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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Greenhouse | 1/4 | https://en.wikipedia.org/wiki/Greenhouse | reference | science, encyclopedia | 2026-05-05T09:02:41.007301+00:00 | kb-cron |
In horticulture, a greenhouse is a structure designed to regulate the temperature and humidity of the environment inside it with a view to growing plants. There are different types of greenhouses, but they all have large areas covered with transparent materials that let sunlight enter and that inhibit the loss of the sun's heat. The most common materials used in modern greenhouses for walls and roofs are rigid plastics made of polycarbonate, plastic film made of polyethylene, or glass panes. When sunlight shines into a greenhouse the temperature inside increases, providing a sheltered environment for plants to grow — even in cold weather. The terms greenhouse, glasshouse, and hothouse often refer interchangeably to buildings used for cultivating plants. The specific term used depends on the material and on the heating-system used in the building. Nowadays, greenhouses are more commonly constructed with a variety of materials, such as wood and polyethylene plastic. A glasshouse, on the other hand, is a traditional type of greenhouse which uses glass panes that allow light to enter. The term hothouse indicates the use of artificial heating. However, both heated and unheated structures can generally class as greenhouses.
The word "vinery", when referring to a site for growing grapevines, may reference either a hothouse or a glasshouse. Greenhouses can range in size from small sheds to industrial-sized buildings and colossal glasshouses. The smallest example is a miniature greenhouse known as a cold frame, typically used at home (compare cloche). Large commercial greenhouses are high-tech production-facilities used to grow vegetables, flowers or fruits. Such glass greenhouses may feature extensive equipment, including screening, heating, cooling, and lighting installations, sometimes controlled by a computer to optimize conditions for plant growth. Different techniques manage growing conditions (including air temperature, relative humidity and vapour-pressure deficit) in order to provide the optimum environment for cultivation of a specific crop.
== History ==
=== Roman Empire === Before the development of greenhouses, agricultural practices were constrained to weather conditions. According to the climatic zone of communities, people were limited to a select range of species and time of the year in which they could grow plants. Yet around 30 CE, the Roman Empire built the first recorded attempt of an artificial environment. Due to emperor Tiberius's declining health, the royal physicians recommended that the emperor eat one cucumber a day. Cucumbers, however, are quite tender plants and do not grow easily year-round. Therefore, the Romans designed an artificial environment, like a greenhouse, to have cucumbers available for the emperor all year. Cucumbers were planted in wheeled carts which were put in the sun daily, then taken inside to keep them warm at night. The cucumbers were stored under frames or in cucumber houses glazed with either oiled cloth known as specularia or with sheets of selenite (a.k.a. lapis specularis), according to the description by Pliny the Elder.
=== 15th-century Korea === The next biggest breakthrough in greenhouse design came from Korea in the 15th century during the Joseon dynasty. In the 1450s, Soon ui Jeon described the first artificially heated greenhouse in his manuscript called Sangayorok. Soon ui Jeon was a physician to the royal family, and Sangayorok was intended to provide the nobility with important agricultural and housekeeping knowledge. Within the section of agricultural techniques, Soon ui Jeon wrote how to build a greenhouse that was able to cultivate vegetables and other plants in the winter. The Korean design adds an ondol system to the structure. An ondol is a Korean heating system used in domestic spaces, which runs a flue pipe from a heat source underneath the flooring. In addition to the ondol, a cauldron filled with water was also heated to create steam and increase the temperature and humidity in the greenhouse. These Korean greenhouses were the first active greenhouses that controlled temperature, rather than only relying on energy from the sun. The design still included passive heating methods, such as semi-transparent oiled hanji windows to capture light and cob walls to retain heat, but the furnace provided extra control over the artificial environment. The Annals of the Joseon Dynasty confirm that greenhouse-like structures incorporating ondol were constructed to provide heat for mandarin orange trees during the winter of 1438.
=== 17th century === The concept of greenhouses also appeared in the Netherlands and then England in the 17th century, along with the plants. Some of these early attempts required enormous amounts of work to close up at night or to winterize. There were serious problems with providing adequate and balanced heat in these early greenhouses. The first 'stove' (heated) greenhouse in the UK was completed at Chelsea Physic Garden by 1681. Today, the Netherlands has many of the largest greenhouses in the world, some of them so vast that they are able to produce millions of vegetables every year.
Experimentation with greenhouse design continued during the 17th century in Europe, as technology produced better glass and construction techniques improved. The greenhouse at the Palace of Versailles was an example of their size and elaborateness; it was more than 150 metres (490 ft) long, 13 metres (43 ft) wide, and 14 metres (46 ft) high.
=== 18th century === Andrew Faneuil, a prosperous Boston merchant, built the first American greenhouse in 1737.
When returning to Mount Vernon after the war, George Washington learned of the greenhouse built at the Carroll estate of Mount Clare (Maryland). It was designed by Margaret Tilghman Carroll, an industrious gardener who cultivated citrus trees in this orangery. In 1784 Washington wrote requesting details about the design of her greenhouse, and she complied. Washington wrote: