Green Terrace – from Waste to Life

A social bridge between Switzerland and Colombia

Text: Pedro Pablo Mejía & Alex Henao
Photos: Angélica García


  • Every day, 7’000 tonnes of waste arrive at the landfill, of which about 4’000 tonnes is organic waste that can be treated and turned into compost.
  • For every 100 kilos of organic waste that is no longer landfilled, for example, up to 420 kilos of CO2 equivalents are no longer released into the atmosphere.
  • The terraces are sustainable places where each family converts organic waste into compost and then into food by separating waste in their household kitchen.
  • Terraza Verde creates a social fabric around agriculture and environmental protection and thus connections between the people involved.

Self-grown vertical vegetable garden in a squatted neighbourhood

Stroking a small plant, eight-year-old Sofía emotionally and tenderly remarks that her plant has offspring: «Here, it is already maturing, and I’m taking care of it little by little. I go out with my grandmother and when I come back, I see her with little children». She planted it because she learned from her grandmother that «plants help protect the environment and produce food such as parsley». Sofía belongs to one of the 100 families participating in the Terraza Verde project, which is being implemented by the Skat Foundation together with the parish of San Marcelino Champagnat, under the leadership of Alfonso Canedo, in 19 neighbourhoods in the locality of Usme, in Bogotá, Colombia. Project participants learn here to produce compost from the organic waste they recycle in their homes. According to data from the National Department of Statistics (DANE), cited in 2021 by the Social Integration Secretariat of the City Hall, Usme has a population of 432,724 inhabitants, of whom 125,922 live in poverty and 22,457 in extreme poverty. Historically, this sector of the city has also been a settlement for people displaced by violence.

For people living in this part of the city, where the unemployment rate is at 10.4 percent, according to data from the Districts Oversight Office, it is a great help to plant vegetables for their own consumption and at the same time to apply recycling and waste management techniques in their homes. «One of the project’s main objectives is that people become aware of the importance of separating organic waste and using it to produce compost and to prevent impacts such as greenhouse gases and leachates with polluting concentrations», explains engineer Sandra Méndez, who works with the Skat Foundation implementing the waste management programme in Latin America.

Vertical gardens and composting

Each of the participating families receives a two-metre-tall and one-metre-wide vertical garden made of tarpaulin including twelve bags. Additionally, they are given food seeds such as coriander, parsley, lettuce, chard, paprika, chilly, long onion, potato, tomato, cape gooseberry and aromatic herbs. They also get fertile soil and compost produced in four 1.20-cubic-metre compost bins made from recycled wood. Ana Bertilda assures that she has benefited from this project: «It has been a very good experience because we have learned a lot about plants, about how to produce organic material, and how to process it. For me, as I suffer from obesity, this project has given me more knowledge on how to eat better and has helped me intellectually, physically, and psychologically».

The project leader recalls that the Terraza Verde model was designed at the peak of the pandemic, and that the project began in 2021 with the support of the Skat Foundation and its donors, including the Swiss Agency for Development and Corporation (SDC), the Catholic Church of St. Gallen, the Municipality of Maur and the Canton of Schaffhausen.

Canedo shares that «the idea is to transform the terraces into sustainable spaces for each family, with waste separation at source, for example in the house kitchen, and to convert organic waste into compost and then into food, vegetables, herbs…». He adds, «it is an ecological and green project on the terraces of our houses. It is urban agriculture».

Terraza Verde has changed life and perception even among oldest inhabitants of the district, such as Blanca González, who has lived in the area for 35 years, and says, «before, we had our maticas (plants) as usual; but now we know how to do things much better. Because they explained to us how to prepare the water that is added to the onion or how to crush the eggshells to add them to the compost and have a fertiliser rich with calcium».


Ana Bertilde Gómez is one of the project participants who has started to earn money with the products she grows. She makes and sells salad dressings and marinades. The income is equivalent to about a quarter of the minimum wage in Colombia. With this, she can cover expenses for her family.

Almost everything can be recycled

Every Saturday, training sessions are held. «There are always practical and theoretical activities on ecology, waste management and urban agriculture», Canedo explains. At each meeting, about 25 kilos of organic compost is given to families, depending on their need.

Another resident of the sector, Carmen Rosa, highlights everything that she has learned about ecology. For her, the training with Sebastián Merchán, an ecologist from Javeriana University, has changed her mentality: «I have always been very close to the countryside. I know how to plant, but the garbage, which you can’t really call garbage, because almost everything can be recycled, struck me. We already know how to organise things, and what is useful and what is not. Only very little of what is left is waste».

For Merchán, one of Bogota’s problems is the 7,000 tonnes of waste disposed daily at the Doña Juana landfill, out of which about 4,000 tonnes are organic waste that could be treated and turned into compost. Currently, the compost bins have the capacity to collect an average of 100 kg of organic waste per week. Currently, as there is no space to receive more, the waste is collected from around 20 families. What is gathered represents between 50 percent and 60 percent of the waste generated in each household before the start of the project. «Many families who do not bring their waste to the Terraza Verde do their own home treatment, mainly with worms. Some even do their small composting on the terrace itself, reducing their waste by at least 20 to 30 percent», adds engineer Méndez.

