A Look Back at the Amazing History of Greenhouses

Vertical farms may be making all the headlines in the indoor farming world these days, but it might surprise you to learn that these high-tech installations are still a relatively small player in the controlled environment agriculture (CEA) landscape. According to the 2017 State of Indoor Farming report from Agrilyst, despite the hype around vertical farming, CEA is still dominated by a type of growing facility that is more than 2,000 years old: the greenhouse.

Given their remarkable longevity, it’s perhaps not surprising that greenhouses in one form or another still make up nearly 50% of indoor growing installations. And while today’s greenhouses are, of course, outfitted with the latest growing technology, it’s interesting to note that in many ways, they are not so different from their predecessors of centuries ago. To learn more, read on for a look back at some key moments in greenhouse history.

Greenhouses in Roman times

Most historians credit those famous engineers and innovators, the ancient Romans, with the development of the first greenhouse. According to scholars, it was around the year 30 AD that royal physicians recommended that the ailing emperor Tiberius eat one cucumber a day to restore his health. This was not a problem in summer, when cucumbers could grow easily in the heat, but to be able to produce the vegetable year-round, an alternative solution was needed. In response, gardeners and engineers of the era created growing structures that resembled small carts with roofs of a translucent material — a thin, oiled cloth or a sheet of selenite, the crystal form of the mineral gypsum. These materials would allow sunlight in while preventing heat from escaping.

Medieval developments in Italy and Korea

The next significant developments in greenhouse history took place more than a thousand years after the earliest examples were invented by the Romans. Around the 13th century, the Italians were developing the world’s first botanic gardens to house and display the tropical plants and vegetables that early explorers were bringing back from their travels. One of the earliest botanic gardens was located at the Vatican, although, unfortunately, it no longer exists. A few centuries later, there is recorded evidence that greenhouses were undergoing significant development in countries like Korea: written references describe the creation of temperature-controlled glasshouses that were used to grow citrus fruits during the cold winter months.

A greenhouse Renaissance

The early days of the Renaissance — from the 16th century and onward — saw greenhouses becoming more widespread all over Europe. Thanks to technological advances of the time, greenhouses during this period benefitted from better quality glass and metal, which made construction easier and more durable. At the same time, the aristocratic classes in countries like England, France, the Netherlands, and Italy were developing a taste for foreign plants and exotic fruits like oranges and pineapples. As a result, greenhouses soon became a must-have status symbol on wealthy estates. One of the most famous greenhouse examples from this era is the great glasshouse, or orangerie, at the Palace of Versailles, which was commissioned by Louis XIV in 1661.

The birth of the modern greenhouse

While greenhouses continued to be favored by the wealthy, as well as by universities, scientific institutions, and governments, well into the 19th century, it was the Industrial Revolution that made greenhouses more accessible to the growing middle class, particularly in England. At this time, the cost of producing glass dropped dramatically, and the hefty tax on glass and windows was abolished. This led to the construction of some of the most magnificent greenhouses that still survive today, such as the Palm House at Kew Gardens just outside London. In addition, smaller, self-assembled greenhouses began to pop up in the gardens of middle-class homes.

Greenhouses in the 20th century

The early- and mid-20th century brought many more exciting developments to the greenhouse landscape. In terms of materials, more greenhouses started to incorporate aluminum framing rather than the previously-used iron or steel: this innovation allowed greenhouses to be more lightweight and better able to withstand rust. The conservatory at the US Botanic Garden in Washington, DC, built in the 1930s by Lord & Burnham, is one of the earliest examples of this kind of construction.

Beyond new materials, this period also ushered in changes to the growing techniques used in greenhouses. Specifically, greenhouses in the early- and mid-20th century moved from soil-based to hydroponic systems, in which the plants are grown without soil and instead receive nutrients from a solution applied directly to their roots. Based on growing methods that can be traced back thousands of years, hydroponic technology emerged as a viable method for growing crops in the early 1900s, but it was during World War II that the technique truly took off. At this time, Allied forces turned to hydroponics to ensure that their troops, stationed in remote areas all over the globe, could produce their own fresh food. During these years, military hydroponic greenhouses were built all over the world, and the new era of the modern hydroponic greenhouse, geared toward growing at scale, was definitively launched.