Before the course began this semester, I had a brief view of the green roof and the living wall from the knowledge I acquired from construction classes. The benefits of them are clear and the vision of future city with living walls and green roof is fascinating. That is why I wanted to take this course: to get a closer look at this ‘new weapon’ in a landscape architect’s armory to learn its weakness and challenges.
In this semester, the main project is on the extensive green roofs. There are 3 different planting systems on the roof, which are prairie, succulent garden, and urban agriculture. The learning process combines with these parts: labeling the plants, doing health rating of plants, eliminating weeds, planting new plants, and fixing and maintaining the irrigation system.
Texas is such a hard place to utilize roofs as planting spaces. Due to extreme climate change in this area, the plants on the succulent garden suffer from sudden change of temperature. The plant palette is the main challenge we have when we want to design a roof garden. The process of selecting and testing proper plants is time consuming and in need of great effort of protecting the research area. During this semester, I witnessed the flourish of plants we assumed dying, and the decline of plants due to carelessness of construction workers on the roof. The experience reminds me of the importance of patience and carefulness in learning.
The labeling and evaluating process have enhanced my knowledge of plant species, especially succulent plants. Meanwhile, the process of organizing data of plant evaluation took me to have a quick look at how the research work is done in landscape architecture area. As the Texas native species grow very well when spring comes, I have a better understanding of choosing plant in my future design in Texas. In addition, the recognition of weeds will also benefit my future career. The overall experience has given me a deeper understanding of the suitable character of plants on the roof. At the end of this semester, the urban agriculture side have new plants with rapid growth. The squish and eggplant grew faster than I imagined. It is always pleasant to watch these cheerful growth of the plants you put your effort in and the lovely looks of these succulent plants.
Last but not the least, the course involving irrigation of roof also gave me the knowledge of how to build a irrigation system on the roof and how to maintain it. The hazardous climate in winter causes the water left in irrigation pipes to freeze, which will break the PVC pipes. As a solution, we need to pull out the water in pipes before the coldest days come, or use soft pipes which have flexibility when the water freezes to reduce damage.
This spring I teamed up with fellow MLA student Zhihan to help maintain the green roof. At the beginning of the semester we completed the plant list based on former student’s work. The Langford A Building green roof, set up by previous students, is divided into 3 sections: edible palnts, succulents, and prairie. Each of us also recommended 3 new succulent species to the plant list. Then we went to the rooftop and planted these new species. Afterwards we did the evaluation on the plants for Prof. Dvorak’s research. We also did weeding for the modules and helped set up the irrigation system for the edible section.
Helping with the edible garden. Photo credit: Zhihan Tao
What’s different from the regular class
First I learn about several green roof plants. I took HORT courses before and there is no introduction to specific green roof plants. This is because there is not enough research conducted. With Prof. Dvorak’s work we are learning what plant species are good for green roof in Texas.
Get my hands dirty. I planted the plants in modules and did weeding. Planting plants is more fun than learning their characteristics in regular class. For planting the plants in modules, I learned from Prof. Dvorak that the same species should be planted in one module for observation and demonstration purposes.
Set up irrigation system. We helped Dr. Merrill set up the irrigation system with his edible plants section. We learned how to draw irrigation plan in the construction course, it’s really fun to take actions and build the system from the scratch like cutting pipes. Seeing the nozzles sprinkling is a very beautiful moment.
Photo credit: Zhihan Tao
Overall, working on the rooftop is a very worthy experience in the MLA program.
For the fabric living wall, we just did slight changes. We removed the previous plants which are already gone and replaced with new species which may be more appropriate for the fabric living wall system. Most part of the system is going very well.
The system has its irrigation line on top of each row and the fabric can easily absorb water which is a good aspect for irrigation. Each fabric pocket can hold a plant. We need to carefully wrap the plants and give them enough soil for them to grow. The design is quite easy for planting.
Studies showed that living walls can bring thermal benefits and increase energy efficiency. Still, we need to find out the most appropriate species for living wall and create the best living environment for the plants. I think that’s the meaning of the attempts we are doing now. Hope all the effort we have made this year will show a great result in the next blooming season!!!
We also worked on living walls. First, we removed the old modules from the wall. We noticed that the old environment created a great living surroundings for small insects which increased the eco-biodiversity.
After taking all the modules off the wall, we cleaned them in prepared for new plants. We filled the module with soil(half volume of the module size) and planting the plants. After put fertilizer on top layers of each module, we filled the module with extra soil. At last, we settled 100 modules.
For the whole semester, we did a lot work on the roof. At the beginning, we got rid of the weeds of the planters on the floor and the modules on the wall. Some plants are growing well, although some weeds were there. We planted several fruits, like tomato, on the left side of the roof. So far, they are healthy and pretty.
Two weeks later, we started to make some new modules. Base the amount of the soils, we decided to make 18 modules and separated them into 2 groups first. It was hard to bring such a lot of soil to the rooftop, but eventually, we did it.
We aligned the modules into two groups by 3×3. Then we filled gravels and soils with different percentage into those modules, for the future research.
I learned how to prepare for planting, it is good to know how many pounds of soils we need/have before we getting started. I have also learned the process of process of preparing and planting.
It is always good to see the plants which we planted together are growing well. This semester, we worked on several plantings works from different plant species to different soil types. By working on the green roof this semester, I learned how green roof and living walls are installed and designed. What a great experience!