Once filled, each of the compost bins takes about three months to generate between 50 and 60 kilo of compost. This is enough to fertilise the seedlings planted on the Terraza Verde, and to mix them with the soil in the vertical gardens that are delivered to the families. It is known that for every 100 kilo of organic waste that is no longer dumped in landfills, for example, up to 420 kilo of CO2 equivalent is no longer emitted into the atmosphere. «In this way, we are contributing to the reduction of greenhouse gas emissions», Méndez notes.

Motivation to study

Ángela Sofía, a young woman involved in Terraza Verde, gets excited when she talks about the project and the passion she has for the technology, which consists of producing humus as a fertiliser: «Earthworms produce it naturally by digesting organic waste. We feed the earthworms with the peels, mostly fruit peels, because they like sweet things. The waste is chopped up, and they digest it much faster. They release humus as a liquid which is mixed with water, and the compost is generated to fertilise the plants».

Thanks to the project, Ángela Sofía decided to take two courses at the National Training Service (SENA) to learn more about agriculture. She has also enrolled for a technical course in agricultural projects and now dreams of going to university to study biology or agricultural engineering. «I’m already in the process of making that dream come true», she says with a twinkle in her eye.


According to Canedo, each vertical garden has twelve bags that produce vegetables, which is not enough for each family to produce a surplus for sale. «But if I can increase the number of vertical gardens to five or ten, then that changes things, and we could sell or we could talk about trading different products». He adds that to be able to sell the products, an investment of at least 700,000 pesos (177 CHF) per family would have to be made. «It’s not a huge amount, but with more vertical gardens, it would be possible to produce a surplus. For now, with just one vertical garden per family, we are starting to motivate people to love this. People already know, for example, how to separate waste at source, and that is a huge gain».

However, active project participants like Ana Bertilda are already starting to sell salad dressings and marinades on a small scale. «At the moment I’m producing 244 100-gram glasses in four days», she says. Production is at a unit cost of 2,000 pesos (CHF 0.5). Her enterprise is still a pilot, whose current profitability (about a quarter of the minimum wage in Colombia) will improve with the support of professionals from Javeriana University through its social programme Prosofi and other institutions that offer training and seed capital for this type of initiative. «My husband and I are involved in the production», Ana Bertilda emphasises, demonstrating the potential not only for economic opportunities, but also for strengthening the family nucleus. So far, it is estimated that 10 percent of the families sell or exchange the food produced on the terraces.

Children’s participation

For Sandra Méndez, children play an important role in the process: «It is the children and young people who will ensure longstanding changes because they are the ones who educate at home». The ecologist conducts workshops every week with groups of 60 to 70 children and says that they «already know about issues such as deforestation or illegal animal trafficking». In total, about 380 children have participated in the workshops and have learned about composting, ecology, waste management and ecological issues in general.


Children and young people are also actively involved in the project. Kitchen waste is rich in nutrients and can therefore be used for compost as well as for worm cultures (and thus for humus production).


Children learn in practical courses how to raise herbs and how to cultivate the family garden.

Sowing is recovering

Because of the pandemic, social relations between neighbours and families suffered greater rupture than they had before. For Yeny Carolina, a social worker, this project offers a deeper vision: «The Terraza Verde project, from my point of view, creates a social fabric around ecology and agriculture, and generates links between people». For example, Odilia, a social leader of an informal settlement, has a community compost bin. Around 13 families collect organic waste in a small bucket. They also have a vegetable garden, where they grow mint, parsley, pennyroyal, rue and tomato seeds. «What they are growing is being consumed by the families themselves. The truth is that there is a lot of poverty here», Carolina remarks. She adds, «the people who are doing this are grandparents or mothers, who are heads of households and who grow their coriander and tomatoes for their own consumption. One of the advantages of being in this project is that at least we keep our minds on other things, we relate to each other, we are brought together and we are aware of each other’s needs». Meanwhile Blanca Díaz, who lives in another neighbourhood of Usme, explains that her life has changed with this project because they make better use of their time and have the opportunity to do things with other people. She adds, «Some of us from the parish visit the houses of community members, we help them to sow, and we take them the seeds. This is a project that is not personal, it is communal».

An alliance with a future

For Alfonso Canedo, the support of the Skat Foundation has made him feel encouraged. Now he has the backing and the resources to hire a technical expert, to buy seeds and to bring together 100 families. «Without this support, we would be working with a maximum of five families», Canedo says, suggesting that the project could be extended to the whole city through the Archdiocese, with the support of Javeriana University and other entities such as the Botanical Garden and schools. Furthermore, there is also the possibility to engage local city halls, the mayors and private sector actors such as supermarkets. «This laboratory allows us to demonstrate to other communities that it is possible to make this project a reality. With more time and resources, it could be replicated in other places», Canedo maintains. Sandra Méndez explains that this is the first phase of the project. «We are documenting it to facilitate its multiplication. It has been a very enriching process because we started with just a few families, and we have seen how the interest of other communities has grown during the course of the year», she says.

When talking about the future of the project, Canedo explains that it would be ideal to first rent a farm, because the parish borders with the rural area, and then start a community process. The urban area requires a lot of mosquito and pest control. However, in a more rural area, the management of the compost bins would be enhanced. «We have made projections, and in three years, with an investment of about 300 million pesos (75,800 CHF), this project would already be profitable, because people are liking this green wave, this organic food», he says.

The current phase runs until February 2023, and it is planned to continue with training and education workshops for families to keep implementing their Terrazas Verdes, and for those who are motivated to start their own business. The results of the experience will be disseminated so that it can be replicated in other places.