Feeding the city, cooling the city

Ibu Ratna moved to Depok 37 years ago from her hometown in Banten, Indonesia. Over the years, she has watched the place grow into an increasingly busy and crowded satellite city of Jakarta, the nation's capital. The land around her home, once filled with fruit trees and food crops, has since been taken by buildings. Green and open spaces have steadily shrunk as the city's population grew.

What Ibu Ratna feels is not just her imagination. Depok is one of Indonesia's most densely populated cities, home to 2.1 million people within an area of just 199 square kilometres. Over the past decade, green spaces have steadily given way to buildings and asphalt.

Depok is facing the challenges of rapid urban growth. As vegetative ground cover is replaced by heat-absorbing concrete and asphalt, city temperatures rise - a phenomenon known as the Urban Heat Island (UHI) effect. Satellite data shows that Depok's UHI footprint has expanded significantly over the past decade, and field measurements confirm that air temperatures across the city now consistently exceed normal ranges. Low humidity and weak air circulation make things worse, causing the city to heat up faster.

Beyond the heat, Depok also faces its own food supply challenges. According to Widyati Riyandani, Head of Depok City's Food, Agriculture and Fisheries Agency (DKP3), most of the city's food comes from outside the region.¹ This leaves residents vulnerable to price spikes and supply disruptions. At the same time, there is no integrated data or information centre that stakeholders can draw on to address these challenges.

Seeds of a solution

Since 2023, Rikolto, together with Bogor Agricultural Institute (IPB) and the NGO Perkumpulan Indonesia Berseru (PIB), has been working on a solution to the challenges facing Depok. Supported by the Government of Flanders through the Flanders International Climate Action Programme (VIKAP), the project Lowering the Heat, Feeding Citizens: Scaling Up a Circular Model for Urban Agriculture in Depok City set out to test whether urban farming, practised ecologically, could tackle both challenges at once: cooling the city and strengthening residents' access to healthy, affordable food.

The project worked with six urban farming groups across Depok, engaging 166 farmers across 18,040 square metres of urban land. Most participants were not professional farmers - they were homemakers, community organisers, and workers who took up gardening out of personal interest or a desire to grow their own food.

Ibu Ratna is one of the women who actively joined the project. It started with her leading gardening activities as part of early childhood education at the local nursery school (PAUD). A local community officer then invited her to form a women's farming group (KWT) to cultivate and make use of idle land in her neighbourhood. Together with 14 other women, Ibu Ratna founded KWT Sejahtera in 2023.

KWT Sejahtera's 700 m2 plot is tucked away at the end of a narrow alley in a dense residential neighbourhood. Behind rows of houses, concrete walls and parked vehicles lies a well-tended garden: neat rows of chillies, cucumbers, aubergines, and leafy greens, with a maggot cultivation unit at one end. It is all managed by women who, not long ago, had never imagined themselves as farmers.

Through structured training and consistent on-site mentoring by IPB University, KWT Sejahtera and five other participating urban farming groups built real farming skills - from ecological soil preparation (working with the soil's natural biology rather than synthetic inputs) and compost-making from organic household waste to biological pest control and precision fertilisation. Most importantly, the entire approach is pesticide-free, producing food that is not only locally grown but genuinely safer to eat.

To measure the effect of ecological urban farming on local climate variability, Automatic Weather Stations (AWS) were installed in each farming plot. The stations record meteorological data in real time -temperature, humidity, wind speed and direction, air pressure, and rainfall - helping farmers to determine planting schedules, manage fertilisation and pest control, and receive early warnings of plant disease and pest threats.