The first week, we did some clean works, like getting rid of weeds. Then we had planted a living wall on the right side of the roof. It is a great success. Plants are growing pretty good and flowers are blooming.
The first step to assemble the green wall was transplanting all of the plants into the green wall module systems. This took the most time for us to complete. To transplant we took put some soil in the module then we packed in the transplant plug and topped it off with more soil. Then at the top row of each module we added some fertilizer pellets. We only added them in the top row because the irrigation will run the fertilizer through the rest of the module.
After we finished transplanting all the modules we lined them up for assembly. The plan was to create “drifts” of different plants to make the finished wall a coherent design. After this we put the modules up, and finished the wall.
We started off taking all of the modules off of the existing wall and cleaning them out. There were lots of cockroaches and spiders in the existing wall. We found 10 cockroaches and more spiders than we could count.
After this we cleaned out all of the modules. We placed all of the soil and organic matter into bins to reuse on the next green wall. Then we washed out the modules and lined them up to be used in our transplants.
The first project we worked on was the Rooftop Garden. We planted several different common crops in the existing modular system on the roof and wanted to see how they would grow. This project was overseen by the undergraduate team for the planting phase.
We planted Swiss Chard, Lettuce, Parsley, Tomatoes, and several other plants.
Modular Green Roof
The second project our team worked on was creating a new set of Modular Green Roof sections that we would test. We had three systems set up, all the systems were set up in the same plastic modules with the same materials, but we changed the amount of soil and gravel in each set of modules. One set had one inch of gravel in the tray, followed by some filter fabric, and filled with soil. Another set had three quarters inch of gravel in a tray followed by the filter fabric and filled with soil. The final set had only a half inch of gravel, the filter fabric, and topped off with soil. We set up these systems, watered in the soil, then continued on to the major project for the semester.
Final: Over lay grass flats onto soil and gravel and allow then to take root.
Modular Green Wall
This was the largest project of the semester. We worked on two Green Walls. One we replaced a portion of the wall, the other we replaced the entire wall. We dissembled the existing Green Wall and emptied out all of the waste material for two weeks. Then we prepared all of the modules for transplants, and transplanted the selected plants the next two weeks. After this we organized and put up all of the transplanted modules the final week to create our roof top Green Wall.
The last project we wanted to complete was re planting one of our green walls. Over the course of this semester we have successfully unweeded already established beds, other sections of our green walls have already been replanted, while we also produced new sections of green roof bedding for further study. As we come to a close, we will discuss the stages we went through and what I personally took away from the over all experience.
This slide show runs a series of photos that were taken as the construction of the bed was created.
Stage 1: Take down panels from the green wall and empty the plantings from them while keeping the majority of soils in tacked. While we were sponsored more materials, we found it important to save whatever materials we already had, thus making them spread further in the long run.
Stage 2: Provided plants had to be transferred to planting panels. Due to having such a large multitude of plants, we had to make it a priority to get the more stressed plants established as soon as possible. To do this we formed an assembly line that cleaned panels, passed plants into panels with new soil and fertilizer.
Step 3: After two weeks of plantings, we completed the panels. The final step included placing the panels back on to the wall and allowing them to take further root.
In conclusion, there is still much work to be done. I have learned a lot about the proper processes to consider and what elements play a larger role in the success of green roofs. My initial interest in the subject took root about year ago. The idea to improve the heat index, water quality, and slow storm surge really appeals to me. To add to all of these effects there is also the aesthetic value, by learning more about them I might perhaps be able to apply this to my future work.
Lastly, we were given the task of uninstalling and reinstalling the existing green wall. First, we weeded the invasive grasses to disable the growth onto the new plantings. Second, we took down each module, emptied, and cleaned them out to ensure there would be no weeds for the new plants. Lastly, we installed each module with the new soil, various plant type, and fertilizer. Then, we arranged the wall according to texture, growing season, and aesthetic for an overall successful green wall.
There was evidence of pests within the wall from the over-wetness of the wood, which attracted roaches, spiders, and worms. These are all contributing factors to the positive and/or negative growth to the plants, which cannot be quantified throughout our research. So, we resealed the wall with protectants to prevent this.
In week two, we were given the task of creating a new module. First, we hauled a ton (literally felt like a ton) of 50 lbs. of soil bags onto the elevator from the ground floor. It was a long and arduous process and it took a while to figure out a way to methodically do so without over-weighing the elevator. We eventually figured it out.
Once all of the bags where on the roof, we laid out each empty module quartile and aligned them with the existing modules. Then, we filled them up accordingly. The base layer with the fabric followed by the soil and topped with the gravel. This process helps with the movement of water through each layer and the ability to retain at the base.
Photo: Soil and gravel installation to each module quartile.
Step 1: Laying out the panels in two different sections to allow later comparison between the two.
Step 2: Lay a higher amount of gravel in one section rather than the other. This resulted in there being more soil in one than the other.
The first class we got right to it. Dr. Jeremy Merrill had already bought an extensive amount of vegetables and herbs that he wanted to develop his research on. He was able to get an array of vegetables such as tomatoes, peppers, squash, pumpkin, etc. that also had a variety of growth patterns and conditions. In doing so, it allowed us to observe the which were inhabitable on the roof and what wasn’t. I’ve learned the proper way to install new plantings by loosening the roots to allow flexible growth and placing them into the pre-dug slots.
Photo: Me shearing and planting Thai Chili Peppers into random modules with different herbs and vegetables.