In some of the most poverty-stricken areas of Sub-Saharan Africa, 25mm of rain can fall in a single day. The next day, almost all of it will be gone. People in arid and semi arid areas need to make the most out of the little water they have. As part of out IB Group 4 Project, we intend to make a device that can easily collect water from gutter systems on homes, and then use this water usefully. In this case, we want the water to be used to sustain a small garden. We hope to make this a cost effective model and use only recycled materials.

Currently, our idea will be to construct a self-watering hanging garden using recycled materials or materials sourced from reverse garbage. Our hanging garden will be designed in such a way that it allows rainwater to enter the system, move into the pod-like mini garden beds and eventually leave if there is an overflow of water in the system. Due to the small size of the pods, and their small opening at the top, these gardens would be designed for herbs, smaller salad leaves or small vegetables. We imagine that this system would be useful in arid environments as the water is collected and would slowly seep into each of the pod gardens over a period of time.

So far we have communicated our idea to one another and have sourced our materials. We have focused highly on gathering recyclable materials to fit the characteristic as being eco friendly and efficient. Our immediate plan was to visit “Reverse garbage” to seek some recyclable materials that fit our particular idea. PVC pipes are a solid material for our plan and we were fortunate enough to find one that perfectly suited our plan. From Reverse Garbage we purchased the PVC pipe, 3 screws, a small hook and a wall mount all for $2.00. The small 300ml coke bottles costed 5 cents each. So all for $2.20, a simple but effective garden idea that can be easily used by anyone no matter where they are.

10:30 am Entry: As of right now we have completed trials of our designed self-watering hanging garden, in regards to finding the appropriate drill and hole size to fit the nozzles of the small bottles. Additionally, in order to allow us to fit the bottle nozzles into the holes in the PVC pipe. Finally, we have also decided the positions in which the holes for the bottles will be drilled.

1:00 pm: With all of our testing complete and our trial and error method of experimentation we are now satisfied with our first prototype, the water that was poured into the top of the pipe was almost evenly distributed amongst all four bottles, the issue of the pipe building up water was solved by drilling holes in the end piece near the top, in order for the water to exit if the water level gets too high. We did notice that water was moving soil in the pipe, as well as causing the water to shift as it moved into the bottle since it was moving reasonably quickly. We are hoping to resolve this issue tomorrow. 

9:30 am: After some careful consideration, we decided to add some muslin cloth between the pvc pipe and the bottles. The purpose of this is twofold, it firstly stops faster moving water carrying off soil, and also controls the rate at which water is absorbed into the bottles. Furthermore, the muslin cloth can extend into the pipe, which means that there isn't any water at the bottom because the water level is too small to fall into the bottle. We felt that this has fixed many of our issues, and are more happy with this version of our self-watering hanging garden. Finally, although we used muslin cloth, we hypothesised that any semi-porous material (such as cotton) could be used instead.

12:50pm: The project has now been concluded, after some more research, we felt that future models could use different materials and modifications in order to improve on what we had already done. Firstly, the production of PVC (polyvinyl chloride) projects large amounts of chlorine into the environment, which is extremely harmful. Although the PVC we used was recycled, we shouldn't encourage it's production at all. Instead, we believe that a metallic, such as copper, pipe would be a good substitute. Despite being expensive, copper piping is light and rust resistant. Another issue we could resolve is the build-up of any water in a bottle, which could be solved by adding small holes in the bottom of the bottles. The soil would still absorb the water it needed, but any excess water would be ejected. Finally, we would like to suggest that this device is just a model, we calculated that it can take up to 150ml of water at a time, and can slowly take more water over time. We believe that a larger model would greatly increase the amount of water the device can take at a given time.

Conclusion: Overall, we all found this to be an extremely interesting and intruiging experience. It was truley refreshing to work with and experience different viewpoints of people from other scientific disciplines. We all learned something new from one another, and all had something to contribute in order to produce the final product.


Initial sketch


All the team members working on the device