Anantara Riverside Bangkok Resort’s ambitious green roof serves the environment while providing tasty produce
Modern city hotel roofs are generally flat slabs that no one sees unless they live in a neighbouring building. But if that neighbour happens to be an affiliated hotel, then the expanse of exposed concrete becomes a design issue. This was the case when the management of the Avani Riverside Bangkok looked down from the relatively new hotel’s 17th floor onto the bare third-story roof of their sister property, the Anantara Riverside Bangkok.
Deciding the roof needed refurbishment or at least some sort of masking, the owners considered different approaches.
“Several ideas, from a Japanese garden to an adventure mini-golf course, came to mind,” says Anantara general manager Nicolaus Priesnitz. “But the idea of an urban rooftop garden made a lot of sense.”
Once Anantara was committed to a roof project that would not only offer a more aesthetically pleasing landscape, but also provide fresh local ingredients for dining outlets at the two hotels, the hotel sought technological consultants.
The resort found the perfect partner in Chanuphan ‘Tong’ Horsuwan, a farm manager and international consultant at the Bangsai Agricultural Centre, located northeast of the capital.
Tong trained in urban farming under his father, Makavan Horsuwan, a well-known innovator in the development of hydroponic growth tables and trays, a technology which allows for simple modular expansion per space available.
“After university, I joined him on the farm and was amazed at how he could grow vegetables and crops anywhere—even in urban locations or on a roof,” explains Tong. “As populations grow in cities like Bangkok, there is increasingly less space to farm. Hydroponic city farming is an effective way of addressing this issue sustainably.”
Reliable, predictable and repeatable, hydroponic farming grows plants without soil, using nutrients and water only. At the Anantara Riverside Bangkok, these are delivered directly to the plants’ root systems inside three climate-controlled greenhouses, 29 plant beds, and a green canopy tunnel atop a 3,000 sq.m rooftop overlooking the Chao Phraya River.
Specific technologies employed by Tong and his team include a dynamic root floating system in which a nutrient solution is pumped into growth trays containing the plants, fully submerging the roots. For smaller, faster-growing plants, a thin film of nutrient solution is consistently applied to the roots without full submersion.
A sophisticated drip irrigation system recycles water used in the garden and assures a regulated flow of just the right amount of water necessary for the growth of each plant, thereby maximizing harvest and eliminating water wastage. No pesticides are employed. Meanwhile, a fogging system sprays water over the greenhouses, sprout rooms, and green tunnel to minimize potential damage by Thailand’s strong sun and extreme temperatures.
The elaborate system allows Tong and his team of young farmers at Anantara to grow organically certified melons, tomatoes, chilies, zucchini, cucumbers, mixed greens, and micro greens at an incredible harvest rate of up to 50 kilos per day. The produce goes a long way in Anantara’s kitchens, and enables the chefs to work with the freshest and highest-quality local ingredients possible.
Compared to a more traditional dirt-based farm, the roof garden’s hydroponic system uses 90 percent less water, 70 percent less land, and 50 percent less fertilizer. Environmental benefits of the massive roof farm include lowering urban air temperatures by mitigating the ‘heat island effect’ typical of highly urban Bangkok.
I’ve no doubt that the interior spaces below the green roof now require much less air-conditioning than before the farm was established, and I’m willing to bet that it also helps insulate the building for sound.
The highly successful roof garden bolsters Anantara’s green rep after having earned the Asean Green Hotel Award in 2015 as well as recent gold status from Green Growth 2050, the global sustainability certification standard for travel and tourism.
“Looking to the future, I want to take this initiative even further by designing and growing more hotel farms,” says Tong. “The project also teaches owners and guests about the long-term value of urban hydroponic farming. I hope to discover more ways to combine engineering and agriculture and to develop growth systems that are even more efficient and technologically advanced.”
Anantara’s rooftop farm serves as an impressive example of how unused urban concrete spaces can be transformed into something of sustainable benefit to any neighbourhood in the city. One only has to look to the sky.