Flower Dome & Cloud Forest

The two cooled conservatories at Gardens by the Bay grew out of an international competition that Singapore launched in 2006 to landscape reclaimed land around Marina Bay. More than 70 entries came in from 170 firms in 24 countries. The British landscape practice Grant Associates won Bay South, the largest of the three gardens, while Gustafson Porter secured Bay East.

For the glasshouses, Grant Associates assembled a team of architects WilkinsonEyre, structural engineers Atelier One and environmental engineers Atelier Ten, working with Singaporean firms. Bay South, home to the Flower Dome and the Cloud Forest, opened to the public on 29 June 2012.

Recognition followed quickly: World Building of the Year at the 2012 World Architecture Festival, the RIBA Lubetkin Prize in 2013 and two MIPIM Awards in 2014, including Best Innovative Green Building. Singapore's Building and Construction Authority gave the conservatories a Platinum rating under its Green Mark scheme. The 2015 edition of Guinness World Records listed the Flower Dome as the largest glass greenhouse in the world, and it is widely described as the largest glasshouse without internal columns. Since opening, the Cloud Forest has also hosted temporary exhibitions that periodically reshape its displays.

Set along the edge of Marina Reservoir, the two conservatories together cover more than 20,000 m². Their structure is a composite: a glazed gridshell is braced by an external superstructure of radially arranged, arched steel ribs that carry the lateral loads and remove the need for any internal columns. The Flower Dome spans 1.2 hectares beneath 3,332 glass panels, enclosing a volume the gardens compare to 75 Olympic swimming pools. The smaller Cloud Forest, at 0.8 hectares, is filled by a 42-metre 'Cloud Mountain' with a 35-metre indoor waterfall.

Keeping a cool climate at the equator called for an unusual energy strategy, developed by Atelier Ten. Waste from Singapore's national parks, diverted from landfill, is used as biomass to generate energy for the site. The biomes are cooled by displacement and dehumidified with liquid desiccant systems; warm air drawn from the top of the Flower Dome travels through an underground tunnel to a nearby cluster of Supertrees, where it feeds the desiccant regeneration plant. The Supertrees also serve as air intakes and exhausts, and harvested rainwater circulates through the cooling system. According to Atelier Ten, in their first three months the conservatories used no external energy for climate control.

The Flower Dome recreates a cool, dry Mediterranean climate, held by the gardens at 23 to 25°C. It contains eight gardens devoted to Mediterranean and semi-arid regions on five continents: baobabs and bottle trees; a succulent garden of cacti, aloes and crassulas; flora of western and southern Australia; South African fynbos; a South American garden with monkey puzzle trees and Chilean wine palms; Californian chaparral; a Mediterranean garden of olives, figs, grapes and Italian cypresses; and an olive grove centred on a tree said to be a thousand years old. An African baobab here is the largest tree in the whole of Gardens by the Bay. At the centre, the Flower Field is replanted for a sequence of seasonal floral themes.

The Cloud Forest evokes tropical mountain forests between 1,000 and 3,000 metres above sea level, with humidity of 80 to 90 per cent. Ferns, mosses, epiphytes, bromeliads and tiny orchids grow alongside carnivorous pitcher plants and Venus flytraps. The Secret Garden alone holds some 7,000 plants of more than 135 species and hybrids.

Both conservatories stand in the Bay South garden by the waterfront, a short walk from the Supertree Grove. The gardens suggest allowing about an hour for the Cloud Forest, and a similar amount of time for the Flower Dome if each of its eight gardens is explored. In the Cloud Forest, a series of walkways, including the Cloud Walk and the Treetop Walk, wrap around the mountain and lead to the Lost World, the Cavern and the Secret Garden; several times a day the mountain is shrouded in artificial mist. The Flower Field in the Flower Dome changes theme several times a year, which rewards repeat visits. A walk among the Supertrees and through the outdoor gardens of Bay South makes a natural continuation.