Greenhouse of Nantong Botanical Garden (南通植物园温室)

Nantong Botanical Garden, completed in 2018 on 125 hectares and attached to Langshan National Forest Park, makes its greenhouse its showpiece: it is the building visitors see on entering. The architects, GEN Architects, say they worked on the project from June 2017 to June 2018 for the Nantong Urban Construction Group; the landscape design was entrusted to the Changzhou Landscape Design Institute and the glass facade to a Shanghai engineering firm.

The greenhouse opened to the public on 1 October 2019, during the National Day holiday. Local media described it as the largest glass greenhouse in Nantong and noted free admission, with free guided tours during the trial period.

The architects based the design on the image of a "light boat", echoing the site's position beside the Yangtze. In their presentation, the monk Jianzhen sheltered from the wind at Langshan on his third attempt to reach Japan. The building's skin, compared to a fishing net, refers to Nantong's fishing culture. The project was presented in the Chinese architecture press in August 2022.

The building has about 3,700 m² of built area, of which 3,200 m² is column-free. Its frame is a series of seventeen steel portal frames, spaced 6 m apart and spanning 30 m north to south, progressively rotated to give the roof a twisted surface. The saddle roof drops to 3 m at its lowest, reaches 16 m along the central ridge and 20 m at its highest point. This profile separates the climates: the rainforest and the desert plants occupy the two raised ends, the seasonal flowers the lower middle part, which limits exchanges between air masses of different humidity.

The glazing pairs two extra-clear laminated sheets, cut into flat triangular panes that approximate the warped surface; most measure under 2.5 m². At the foot of the facade, parallelogram-shaped vents admit air; on the gables, double rows of windows, and on the roof triangles that open like scales, release heat. In winter a boiler in the service building feeds radiators hidden in trenches behind the facade; in summer air is blown up from the floor and electric blinds shade the plants. A single fire compartment, without sprinklers, relies on hydrants and smoke vents.

At the opening in 2019, the press described three zones. The rainforest gathers several dozen species rare in the region, with paths, a small bridge and rockwork. The desert zone holds cacti, ball cacti and other large succulents. A flower zone blends into the other two, and miniature displays of Chinese and exotic orchids complete the circuit, along with a creative corner where visitors choose potted plants.

The architects describe an artificial landscape, a waterfall at the entrance, an aerial path, a suspension bridge and two levels of circulation. A project sheet from a Chinese design award (CREDAward) lists five zones: rainforest, palms, four-season garden, tropical fruit trees and specialist plants.

According to the 2019 articles and the architects, the greenhouse stands at the north-east corner of the garden, facing an artificial lake and a waterside arrival plaza; the main entrance is at the south-west, on the park side. To the south, the expanse of water faces, at a distance, the "Five Hills" (Wushan) tourist area.

The garden has eighteen themed gardens, among them aquatic gardens, a rose garden, colour gardens and a bonsai garden in the local style known as "two and a half bends"; its main path is 4.4 km long and the signs are written in Chinese, English, Japanese and Korean. The site is part of Langshan National Forest Park, which makes it easy to combine the visit with the nearby mountain on the Yangtze.