A greenhouse is a building in which plants are grown. These structures range in size from small sheds to very large buildings. A miniature greenhouse is known as a cold frame

Cold frame

In agriculture and gardening, a cold frame is a transparent-roofed enclosure, built low to the ground, used to protect plants from cold weather. The transparent top admits sunlight and prevents heat escape via convection that would otherwise occur, particularly at night...

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A greenhouse is a structure with different types of covering materials, such as a glass or plastic roof and frequently glass or plastic walls; it heats up because incoming visible solar radiation (for which the glass is transparent) from the sun is absorbed by plants, soil, and other things inside the building.