How does a greenhouse work?

Question

How does a greenhouse work?

Answer 1

Britannica Concise Encyclopedia: greenhouse

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.

Columbia Encyclopedia: greenhouse

enclosed glass house used for growing plants in regulated temperatures, humidity, and ventilation. A greenhouse can range from a small room carrying a few plants over the winter, to an immense heated glass building called a hothouse or conservatory, covering acres of ground and used for forcing fruits or flowers out of season. Greenhouses have long been used for holding plants over cold seasons and for growing tropical plants and less hardy fruits, but only in this century has the greenhouse been used for forcing vegetables. Now millions of dollars' worth of plant products are raised yearly in greenhouses.

Gardener's Dictionary: greenhouse

A structure, covered with glass, fiberglass, or plastic, in which temperature and humidity can be controlled, for the cultivation and/or protection of plants.

Wikipedia: greenhouse

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; it heats up because incoming solar radiation from the sun warms plants, soil, and other things inside the building. Air warmed by the heat from hot interior surfaces is retained in the building by the roof and wall. These structures range in size from small sheds to very large buildings.

The glass used for a greenhouse works as a selective transmission medium for different spectral frequencies, and its effect is to trap energy within the greenhouse, which heats both the plants and the ground inside it. This warms the air near the ground, and this air is prevented from rising and flowing away. This can be demonstrated by opening a small window near the roof of a greenhouse: the temperature drops considerably. This principle is the basis of the autovent automatic cooling system. Greenhouses thus work by trapping electromagnetic radiation and preventing convection. Miniature greenhouses are known as a cold frame.

Uses

Greenhouse effects are often used for growing flowers, vegetables, fruits, and tobacco plants. Bumblebees are the pollinators of choice for most greenhouse pollination, although other types of bees have been used, as well as artificial pollination.

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Answer 2

the above answer is corrsect, but in easy to understand terms, it reflects the heat from the suns rays back towards tha plants and lets them grow allot faster!