Roster Tepidarium, Giardino dell'Orticoltura

The Tuscan Horticultural Society was founded in 1854 by the Accademia dei Georgofili. In 1859 it received on a perpetual lease, from Marquis Ludovico Ginori Lisci and Marchioness Marianna Venturi, the land outside the Porta San Gallo on the via Bolognese where the Giardino dell'Orticoltura now lies. In 1880 the Italian Horticultural Federation held its first national exhibition in Florence, and the Society decided to complete its garden with a large tepidarium.

The commission went to the architect-engineer Giacomo Roster, who drew, according to the press, on Joseph Paxton's Crystal Palace (1851) and the Royal Horticultural Society's winter garden in London (1860). Works are said to have begun in 1878. The inauguration took place in May 1880 (on the 19th according to most sources), and a chronicler of La Nazione spoke of a 'crystal palace'. The glasshouse hosted concerts, exhibitions and events.

The City of Florence acquired it from the Society in 1930. In poor condition, it received restoration funds between 1933 and 1936 and was damaged again in the Second World War. One restoration is dated 2000; by the late 1990s parts had collapsed and glazing was missing. A new 750,000-euro project was approved in 2011, and the press reported the works as completed in April 2013.

The Tepidarium stands on a rectangular plan of 38.50 by 17 metres, with about 650 square metres under cover, and reaches 14 metres in height in the central nave. According to the City of Florence, twenty-four cast-iron columns, cast in Pistoia by the Lorenzetti foundry, carry the structure; they are designed to drain rainwater, and the glazed roof was devised to prevent leaks. The metal frame is the work of the Officine Michelucci, also of Pistoia, and the whole was assembled from about 9,700 pieces, including eight tonnes of iron.

Inside, a raised walkway about 6 metres above the floor of the nave lets visitors look down on the plants. Two basins with niches, decorated with sponge-like rockwork, are by the Florentine carver Francesco Marini, in homage to Mannerist architecture; they recall the grottoes of Boboli. The glasshouse was heated by stoves; the 2011 project provided for heating and cooling by heat pump and radiant floor panels.

The Tepidarium was designed to receive exotic plants, which had to be protected from the Florentine cold by stove heating. The sources consulted do not describe a permanent collection today: the glasshouse works mainly as a large exhibition volume within the garden, which belongs to the Tuscan Horticultural Society, and it hosts exhibitions and events, including botanical art shows, talks and workshops during the plant fair.

That fair, organised by the Society in late April or early May, brings together more than seventy exhibitors from across Italy: flower growers, nurserymen and specialists in succulents, orchids, citrus, bulbs and herbs. The Tepidarium also hosts quieter gatherings, such as 'Un tè con le farfalle' (a tea with butterflies).

The Tepidarium stands in the Giardino dell'Orticoltura, north of Florence's historic centre. It opens for exhibitions and events, so it is wise to check the garden's calendar before going. The best occasion is the plant and flower fair of late April and early May, when the glasshouse is also a venue for talks and exhibitions.

The Giardino dei Semplici, already in the atlas, lies about a kilometre away as the crow flies, making it possible to pair two very different Florentine glasshouses in the same half day.