Transform Your Backyard: Simple Greywater Food Circles.
Table of Contents
In Windhoek, Namibia, food circles have emerged as a transformative approach to urban agriculture, particularly within informal settlements. Food circles are the signature project of the Kambashu Institute, a permaculture learning centre in Windhoek’s informal settlement.
Concept of Food Circles
A food circle is a permaculture-based gardening system designed to maximize resource efficiency and yield in limited spaces. Central to this design is a pit filled with greywater and organic biomass. Surrounding this pit, a berm is constructed where a diverse range of vegetables and fruit trees are planted. This arrangement allows the plants to access moisture and nutrients from the pit, promoting healthy growth even in arid conditions. Over time, the organic matter undergoes a cold composting process, enriching the soil and enhancing fertility. This method not only facilitates food production but also generates organic fertilizer, creating a self-sustaining ecosystem.
Implementation in Windhoek
The Kambashu Institute, established in 2021 by Ina Wilkie, serves as a permaculture learning center tailored for residents of Windhoek’s informal settlements. Recognizing the challenges posed by limited access to resources, the institute focuses on practical solutions such as food circles. Participants engage in hands-on training, learning to cultivate crops like cabbage, spinach, and carrots using minimal water and local materials. This approach not only addresses immediate nutritional needs but also fosters community resilience and self-reliance.
Impact and Community Engagement of Food Circles
The introduction of food circles has led to significant positive outcomes in Windhoek’s communities:
• Enhanced Food Security: Residents can grow their own nutritious food, reducing dependence on external sources.
• Economic Empowerment: Surplus produce can be sold, providing an additional income stream for families.
• Environmental Sustainability: Utilizing greywater and organic waste reduces environmental impact and promotes sustainable resource use.
• Community Cohesion: Collaborative gardening projects strengthen social ties and foster a sense of collective responsibility.
Through the efforts of the Kambashu Institute and the dedication of local residents, food circles have become a cornerstone of sustainable urban agriculture in Windhoek, exemplifying how innovative, community-driven solutions can effectively address food insecurity challenges.
In practice, the food circle developed by the Kambashu Institute operates as a simple yet highly effective system for growing food in challenging urban environments like Windhoek’s informal settlements.
Here’s how it works:
Food Circle Design and Structure
• Central Pit: At the heart of the food circle is a circular pit, typically around 30 cm in diameter and 50-60 cm deep. This pit acts as a composting and moisture-retention hub, filled with greywater (wastewater from household use, such as dishwashing or bathing) and organic biomass like food scraps, leaves, and paper.
• Surrounding Berm: Around the pit, a raised berm is formed using soil mixed with compost. This berm is where the plants grow. Its shape ensures water and nutrients from the central pit seep outwards, reaching the plant roots.
Food Circle Operation and Maintenance
1. Watering with Greywater: Instead of using fresh water, residents pour greywater directly into the pit. This water, filtered naturally by the composting material, hydrates the soil and plants while conserving scarce water resources.
2. Composting Process: The organic materials in the pit break down over time through a cold composting process, meaning no high temperatures are required. This process gradually enriches the surrounding soil with nutrients, promoting healthy plant growth.
3. Planting and Crop Rotation: A diverse mix of vegetables—such as cabbage, spinach, tomatoes, and carrots—are planted on the berm. Companion planting techniques are often used, where different crops support each other’s growth. Fruit trees like mulberry, lemon and guava can also be planted at the edges for shade and additional produce.
4. Maintenance Needs: While the food circle is a low tech solution, the Kambashu Institute actually encourages a lot of maintenance, based on the first permaculture principle: observe and interact. The objective of the Kambashu Institute is to spark design thinking, so regular, daily observing and interacting is key. One the grower has settled in a routine of feeding the pit with kitchen waste and greywater, the plants naturally receive water and nutrients, reducing the need for frequent watering or fertilisation.
The Institute puts it like this: “People can grow trees and vegetables using their grey water. With the water you have used to wash your vegetables, you can water your vegetables. With the water from the bucket shower, you can water your trees. The soapy water from washing dishes or clothes can go into the pit. Here you produce compost to improve your soil so that it can handle soap better.“
5. Organic Fertiliser Production: As the composting process continues, the pit produces rich, organic fertiliser that can be harvested and used in other parts of the garden or to start new food circles.
Benefits of food circles in Practice
• Water Efficiency: By recycling greywater and retaining moisture, the food circle uses up to 70% less water than traditional gardens.
• Nutrient-Rich Soil: Continuous composting enhances soil fertility, leading to higher crop yields with minimal external inputs.
• Adaptability: The design can be adapted based on available space and resources, making it ideal for small urban plots.
