The Final Plant

As the year wrapped up the green roof was extensively planted. There was a big end of year planting party where we wrapped up the planting for the semester. On the middle living wall many plants were literally wrapped up, in cloth, and placed on the new and improved wall. I hope that the plants survive on the wall, and I think that they have a better opportunity to do so than ever before. A few adjustments were made to the wall to improve it this year, and now more water and sunlight than ever is getting to the plants. This was largely accomplished by trimming a lot of the excess cloth off of the face of the wall. The cloth was absorbing a lot of the irrigation, and then dripping it down onto the ground. The extra cloth also shaded some of the plants, which is especially harmful for a living wall. Since the wall is vertical and opaque the plants only get about half as much sunlight as plants in the ground, and any additional shade only puts plants at a greater disadvantage. In an earlier post I wrote about the current irrigation system’s failure, but it turns out that I spoke too soon. After waiting about 5 minutes I was able to see that the water makes it most of the way down the wall, and every single pod looked to be getting some irrigation.

We also finished providing the roof garden with ground cover, and now it is thickly planted as pictured.

Post #2 Green Roof Remix

On the green roof there were two different sections, One section of pods had been planted as succulent garden and the other section was filled with small brush and grass had been let loose for over a year and formed a “roof prairie”. Just about every plant survived, and this semester every plant was growing. There were even one or two blooms each in the garden, but the succulent garden also had quite a few weeds coming up.  To try to get rid of the weeds permanently we mixed some of the roof prairie modules in with the succulent garden’s modules.IMG_1153 This way the smaller prairie plants would cover all the open ground that the weeds were growing in.

The modules on the roof were a lot heavier than I expected, which made me think about the overall effects of a green roof. These modules were not just heavy with dirt, but they had continued to get heavier because of the amount of water absorbed by each one. Each module’s plants and dirt absorb and retain a pretty significant amount of water. The plant, dirt, and other materials were all measurably heavier than when the modules were first planted and just about all this additional weight comes from water. I have always thought that South Texas could really benefit from more green roofs because of this quality. A single green roof can absorb a large amount of water that would otherwise become runoff, which can significantly decrease an areas risk of flooding. I think that flood prone areas like Houston could use green roof implementation to help lower floodwaters. Obviously that is a big statement to make, but spending time on a green roof and getting familiar with what it is made of has made me really believe in the stated benefits of these roofs. The first time I heard that a green roof can reduce a building’s electrical consumption by 50% I thought it seemed a bit exaggerated. Now I can see from taking apart and carrying these modules that the dirt and plant material is a really substantial barrier, that I am sure provides excellent insulation.IMG_1156

Just the growth of the plants alone is extremely substantial. It was amazing to see how strong and thick the roots of some of the prairie grass became. When we took apart a module we saw that the roots had wrapped so tightly around the bottom of the module that the letters of the manufacturer were imprinted into the roots. These roots also tore multiple holes through a cloth that I couldn’t even cut with scissors. I always thought that grass was kind of puny, but this grass was nothing to mess with. Even though this grass was tough it was definitely struggling to survive on the roof, the grass was more grey looking than green, and the roots wouldn’t have been so concentrated on the bottom if they hadn’t been looking for more water. It is defiantly difficult to find plants that can thrive long term on the roof. Even though the amount of soil in each module is far from insignificant, the roof provides a limit that the ground just doesn’t have.

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This is how we would empty out the modules

After all the experiences of merging the prairie and succulents together, the roof seems to be doing well, and it looks like for the first time that the weeds are outnumbered by the plants we planted.

Post #1 The Living Wall

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Coming back into the semester the first thing I worked on, other than weeding was on the living wall #2. living wall #2 is needed a new irrigation system, because the old system only distributed water to about 20% of the individual cloth pockets. Right before the end of last semester we installed a new irrigation system using soaker hoses to try to get water into every single pocket. Last semester we did not have enough time to put up the irrigation system well or get all the materials, so the irrigation was haphazardly thrown up.

This semester with more PVC pipe and glue for attaching the pipes to each other we could actually fully install the new irrigation system and make a few adjustments from the failures of the first attempt. We started by taking all the hoses off of the wall, then we built a pipe to bring the water up to the top of the wall. Last semester we connected the hose to the soaker hoses at the bottom of the wall, which required the water to snake up the wall through several hundred feet of hose. As you might expect this was not a good method, and the water was only able to get up about a third of the wall.

After we made the pipe to get the water to the top of the wall, we began to put the hose back on the wall. Last semester for speed we had one person zip tying the hose to the wall starting from the top coming down, and another person starting from the bottom, so we could connect up in the middle. As it turned out there was about 20 extra feet of hose left when the two sides got to the middle, and so we had to attach a second layer of hose onto the wall. This did turn out to make putting plants in that row just about impossible. This semester the we did not have to create punctures in the cloth of the wall, which made things easier, but we made sure to install the hoses from the top down so there would be no doubling back in the hose. We ended up using one less hose because the hose was tight tightly to the wall in the and never doubled back in the interest of space and water flow.

Finally, after building the pipe, and attaching the soaker hoses, we screwed on the attachment joints the to the top end of the soaker hose and hose coming from the irrigation system. Then we got to put in the final step by gluing the pipe to the attachments, linking the wall’s soaker hoses to the irrigation system. Now, we had made a system where the water would be carried up to the top in a pipe and snake downwards crisscrossing the wall with soaker hoses so that water was dropped directly into every pocket.

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The water does not quite make it to the bottom, but the lower pockets do get some water from  water dripping down from up above, which I tried to show in this picture.

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We planted onion seeds, peas, and baby radishes on the wall, but only the peas have grown beyond a sprout.

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The irrigation system probably needs to have multiple points where water comes off of the main pipe on the side. There are also large swaths of fabric that shade the plants from sun and absorbs much of the water, so unfortunately despite installing a better system it was not good enough to grow plants on this green wall.