/green"hows'/, n., pl. greenhouses /-how'ziz/.a building, room, or area, usually chiefly of glass, in which the temperature is maintained within a desired range, used for cultivating tender plants or growing plants out of season.[1655-65; GREEN + HOUSE]
* * *Building designed for the protection of tender or out-of-season plants against excessive cold or heat.Usually a glass-or plastic-enclosed structure with a framing of aluminum, galvanized steel, or such woods as redwood, cedar, or cypress, it is used for the production of fruits, vegetables, flowers, and any other plants requiring special temperature conditions. It is heated partly by the sun and partly by artificial means. This controlled environment can be adapted to the needs of particular plants.
* * *also called Glasshouse,building designed for the protection of tender or out-of-season plants against excessive cold or heat. In the 17th century greenhouses were ordinary brick or timber shelters with a normal proportion of window space and some means of heating. As glass became cheaper and as more sophisticated forms of heating became available, the greenhouse evolved into a roofed and walled structure built of glass with a minimal wooden or metal skeleton. By the middle of the 19th century, the greenhouse had developed from a mere refuge from a hostile climate into a controlled environment, adapted to the needs of particular plants. A huge increase in the availability of exotic plants in the 19th century led to a vast increase in glasshouse culture in England.The modern greenhouse is usually a glass- or plastic-enclosed framed structure that is used for the production of fruits, vegetables, flowers, and any other plants that require special conditions of temperature. The basic structural forms are the span-type greenhouse, which has a double-sloped, or A-shaped, roof, and the lean-to greenhouse, which has only one roof slope and leans against the side of a building. Two or more span-type greenhouses are sometimes joined side by side so that they have fewer external walls, and heating costs are consequently less. A greenhouse has a large expanse of glazing on its sides and roof so that the plants are exposed to natural light for much of the day. Glass has been the traditional glazing material, but plastic films, such as polyethylene or polyvinyl, and fibreglass are increasingly used. The framing of the structure is made of aluminum, galvanized steel, or such woods as redwood, cedar, or cypress. A greenhouse is heated partly by the rays of the Sun and partly by artificial means, such as circulating steam, hot water, or hot air. Because a greenhouse can become too hot as well as too cold, some type of ventilating system is also needed; this usually consists of roof openings, which can be operated mechanically or automatically, and end-wall openings, through which electric fans draw air and circulate it throughout the interior.The plants grown in greenhouses fall into several broad categories based on their temperature requirements during nighttime hours. In a cool greenhouse, the nighttime temperature falls to about 45°–50° F (7°–10° C). Among the plants suited to cool greenhouses are azaleas, cinerarias, cyclamens, carnations, fuchsias, geraniums, sweet peas, snapdragons, and a variety of bulbous plants including daffodils, irises, tulips, hyacinths, and narcissi. A warm greenhouse has nighttime temperatures of 50°–55° F (10°–13° C). Begonias, gloxinias, African violets, chrysanthemums, orchids, roses, Boston ferns, coleuses, and many kinds of ferns and of cacti and other succulents are suited to such temperatures. In a tropical greenhouse, or hothouse, which has nighttime temperatures of 60°–70° F (16°–21° C), caladiums, philodendrons, begonias, gardenias, poinsettias, bougainvilleas, passionflowers, and many kinds of palms and orchids can be grown. In Great Britain and other countries with cool climates, commercial greenhouses grow tomatoes and other warm-weather vegetables. See also conservatory.
* * *
Look at other dictionaries:
greenhouse — [grēn′hous΄] n. a building made mainly of glass, in which the temperature and humidity can be regulated for the cultivation of delicate or out of season plants adj. of or contributing to the greenhouse effect [greenhouse gases] … English World dictionary
greenhouse — 1660s, from GREEN (Cf. green) + HOUSE (Cf. house). Greenhouse effect attested from 1937 … Etymology dictionary
Greenhouse — Green house , n. A house in which tender plants are cultivated and sheltered from the weather. [1913 Webster] … The Collaborative International Dictionary of English
greenhouse — ► NOUN ▪ a glass building in which plants that need protection from cold weather are grown … English terms dictionary
Greenhouse — [ thumb|250px|A greenhouse in Saint Paul, Minnesota.] A greenhouse (also called a glasshouse or hothouse) is a building where plants are cultivated. A greenhouse is a structure with a glass or plastic roof and frequently glass or plastic walls;… … Wikipedia
greenhouse — [[t]gri͟ːnhaʊs[/t]] greenhouses 1) N COUNT A greenhouse is a glass building in which you grow plants that need to be protected from bad weather. 2) ADJ: ADJ n Greenhouse means relating to or causing the greenhouse effect. ...the consequences of… … English dictionary
greenhouse — I. noun Date: 1664 1. a structure enclosed (as by glass) and used for the cultivation or protection of tender plants 2. a clear plastic shell (as a canopy) covering a section of an airplane; also a compartment (as for a bombardier) enclosed by… … New Collegiate Dictionary
greenhouse — n. a light structure with the sides and roof mainly of glass, for rearing delicate plants or hastening the growth of plants. Phrases and idioms: greenhouse effect the trapping of the sun s warmth in the lower atmosphere of the earth caused by an… … Useful english dictionary
greenhouse — UK [ˈɡriːnˌhaʊs] / US [ˈɡrɪnˌhaʊs] noun [countable] Word forms greenhouse : singular greenhouse plural greenhouses a building made of glass that is used for growing plants that need protection from the weather … English dictionary
greenhouse — /ˈgrinhaʊs / (say greenhows) noun 1. a building, chiefly of glass, for the cultivation or protection of plants. –adjective 2. of or relating to the greenhouse effect: greenhouse issues … Australian English dictionary