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Roots Up greenhouse collects mountain dew to water crops in Ethiopian highlands

Roots Up greenhouse collects m...
Roots Up has designed a greenhouse for use in hot, dry climates that collects dew for irrigating the crops inside
Roots Up has designed a greenhouse for use in hot, dry climates that collects dew for irrigating the crops inside
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Roots Up has designed a greenhouse for use in hot, dry climates that collects dew for irrigating the crops inside
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Roots Up has designed a greenhouse for use in hot, dry climates that collects dew for irrigating the crops inside

In hot, dry areas of the world, collecting enough rainwater to grow crops can be difficult. Another potential source of water for collection, however, can be dew. Roots Up has designed a greenhouse to collect dew in Gondar, Ethiopia, as part of a scheme to help local farmers with low-tech solutions.

The water collected is, of course, meant for watering the crops contained within the greenhouse. It can, however, be used as drinking water if needed. Like the Warka Water bamboo tower, the Roots Up greenhouse uses basic materials and simple to build.

The greenhouse is set into a pit dug into the ground and is built using locally-sourced bamboo, a polycarbonate sheet, a bioplastic sheet, ropes and a cistern water tank. It can be constructed by unskilled people with just basic tools and takes around five days to complete.

The polycarbonate sheet forms the pyramidal walls of the greenhouse, like a tent, and can be opened at the top. The bioplastic sheet is set up as a funnel in the center of the greenhouse and directs water into a tank. Water from the tank is then used to irrigate the crops.

The greenhouse works by trapping hot, humid air during the day and ensuring that it circulates rather than being lost. When the outside temperature drops in the evening, the top section of the greenhouse is opened, allowing dew to form on the the bioplastic sheet and run down into the water tank. This setup also allows for the collection of any rainwater.

According to Roots Up, the amount of water that can be collected varies depending on the level of humidity in the atmosphere. It says that in the high region of Gondar the humidity is around 50 percent in the dry season and estimates that up to 200 l (44 gal) of water a day can be harvested.

Roots Up is raising funds for its low-tech project with a flexible funding campaign on Indiegogo. The organization is aiming for the first prototype of the greenhouse to be built in June, after which it intends to roll-out its low-tech solutions in Gondar. Training will be delivered from September with an aim of 10 further greenhouses to be built by November.

The video below provides an explanation about how the greenhouse works.

Sources: Roots Up, Indiegogo

5 comments
charizzardd
pretty clever, I really love passive systems like this, something that could actually be affordable and sustainable in small unconnected communities
Richard Guy
Is it necessary to the design to dig the pit? Doing so will damage the soil structure and removing that amount of soil (looks a swimming pool's worth) would be very labour and energy intensive. Otherwise: looks great!
Dan Smith
Another question of design... Could you just take the top cone and invert it at night so that it becomes the water collection cone? Or does that drastically reduce daytime collection, if there is much?
And in response to Richard, I don't know for sure how much the pit affects the collection, but I would imagine the increased difference in soil temperature and air temperature might boost water collection. If you put the top soil aside and put it back in after removing the subsoil, it would probably be okay. It will take some time to build up the soil structure again, but considering the environment, the gain in moisture would probably out-due the initial damage over time. But of course this is just conjecture on my part. Cool idea that I'm going to have to try here in Colorado.
Ramesh037
About 40 years ago, a friend of my father and also an MP had undertaken the task of greening Rajasthan. His great help were the nomads who wandered the desert with their goats. He asked these nomads to collect the droppings of the goats. These droppings were spread on a small area. In the center seedlings were placed. The droppings would collect the moisture at night and thereby the seedlings would get the water to grow. This project enabled the people to green their desert. Till 1911, this part of India was the corn chamber but due to greed most of the trees were chopped off and thereby became a desert. Gradually the salt sank and the desert started to bloom. I think the effort being undertaken in Gondar shall succeed. A certain amount of manure shall accelerate the process I think.
Nik
Given that you'd need about 1000 square meters to be self sufficient, [1/4 acre] a very large number of these 'tents' would be required, which questions their viability from a cost and availability of materials point of view.