Behind the scenes: The service greenhouses
The plants displayed in the exhibition greenhouses represent only part of the Garden’s collections. In fact, they are only the tip of the iceberg. Teams of specialized horticulturists and gardeners maintain a large part of the collections for research and conservation purposes in the service greenhouses. This is also where plants are produced for our seasonal events. These greenhouses are grouped together in three complexes. In addition, there are the Louis Dupire greenhouses, where annuals and vegetable plants are grown.
- The service greenhouses cover 3.5 times as much space as the exhibition greenhouses – 14,000 m2 versus 4,000 m2.
- An 11-km long piping system carries water to the greenhouses for heating, irrigation and misting.
- Every year, 70,000 annuals and over 17,000 vegetable plants are grown in the Louis Dupire greenhouses by the Garden team.
- The propagation team, for its part, produces 18,000 plants (tropical plants, perennials, trees, shrubs and conifers) every year from seedlings or cuttings.
The very first greenhouses
The first facilities erected at the Garden in 1932 were an administration building, a boiler house and a greenhouse – the bare essentials! Production and exhibition greenhouses came later, and were officially opened in 1956 to mark the Jardin botanique's 25th birthday. In those days, a paved road separated the main building and the greenhouses.
It wasn't until the whole building was renovated in 1994 that the reception greenhouse was built, linking the building with the ten exhibition greenhouses.
The five greenhouses in complex A, opened in 1984, are dedicated to flower production and plant propagation (leaf and stem cuttings). Throughout the year, plants are produced there for the exhibition greenhouses, the Garden boutique and seasonal exhibitions as Halloween.
For each plant displayed in the exhibition greenhouses, three plants are grown in the service greenhouses. Complex B, opened in 1991, consists of the greenhouses where the Garden’s largest collections are housed (Orchids, Cacti, Ferns, etc.). They are equipped with a computer system that automatically deploys blinds, opens windows and controls the temperature and humidity levels and ventilation, all according to data transmitted by a weather station.
The Jardin botanique, Insectarium, Biodôme and Institut de recherche en biologie végétale (IRBV) share the greenhouses in complex C, which opened in 1993. The Institute does some of its research there, in botany, ecology and molecular biology. The Insectarium grows plants to feed the insects it houses in vivariums, butterfly tents, etc. The greenhouses used by the Biodôme have to recreate different climates: hot zones for tropical plants and cold zones for plants from the Laurentian Maple Forest. It also has basins for maintaining tropical aquatic plants. The Jardin botanique uses two of these greenhouses to produce potted flowering plants and to store baskets from its Begoniaceae and Gesneriads collection.
Louis Dupire greenhouses
The Louis Dupire greenhouses are a vast 2,720 m2 complex in the northwest corner of the Garden, at the corner of Rosemont and Pie IX Boulevards. From 1959 to 2006 they were used for producing annuals for the city’s urban beautification programs. The École des métiers de l'horticulture de Montréal is to take over the facilities once they have been renovated. The Garden uses some space in these greenhouses to grow annuals and vegetable plants.
The horticulturists responsible for our gardens and collections can rely on a colleague specializing in propagation, who produces the plants needed for enhancing their collections. Two tree trimmers trained in the latest arboriculture techniques care for all the trees in the Garden on a seasonal basis. The team also includes a horticulturist specialized in installing and maintaining irrigation systems. These systems, connected to weather stations, allow us to manage our water use more closely and efficiently. In the greenhouses, specialized horticulturists are responsible for watering the plants, seven days a week. They adjust the frequency to the specific needs of each collection, the season and outdoor temperatures.
An insect-proof greenhouse for the Insectarium
The ventilation system of the greenhouses in complex C was designed to be insect proof. Higher air pressure inside the greenhouse prevents insects from entering and expels any that are inside. For even more effective control, the roof vents are kept closed and the side windows are covered with a Nytex insect screen. Needless to say, biological pest control is essential to eliminate any insects that do make their way inside despite the ventilation system. All these precautions make it possible to grow host and nectar-producing plants for raising insects, without any need for pesticides.
The greenhouses are heated with a hot-water system. The central computer records water temperatures minute by minute; when the temperature in one of the greenhouses rises or falls, the computer adjusts the hot water flow. The temperature in each greenhouse can be adjusted to within half of one degree centigrade.
Water treatment in the mechanical room
Water is vital to our operations, since it feeds the heating, irrigation and misting systems in all the greenhouses. The water from the city pipes has to be treated before being sent into the 11 km of piping running beneath the greenhouses, however. It is warmed and acidified or demineralized, depending on the specific needs of each collection.