Steinhardt Conservatory

Brooklyn Botanic Garden's first glasshouses went up alongside its laboratory and administration building, designed by McKim, Mead & White in a Tuscan Revival style. The building and its Palm House opened in December 1913 with about 250 plants of 140 species, while the garden itself dates the dedication of the complex to 1917. Wooden greenhouses stood alongside the Palm House. In 1925 a gift of 32 bonsai from the local plantsman Ernest F. Coe founded the bonsai collection, which gained its first curator, Frank Okamura, in 1947.

By the mid-1980s the Palm House and the neighbouring wooden greenhouses had badly deteriorated. In 1984 the garden announced that it would build a new conservatory and restore the Palm House, and work began that May, the first major construction in the garden since the 1910s. The design went to Davis, Brody & Associates, a New York practice founded in 1952 that became Davis Brody Bond in 1996. The cost, around $25 million, was met in part by $3 million from Michael and Judith Steinhardt and $11.65 million from the city. The conservatory was named after the couple in March 1988 and opened on 19 May 1988.

The restored Palm House, outside the conservatory circuit, serves as an education centre and event venue and has housed a café since 2017. The C.V. Starr Bonsai Museum and the conservatory gallery were redesigned in 2007, and the bonsai collection marked its centenary in 2025.

The Steinhardt Conservatory occupies the eastern part of the garden, just south of the laboratory and administration building. It is made up of four structures: a 245-foot (75 m) main wing along Washington Avenue and three octagonal pavilions, each devoted to a different climate. They cover some 40,000 square feet (3,700 m²) and are linked by tunnels; the garden gives 65 feet (about 20 m) for the Tropical Pavilion. Their envelope uses roughly 60,000 square feet (5,600 m²) of glass in panes measuring 3 by 7 feet, and the metal framing is painted green to match the facade of the historic building.

The Tropical Pavilion, the largest at about 6,000 square feet (560 m²), is tall enough for trees and has waterfalls and streams modelled on a rainforest. The Desert Pavilion is designed as an arid landscape split into two geographical halves, while the Helen Mattin Warm Temperate Pavilion recreates the conditions of regions with cool, wet winters and hot, dry summers. The main wing holds the bonsai museum, the aquatic house and a trail devoted to plant evolution.

The Tropical Pavilion brings together food, medicinal, industrial and ornamental plants from the Amazon basin, the African rainforest and tropical eastern Asia: bananas from Southeast Asia, rubber trees from Central America, palms from Madagascar and crotons, above an understorey of familiar houseplants. The Desert Pavilion shows plants from the south-western United States, Mexico, Peru, Bolivia, Argentina and Chile on one side and from Africa, Madagascar, the Canary Islands and Australia on the other; Madagascan plants, living stones and desert ephemerals are its highlights. The Warm Temperate Pavilion gathers Mediterranean, South African, Australian, New Zealand, East Asian, Californian and west-coast South American plants adapted to drought and sometimes fire, with an extensive collection of South African bulbs.

The C.V. Starr Bonsai Museum holds more than 400 temperate and tropical bonsai, some well over a century old and many still in their original containers, trained in classic windswept, slanting-trunk, rock-clinging and forest styles; around thirty are on show at any time. It is the second oldest collection in the United States, after that of the Arnold Arboretum. The Robert W. Wilson Aquatic House contains tropical water plants, carnivorous plants and orchids, and the Trail of Evolution traces 3.5 billion years of plant history.

The conservatory lies on the eastern side of Brooklyn Botanic Garden, along Washington Avenue, next to the Palm House and its café. It combines naturally with the outdoor gardens, especially in spring when the cherry trees bloom. In winter the glasshouses take over from the outdoor gardens: February and March are the best months for the Warm Temperate Pavilion, when its South African bulbs are in full flower.

The bonsai on display change with the seasons, as trees move regularly between the back-of-house nurseries and the galleries; the collection's centenary in 2025 brought an expanded display, new interpretive signage and special tours.