Historically, humans have always tried to find a means to make nature adapt to our own needs; whether it’s cultivating a crop or plant that can be grown in cooler climates, or finding ways to prolong the growing season, it seems that we’ve always been predisposed to make the most of nature’s ‘best bits’.
So it’s not surprising to learn that one of the earliest pioneering civilisations, the Romans, were amongst the first cultures to use an incarnation of the greenhouse, the ‘specularium’. It is thought that fires were kept burning outside the buildings to create the necessary temperature inside. Around 30AD, Pliny the Elder described how the Roman Emperor Tiberius commissioned the first types of greenhouses to protect and promote the growth of the cucumber-like plants that his physicians had prescribed him. Although glass had not yet been invented at this time, translucent sheets of mica were placed on the specularium roof, allowing the specularia plants, flowers and vegetables to thrive inside.
However, after the fall of the Roman Empire, many of these revolutionary horticultural techniques were forgotten, until a 13th century Dominican friar and scholar named Albertus Magnus uncovered some Roman documents and writings on their horticultural findings. Thus a new generation of hothouses, or ‘giardini botanici’ (botanical gardens) began to appear in Italy at this time, where plants and flowers were ‘forced’ much earlier than the usual growing season. These kind of early greenhouses began to spring up all over Europe, becoming more commonplace in universities and stately homes, where plants brought back from the ‘New World’ were studied, cultivated or simply displayed.
Around the 16th century, the French version of the greenhouse became known as the ‘orangery’. As the name suggests, these greenhouses were used to protect the orange trees from the relatively harsh European winters. As pineapples became much more en vogue, the orangeries also became known as pineapple pits or ‘pineries’. In addition to their practical use, orangeries were often built as a status symbol, indicating wealth and grandeur.
To begin with, many orangeries were built from sturdy wooden frames, with a stone or brick wall, and solid roof. Glass was not as abundant in the design of these hothouses, as there was a sizeable tax applicable to glass at this time. The 17th century saw much experimentation with greenhouse design, and the efficiency with which the plants were grown – many were heated by furnaces or even built into a pit, and heated by the south facing windows. In England, what is now the Oxford University Botanic Garden, a slated roof greenhouse was built, heated by fire baskets of charcoal, and later the first wooden-framed glasshouse also appeared on this site.
Elsewhere, features such as heat flues and angled glass walls began to appear, but it wasn’t until the glass tax was relieved in the 19th century that the ‘glasshouses’, from which our modern greenhouses were borne, began to become a more familiar sight. During this time, engineering that allowed for strong, durable and intricate ironwork was being pioneered, and so iron-framed glasshouses eventually began to replace the stone walls and wooden frames of the orangeries.
As greenhouses became more prevalent in wealthy homes and establishments across Europe, they became an increasingly intricate and ostentatious in design. Some truly magnificent greenhouses were constructed during this time, including the conservatory at Kew Gardens and the Crystal Palace in London, built for the Great Exhibition in 1851.
The mid twentieth century saw the introduction of the first mass-manufactured lower-cost greenhouses. These included the galvanised and aluminium framed structures that are so widespread in our gardens today. Features such as auto-vents and floor heating have also been introduced, as technologies have developed, and costs reduced.
During the 1960s, hoop houses also became more commonplace, as they offered a significantly cheaper way to construct a warm microclimate for growing plants and vegetables. These hoop houses were constructed using polyethylene film stretched over several steel tubing, frames or PVC water pipes – the forerunner of our modern polytunnels.
In recent years, the geodesic dome design of the Eden Project in Cornwall, has become accepted as a new direction of greenhouse design. The hexagonal structures that make up the geodesic dome are clad with UV-transparent ETFE, and the structures are completely self-supporting, with no internal supports. The environmental controls systems are run and maintained by computers.