Whilst studying for my Diploma in Horticulture, I covered quite a lot of information on the theme of garden history, from The Garden of Eden, Islamic gardens, Monastic gardens, through to modern times, but never touched on Greenhouses throughout history. So, I thought I might do a little bit of research into the fascinating topic of the origins of the greenhouse.

 

The first greenhouses

I was quite surprised to discover that the first recorded notes on growing plants under cover date back as far as the Romans in around 30AD. Apparently, Emperor Tiberius was instructed by the royal physicians to eat a cucumber a day, in order to improve his health. (Cucumber is a natural diuretic, as it helps to remove excess water from the body). The said cucumbers would grow well during the warm Italian summers but for the emperor to receive his daily dose, they needed an all-year solution. Being the genius inventors that the Romans were, they came up with idea of building cart-like structures with translucent roofs. These roofs were made from a sheet of mineral selenite, which is the crystal form of gypsum. These structures allowed the sun to warm the plants whilst protecting them from the winter’s elements. In the same century, The Roman Philosopher Lucius Seneca also wrote that People wanted roses in bloom through winter. Shiploads of rose plants were being brought in from the warmer climates of Alexandria to keep the Roman citizens happy. These were protected in much the same way as the medicinal cucumbers, with some of the early greenhouses being warmed by hot air to encourage flowering.

There is a reference to large glass houses in 13^th century Italy, where citrus trees were moved inside during the winter months.  During the 14^th century at the time of the Joscon Dynasty, records showed that the Koreans were using a traditional structure to protect tangerine trees, where both climate and temperature could be controlled.

 

The predecessors of the modern greenhouse

The predecessors of the modern greenhouse arrived first in Holland and then in England in the 17^th century. The first greenhouses were mostly built of timber and then later from stone and brick. They were called greenhouses as they protected the “greens”. Which was the name given to tender plants. These structures were constructed with only a few windows to allow in light, and these were normally placed on the south facing elevation.  The amount of glass was restricted during this period, as glass was very expensive, was subject to tax and the technology of the time only allowed for the manufacture of small sized sheets.

Greenhouses became larger, with an increase in the amount of glass used, as plant hunters travelled the world and returned with more exotic plants, which needed protecting from the colder climate of the Northern Hemisphere. These plants were not only highly fashionable but valuable as well. With the desire to protect and admire these plants the greenhouse structure moved nearer to the main house, and eventually in the late 18^th century these structures were built onto the external wall of the house itself.  In 1782 The European Magazine quoted, “that the idea of a conservatory opening through a folding door to the salon, was too fine an idea to be left unfinished”. In the 17^th century, the term conservatory was used for anything that required conserving, including food and ice, etc. It was through the conservation of plants that the modern term conservatory as we now know it was coined.

Greenhouses really started to develop in the early 19^th century when the window tax was lifted, and technological advances meant that larger sheets of glass could be manufactured. What we now call greenhouses, which was the 17^th century name, became known as glasshouses.

 

The first greenhouse heating

Technology for heating the greenhouse also advanced. The early greenhouses of the 17^th century sometimes had a fire lit in them on very cold nights. The very large glasshouses of the 18^th century had arched fireplaces built into the foundations of the structure, where fires were lit during cold weather with the heat travelling into the glasshouse via ducts. It wasn’t unknown for the fumes to kill the plants or even for the plant house to burn down. The first piped hot air or water was introduced into the glasshouse in the 1820’s.

 

A piece of history

This photo was taken at one of my client’s gardens. Even though the roof of this planthouse is long gone, you can clearly see the large pipes that were used to carry warm air or water into the building. This building houses a large vine that has managed to thrive despite the lack of heat or even a roof. There was another building adjacent to the planthouse which has completely collapsed now but the boiler, used to generate the heat is still there. Outside the main planthouse, the tops of arches can be seen, which I believe may have been external fireplaces which were used before the piped system was introduced. The main house of this property is rather grand and built in 1820. It includes sixteen acres, with two large walled gardens and used to employ nine gardeners. There was this collapsed planthouse and another very large lean too greenhouse, plus a large conservatory with a sunken pond. 

 

Popular pineapples 

In the 18^th century the pineapple became the most expensive and fashionable dessert to be served at the table of the nobles and gentry and was not only a sign of their wealth but also demonstrated the skill of their gardeners. Pineapple plants could sell for up to the equivalent of £5 k in today’s money, and with the desire to show off to their contemporaries the wealthy spared no expense in developing their greenhouses to accommodate fruit and vegetables from all the corners of the globe. Their head gardeners increased their skills whilst some poorly paid lad was employed to keep the heaters working both day and night.