Asia's largest rooftop farm towers over Bangkok

Posted on 15 October 2020.

Built on the Rangsit campus roof, an urban farm run by Thammasat University - one of Thailand's oldest and most prestigious universities – proves it's possible to combine urban development and high environmental quality.

Bangkok is among the world's most vulnerable cities in terms of the effects of climate change. Built on swampy land only 1.5 m above sea level, the Thai capital is sinking by between one and two centimeters every year. Frenetic urban development and concreting the numerous canals crossing this "Venice of the East" mean that during the monsoon season it can no longer absorb the rainwater.
Consequently Bangkok regularly experiences devastating floods, the intensity and frequency of which are likely to increase over the next few years. According to World Bank forecasts, close to 40% of the city could be under water by 2030. In the face of this threat, Thammasat University wanted to demonstrate that it is possible to combine urban development and high environmental quality as a means of increasing both cities’ climate resilience and food security. On its Rangsit campus in northern Bangkok, it has established a huge 22,000 m2 green roof that is also home to Asia's largest rooftop farm.

From roof to table

The farm covers an area of 7,000 m2, which is 32% of the green roof. Inspired by the agricultural practices of rice growers in the mountainous regions of Southeast Asia, it replicates the structure of traditional rice terraces. This terraced roof layout facilitates water management by helping to slow down rainwater runoff. The rainwater is absorbed, collected and stored in one of the many retention basins before being used for irrigation.

Herbs, vegetables and a naturally drought and flood resistant variety of rice are grown here. The entirely organically grown produce is served up in the campus canteen and distributed to the community. Thammasat University claims it produces 3,745 kg of food and provides 133,000 meals a year. All the food waste is composted and used as organic fertilizer to boost the next season’s harvest. The local supply chain drastically reduces food-related greenhouse gas emissions (processing, packaging, transportation) and waste, as well as encouraging a healthy, low-impact plant-based diet.

Taking advantage of Thailand's abundant sunshine, Thammasat University's green roof is also equipped with solar panels capable of producing up to 500,000 Wh. The renewable energy is used to pump water to irrigate the urban farm and provides electricity to cool the air inside and outside the building.

With its self-sufficient urban farm model in the heart of Bangkok, Thammasat University is demonstrating that there is an alternative to supplying food to cities via the industrial agricultural system, which has potentially negative social and environmental impacts. And what’s more, when it’s adapted to local specificities and based on proven techniques and practices, urban development helps to overcome environmental challenges.