Greenhouse

Greenhouses are purpose-built structures designed to create controlled environments in which plants can be cultivated throughout the year. They function by regulating temperature, humidity and light, enabling the growth of species that might otherwise be limited by climatic conditions. Although their design and materials have evolved significantly over time, the fundamental aim remains the same: to provide a stable, protected and productive growing space.

Definition and Purpose

A greenhouse is typically constructed with large expanses of transparent or translucent material that allow sunlight to enter while retaining heat. When solar radiation passes through the covering, the internal temperature rises, creating a sheltered microclimate suitable for plant growth, even in colder seasons. Modern greenhouses commonly use glass panes, rigid polycarbonate sheeting or polyethylene film as construction materials. These contribute to effective light transmission, insulation and weather protection.
Terminology varies: glasshouse refers to a structure built entirely of glass, while hothouse generally denotes an artificially heated greenhouse, though both heated and unheated versions broadly fall under the term greenhouse. Sizes range from small domestic cold frames to industrial-scale complexes used for commercial agriculture, where sophisticated climate-control systems regulate temperature, humidity and vapour-pressure deficit. Many commercial facilities employ automated screening, heating, cooling, ventilation and lighting systems, often managed by computer to optimise growth conditions for crops such as vegetables, fruits and cut flowers.

Materials and Structural Features

The construction of a greenhouse depends on the intended use, budget and environmental conditions. Common features include:

• Transparent cladding such as glass, polycarbonate or polyethylene film to maximise light exposure.
• Support frames made of aluminium, steel, timber or composite materials, chosen for their strength and resistance to corrosion.
• Environmental control systems that may include heaters, fans, evaporative coolers, misting units and automated vents.
• Supplementary lighting, especially in high-latitude regions, to extend the photoperiod and promote growth.
• Insulation measures such as double-layer coverings or thermal screens to reduce heat loss in colder months.

Domestic greenhouses often prioritise simplicity and affordability, while commercial models are engineered for high productivity and energy efficiency.

Early Developments in the Roman Empire

The earliest known attempts to create controlled growing environments can be traced to the Roman Empire around 30 CE. Agricultural activity at the time was strongly constrained by weather and seasonal variations, limiting what could be grown and when. According to historical accounts, Emperor Tiberius was advised to consume a cucumber daily for health reasons. As cucumbers were delicate plants unsuited to year-round cultivation, Roman gardeners devised an ingenious solution: the plants were grown in wheeled containers that were pushed into sunlight by day and moved indoors at night for warmth. The containers were kept under frames or inside structures glazed with oiled cloth (specularia) or thin sheets of the mineral selenite. These early constructions represent a precursor to the modern greenhouse, demonstrating an understanding of the need to moderate environmental conditions for plant cultivation.

Advances in 15th-Century Korea

A major innovation in greenhouse design emerged in 15th-century Korea during the Joseon dynasty. In the 1450s, the royal physician Soon-ui Jeon documented the first artificially heated greenhouse in the Sangayorok, a manual on agricultural and household knowledge intended for the nobility. This advanced design incorporated the ondol, a traditional Korean under-floor heating system in which heat from a furnace travelled through flues beneath the structure. A cauldron was additionally heated to produce steam, increasing humidity and warmth within the space.
These greenhouses were the first active, independently heated systems, no longer relying solely on passive solar energy. They used semitransparent oiled paper windows to admit light and earthen walls to retain heat. Records from the Annals of the Joseon Dynasty note that similar structures were built to provide winter protection for mandarin orange trees as early as 1438. This development marks a significant step towards controlled-environment agriculture.

Developments in 17th-Century Europe

Greenhouse concepts re-emerged in Europe in the 17th century, particularly in the Netherlands and England, where interest in exotic plants grew rapidly. Early European greenhouses were often difficult to manage, especially in terms of achieving balanced, reliable heating. Many required substantial labour to enclose or insulate them during cold periods. Nevertheless, improvements in glass production and construction techniques gradually facilitated more ambitious designs.
By 1681, the first stove-heated greenhouse in Britain had been completed at the Chelsea Physic Garden. The Netherlands later became a global leader in greenhouse cultivation, developing some of the world’s largest commercial facilities capable of producing millions of vegetables annually.
The greenhouse at the Palace of Versailles exemplified the scale and sophistication of early European glass structures. It was renowned for its imposing dimensions and elaborate design, indicating an increasing desire to cultivate a diversity of plants beyond the limits of local climate.

Expansion in the 18th Century

Greenhouse construction spread to North America during the 18th century. The first American greenhouse was built in Boston in 1737 by the merchant Andrew Faneuil. Interest among landowners and botanists grew steadily. In 1784, George Washington sought design details for an orangery at Mount Vernon after learning of similar structures on the Carroll estate in Maryland. Such edifices were used to overwinter citrus and other tender species, reinforcing the greenhouse’s role in expanding botanical possibilities.

Nineteenth-Century Innovations

The 19th century saw remarkable advancements in greenhouse architecture, technology and purpose. Charles Lucien Bonaparte is often credited with constructing one of the first practical modern greenhouses in Leiden during the early 1800s, designed for growing tropical medicinal plants. As botany developed academically, glasshouses spread to universities and scientific institutions. French designers referred to early structures as orangeries, used primarily to protect citrus trees, while pineries were developed for pineapple cultivation.
During the Victorian era in Britain, greenhouse construction reached unprecedented levels of sophistication. Colonial expansion fuelled a passion for collecting exotic plants, and glasshouses became public attractions that displayed curated botanical specimens. These structures often symbolised imperial authority by showcasing flora from different colonies, reinforcing the perception of British control over global environments.
Large palm houses became characteristic of the period, offering sufficient height for tall tropical species. Advances in iron and glass enabled expansive internal spaces without heavy structural supports, an architectural innovation also applied to railway stations, market halls and exhibition buildings.
Notable examples include:

• The palm house at Belfast Botanic Gardens, completed in 1840 and designed by Charles Lanyon.
• The Palm House at the Royal Botanic Gardens, Kew, completed in 1848 and constructed by Richard Turner.
• Earlier inspirations such as the vast glasshouse at Chatsworth House (1837–40).
• The Crystal Palace (1851), one of the most iconic glass-and-iron structures of the era, though now lost.

These achievements illustrate how greenhouses evolved not only as functional growing spaces but also as architectural and cultural landmarks.

Modern Greenhouse Applications

Contemporary greenhouses serve a wide range of purposes, from small domestic garden units to highly engineered commercial production systems. High-tech facilities use integrated climate-control technologies to manage temperature, humidity, CO₂ levels and lighting. Such systems allow precise regulation of conditions to optimise yield, quality and efficiency.
Modern applications include:

• Commercial horticulture, particularly the cultivation of tomatoes, cucumbers, peppers, berries and ornamental plants.
• Research, where controlled variables support studies in plant physiology, genetics and environmental science.
• Public botanical gardens, which use glasshouses to display tropical, arid or specialised plant collections.
• Urban agriculture, including rooftop greenhouses and vertical farming units.