Greenhouse
A building of glass or clear plastic where plants are grown in controlled warmth and light.
Also: glasshouse
A greenhouse traps the sun's heat and keeps out wind, frost and heavy rain. Inside, growers can control temperature, humidity, light and feeding. A large share of the world's cut roses, gerberas, chrysanthemums and orchids is grown under cover, from heated glass in the Netherlands to plastic-roofed houses in the highlands of Kenya, Ethiopia, Colombia and Ecuador, where the climate itself does much of the work. Home gardeners use small ones to raise seedlings.