing to expect for the low density plantings, adding density and lighter irrigation will minimize the weeds in the long term.

On the same day, we seeded several types of succulents and sedums, but many if them did not seem to establish (at least not yet). This being said, we learned that transplanting pre-potted plants or planting plugs is a more reliable way to ensure that new plants flourish. Since then, we have added many more plants to the modules, adding both to the density and appeal of the xeric/succulent garden.

Green Roof Experiential Learning Blog 2

And we also added new nine modules for growing proposed crops. In making the substrate and filling soils in the module, firstly we put a layer of substrate to fill the holes in the modules, and a square blanket was used to cover each modules on the top of substrates. And soils for growing vegetation are put on the top of blankets. The texture of substrate soils is coarse which can contribute to positive drainage within the modules and the texture of topsoil is finer than substrate soil and it is opulent with organic matter and water content.

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Then the most interesting part came! The transplanted and seed crops arrived, which included Arugula, Chives, Cilantro, Mint, Shallots and so on. Prof. Merrill helped us arrange the layout of different crop species and we took off the outside plastic packings of transplanted crops, burying the roots under the topsoil. Talking about the most difficult part, I think it is to install the irrigation system. I didn’t participate in that part, but I saw my teammates tried to connect the pipe with water source, cut the pipe according to the dimensions of modules, used nodes to connect pipes with chemical glues. Finally, four irrigation nozzles were set up around the crop modules. The nozzle radius is suitable for the site, but one full-nozzle should be replaced with half-nozzle.

Another type of plants we want to grow is succulent plant. So we also had a discussion about the appropriate species for roof planting and before that we each people had a suggestion list. I proposed 6 succulent plants, and I feel so honored that 4 of them had been chosen for growing on the roof, which include Sedum palmeri, Graptopetalum paraguayense, Opuntia cacanapa ‘Ellisiana’, and Euphorbia resinifera. Many other succulent plants are also proposed, such as Nolina macrocarpa, Hesperaloe parviflora, Sempervivum ‘Carmen’, and Agave colorata x parryi and so on. We spent much time on arranging and distributing them in a well-organized and good visual-effect way. We made the short plants as ground cover distributed around the tall plant in the center. The same species are arranged together forming a group.

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Green Roof Experiential Learning Blog 1

My name is Chenni Zhu, a third-year MLA student. On the first day we went up to the roof garden, what we were required to do is to remove invasive weeds and pick up mature fruits of some crops such as tomatoes, shallots in the nine modules on the ground. Then we need to weigh the fruits from crops and record the numbers. And I feel what a pity that most of crops grown on the roof in summer are dead for these one or two months. It may be due to the harsh weather which is too hot and dry without frequent precipitation in Texas.

So on the first day, we almost removed all of the weeds in the nine modules. However, what we saw in the next week surprised us that many weeds had grown up again in the modules due to a rain in that week. Thus, we had to weed them again to ensure there is no chance that these weeds would come up again. I have to say that the invasive weeds are really strong and capable of establishing themselves in prevailing conditions without manual intervention, while we should take more care to crops.

After weeding, we were required to discuss what kinds of crops are capable of living on the roof top and surviving well. A study about “Assessing Crop Viability for Agricultural Production on Extensive Green Roofs” provided us with some statistics about which crops are suitable for growing on the roof in Texas. The evidences showed that the strong survivors (80 %+) include Chives, Cilantro, Parsley, Thyme and Mint among transplants. Moreover, among direct seeded crops, strong survivors include Arugula, Garlic, Kale, and Shallots. On the other hand, every team member was required to provide a list of suitable crops for growing on roof. So based on the study and the information I collected, I think the Arugula, Chives, Cilantro, Mint, Shallots and Thyme are ideal crops surviving on the roof. After that, we discussed the final crop species and basic layout of them according to the visual effect of combination of crops, the different demands on water amount of different crops, and numbers of crops.

