A greenhouse is a structure in which the walls and roof are made mainly of transparent materials such as glass. Greenhouses are the structures in which plants that require climatic regulation are grown. They can range in size from small sheds to large industrial sized buildings. Because of the transparent material, greenhouses that are exposed to sunlight become significantly warmer than the outside temperature. This protects delicate plants from cold weather. Commercial greenhouses in particular are quite high tech and are often filled with equipment that can be controlled by a computer in order to create the perfect conditions for plant growth.
Greenhouses work due to solar radiation. Simply put, ultraviolet light, and heat passes through the greenhouse walls and roof. The heat and light is then unable to escape the greenhouse, causing it to warm up. This process is sometimes referred to as the greenhouse effect. Heating, ventilation, and carbon dioxide enrichment are all important components for a successful greenhouse.
There are two main types of greenhouses including glass and plastic. In domestic greenhouses, thin, horticultural glass is normally used and is not as clear as glass used for many windows. For plastic greenhouses, something called PMMA acrylic glass is normally used. The acrylic glass consists of polyethylene film and sheets of polycarbonate material. One of the largest greenhouses in the world covers almost fifty thousand acres and is located in Almeria, Andalucia, Spain.
Greenhouses are used because they allow for better control of the growing environment for many types of plants. Depending on the intricacy of a greenhouse, many factors can be controlled including levels of shade and light, temperature, humidity, fertilizer application, and irrigation. Greenhouses can also sometimes be used to overcome growing issues on land. Areas with poor light levels or short growing seasons can really benefit from the use of a greenhouse.
Greenhouses also play an important role in food supply, as they allow certain crops to be grown year round to keep up with demand. Greenhouses can be used to grow not only food such as vegetables and fruits but also flowers and transplants. Often, vegetables can be placed in greenhouses in the late winter and early spring months, and then transferred outside when the weather permits. Bees are often used in greenhouses for pollination purposes although hydroponics and artificial pollination are also options.
While greenhouses have a number of benefits, they do require more management and maintenance compared to outdoor growing. Diseases and pests can become an issue in greenhouses due to the high heat and humidity so it is important to control these elements to prevent issues.
The idea of growing plants in a controlled environment has been in existence since Roman times. Roman gardeners would use similar methods to those used in greenhouses. While they did not have specific structures, they would place plants in wheeled carts so that they could be placed in the sun each day. The carts would then be brought inside at night to keep the plants warm. Actual greenhouses did not appear until the 13th century and they were built in Italy to house exotic plants. Active greenhouses, or those in which the temperature can be decreased or increased manually, did not appear until a far later date, thought to be around 1450 AD in Korea. Greenhouses began to appear in England and the Netherlands in the 17th century with early models requiring tons of work to maintain. Today, the Netherlands is home to some of the largest greenhouses in the world. Greenhouses continued to become more widely used over time. Charles Lucien Bonaparte, a French botanist, is most often given credit for building the first modern greenhouse in the 1800s in Leiden, Holland.
Written By Ava Rose.