• Community Involvement: Families often manage food circles together, fostering community spirit and shared responsibility.
Through these practical methods, the food circles offer a sustainable, low-cost solution for growing food in arid urban settings, empowering communities to combat food insecurity while conserving precious resources.
To visualize the concept of food circles as implemented by the Kambashu Institute in Windhoek, Namibia, you can refer to the following resources:
• Kambashu Institute’s Official Website: This site provides detailed information and images of their permaculture projects, including food circles.
• Global Earth Repair Foundation: Features an article on the Kambashu Institute, showcasing images of their initiatives.
• Growing Food in Windhoek Facebook Page: Regularly shares updates and photographs of food circle projects and training sessions conducted by the Kambashu Institute.
• The African Journal of Landscape Architecture: Features an in depth article on the Kambashu Institute and their work with the Food Circles.
• World Future Council Award: With their food circles the Kambashu Institute won a World Future Council Award. Testament to the great work they are doing!
These resources offer visual insights into the structure and impact of food circles in promoting sustainable urban agriculture within Windhoek’s informal settlements.
Worthwhile books:
There are very few books that focus only on greywater pits or greywater-fed food circles, especially in the African or arid urban context like Windhoek. However, here’s a list of the most specific and practical books that directly address the greywater pit systems used in food circles — including banana pits, mulch basins, and greywater-fed basins.
1. Create an Oasis with Greywater – by Art Ludwig (Most relevant and specific)
• This is still the most practical book globally on greywater reuse.
• It includes:
• Mulch basins (exactly what Windhoek food circles use),
• Branched drain systems,
• Greywater-fed plant basins and pit designs.
• Diagrams, flow calculations, do’s and don’ts.
• Most systems in the Windhoek article could be built using this book alone.
• Covers simple greywater pit systems, laundry-to-landscape systems, and low-tech designs for drylands.
• More modern and user-friendly than older manuals, with African-style examples popping up in similar environments.
• Clear how-to guidance for urban households and community projects.
• More technical, but includes case studies and principles for water reuse in cities like Windhoek.
• Covers household and community-scale greywater reuse for urban agriculture.
• Best if you want to integrate food circles into urban planning or policy discussions.
Bonus Practical Resource (not a book but excellent):
• Greywater Action (www.greywateraction.org) – Online PDFs, design manuals, and case studies.
• Especially their “Banana Circle How-To” and “Mulch Basin Guidelines” are exactly what your Windhoek food circles follow.
Why This Approach Is Key to Ending Poverty and Hunger in Namibia
Namibia is facing a critical turning point. With one of the fastest-growing urban populations in Southern Africa, cities like Windhoek are expanding rapidly—yet this growth is not matched by adequate infrastructure, employment, or food security. The majority of new urban dwellers are settling in informal areas where access to land, clean water, and nutritious food is extremely limited. Rising food prices and climate change are compounding the crisis. Many households depend on processed, imported food, while nutrient-rich vegetables are either unavailable or unaffordable.
This is where small, regenerative growing systems become a game-changer. By turning everyday waste—like household greywater and kitchen scraps—into nourishment for plants, families can begin to grow real food right outside their homes. These systems don’t require large plots of land or expensive inputs. They use what is already present: dishwater, old basins or tyres, organic matter, and a bit of know-how. Once the basic setup is in place, they provide a continuous supply of herbs, greens, and even root vegetables, right where people live.
But the impact goes much further than what’s on the plate. These micro-systems reduce household expenses, especially for women who often bear the responsibility of feeding the family. They give children access to better nutrition, which improves their ability to learn and thrive. They reduce pressure on municipal services and build a culture of reuse, resilience, and self-reliance.
Perhaps most importantly, this model is not just for urban settlements—it can travel. Many city residents are originally from rural areas. When they visit their home villages, they bring with them stories and practices. This is how real knowledge transfer happens—organically, community to community. With proper support and a little facilitation, these practices can be adapted to suit rural conditions, where water may be even scarcer but space is often more available.
What we are seeing is the emergence of a grassroots food revolution, one that starts with dignity and practicality. It is not reliant on external aid or large-scale agriculture. Instead, it builds on what people already have and know, enriching it with simple design and ecological thinking. When done at scale, this approach has the potential to dramatically reduce hunger, lower food imports, create small incomes through surplus produce, and even begin healing degraded soils.
Ending poverty and hunger in Namibia will not come from top-down programmes alone. It will come from empowering communities with the tools and inspiration to take back control of their food systems. Regenerative home growing, rooted in practical solutions and cultural adaptation, may well be one of the most strategic investments our nation can make—for our cities, our rural areas, and future generations.