Below shows the later situation of some crops we grew on the roof. Most of them are in a good condition.

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Green Roof Learning Experience – Fall 2015 Blog 1 by Tiantian Lyu

Since it is not the first time for me to work on the green roof, I am more familiar with the working experience. In the summer 2015, I am lucky to have an opportunity to work on the green roof with Dr.Dvorak, which is the first time that I really understand what green roof really looks like. In the summer time, our major work is to design and layout the plants for living wall, which attracts me a lot and I really learned a lot from that experience.

In the fall, the work is a little bit different. A good growing environment is very important for the plants, the roof is overgrown with the weeds, so we need to do some weeding work first. It is hard to remove all the weeds, especially the smaller ones. After a rainy week, the weeds would grow again if we do not finish this step seriously. We need to know that every step is important for the plants.

After finish the weeding work, we need to select plants for the green roof. The following plants will be planted on the roof: Beargrass(25), Red Yucca(16), Mexican Sedum(13), Brakelights Red Yucca(12), Houseleek(12), Resin Spurge(8), Spineless Prickly Pear(8), Candelilla(8), Louisiana Yucca(8), Color Guard(4), Ghost Plant(4), Palmer’s Sedum(4), Mescal Ceniza Agave(4), Spider Agave(4). The reason why we choose these plants is that they can survive in the tough environment with more sunshine and less water.

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We also add 9 small blocks for the vegetable grow on the roof, for example, green onion, vanilla and so on. It is the first time for me grow vegetable in the green roof. In China, people always grow vegetables in the greenhouse, which could always provide constant temperature for vegetables and fruits. These vegetables we selected can also survive and grow well in the tough environment. With all these vegetables and plants, the green roof would be more colorful and alive.

Vegetables, Cable Ties, and Hose

November’s goals could not be pursued without Succulent Garden weed control.  A typical rooftop day sees the class split between weeding, collecting inventory/harvest data, or adjusting the irrigation system.  The Vegetable Garden’s rapid growth and lush color presented an image … Continue reading

Green Roof Food Productivity by Variety by Zane Pace

Our focus this month has been on harvesting the winter crops we planted last semester, and identifying our top performers. Plants were harvested continuously over several week period, sorted into marketable and non-market categories, and weighed for biomass. We generated data on establishment, survival, productivity, and marketability % for each crop. I was fortunate enough to be allowed to analyze the data myself, and to present our findings with Nicole Forbes at Texas A&M’s Student Research Week this year. Unfortunately, it turns out that I get maybe a little too into data analysis, and SRW posters only allow for the presentation of so much data, so a lot of the graphs and comparisons I churned out wound up not getting included. Fortunately, I know just where to present the bits I had to omit from the poster. Here.

First, I’ll give you a quick and dirty posterview (portmanteau of poster and overview, duh) to relate the general results. From a survival perspective, everything was pretty positive, with the exception of root crops like turnips and beets. Leafy greens and herbs are definitely viable for green roof production. Of those we were able to harvest for this data, Kale, Lettuce, and Parsley were the most productive. What I didn’t get to include, however, was the variation among different strains of these crops, which was considerable.

While we looked at the overall crops for their productivity, each of those includes several varieties, each of which produced at different levels and fared differently on the green roof. I can’t be sure why this was the case, but the intracrop productivity splits were apparent enough that I wanted to investigate them. I did so by charting the relative contributions to a crop’s total marketable biomass by each variety, or varietal market share.

Lettuce provides a nice starting point, because it displayed a very even varietal split. With only two varieties, it is also the most basic case. We planted the same number of both Butterhead and Romaine lettuce, and establishment was identical for each. They each produced about the same amount of marketable biomass too, so the split is almost 50/50. This is expected.


Parsley getting a little less even

Parsley exhibited a slightly different share split. 3 parsley varieties were planted, including Italian Plain, Curly Leaf, and Italian Giant. Of these, the Italian plain produced 50% of the marketable biomass, while curly leaf and Italian giant generated 28 and 22 percent, respectively. I don’t have an explanation for this difference, but it is a significant split relative to that seen in lettuce.

What is Red Russian Kale doing with its life?

The Kale is the one I really want to discuss, however, because it has an extreme varietal split. We planted Beira, Toscano, and Red Russian kale varieties. All of them grew and survived at high rates. However, beira kale produced a full 73% of the marketable kale biomass from the roof, while red Russian accounted for only 5. Toscano was 22%. Part of this split is due to differences in leaf size and shape among the varieties. Beira grows wide, large leaves more similar to those of lettuce, while red Russian and toscano produce the long, slender leave you might typically associate with kale. Hence, Beira leaves just account for more biomass. However, the splits were further driven by flaws in the other varieties. Only 28% of the red Russian was marketable, compared to 73% for beira and 98 for toscano. The reason for most of this was bugs. Red Russian kale leaves that were otherwise perfectly fine had to be rejected due to the loads of aphids they attracted. Aphids that didn’t appear on any other plants on the roof. I have no idea why these bugs seem to love red russian kale alone, but they seriously compromised large proportions of an otherwise fine harvest, and should be accounted for in any future green roof farming projects.

Green Roof Experiential Learning – Spring 2015 Blog 2 by Nicole Forbes

Spring is here (well as close as you can get to spring here in Texas) and with it has come a revival of plant and crop life! The mint has come back with a vengeance and some of the other plants that were looking dreary are greener than ever!

Nicole blog 2 photo 1

Zane and I presented our green roof crop research at Student Research Week the week after Spring Break. It was an awesome and rewarding experience. It gave me experience both in poster making and presenting research to a group of judges, I hope this experience will help me in future research presentations.

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Other than Student Research Week, we have continued harvesting and have begun to take down the living walls. There is not too much to report this time, but we will be redesigning the living walls and planting new crops and plants. I will also be looking after the crops over the summer after I get back from a month trip to Costa Rica! I’m looking forward to finishing the semester out!

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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!

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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

Camera mount, temperature control, and water damage – by Logan Gerber-Chavez

March 26


Greenroof East

Greenroof East

Greenroof West

Greenroof West

We mounted the camera and had to adjust the angle so now the camera is stable and won’t fall over in the wind.

Andrew Kirkpatrick and Kat Cobb mounting the East camera and adjusting the angle

Andrew Kirkpatrick and Kat Cobb mounting the East camera and adjusting the angle

Today we also figured out a placement for the control temperature probe on the west side.

Kathryn Westerman, Logan Gerber-Chavez, Dr. Conlee, Kat Cobb, Andrew Kirkpatrick, Robby Chilton, and Lauren Siedensticker discussing the location of the West side control temperature probe

Kathryn Westerman, Logan Gerber-Chavez, Dr. Conlee, Kat Cobb, Andrew Kirkpatrick, Robby Chilton, and Lauren Siedensticker discussing the location of the West side control temperature probe

Kat Cobb installing the West control temperature probe

Kat Cobb installing the West control temperature probe

We were looking at the data coming in and nothing on the east side was working so we opened the wiring box under the tripod to check it and found water had somehow gotten in and started to rust the equipment.

East side wiring box was damaged by standing water

East side wiring box was damaged by standing water


April 2


Greenroof East

Greenroof East

Greenroof West

Greenroof West

We spent today trying to clean up the damaged wiring box that we discovered with water last week and figure out how to restore it and order the new parts.

We also wired the control on the west side.

West side instrumentation wiring

West side instrumentation wiring


April 9


Greenroof East

Greenroof East

Greenroof West

Greenroof West

We spent the day replacing the wiring in the damaged east side box.

Kathryn Westerman collecting replacement wire to rewire East side box

Kathryn Westerman collecting replacement wire to rewire East side box

Lauren Siedensticker rewiring East side box

Lauren Siedensticker rewiring East side box