Greenhouse technology has come a long way since the time of the ancient Romans, but the concept -- an enclosed structure providing a special environment for plants -- is essentially the same today. Gardeners use these structures to protect plants from heat or cold, to extend a plant’s growing season or to foster non-native plants.

The Roman emperor’s cucumber experiment was referenced some half a millenium later by Thomas Hill, author of the first popular gardening book in English. He gives his readers practical advice on protecting spring seedlings in a coldframe-type structure until the weather is reliably warm:

“The young plants may be defended from cold and boisterous windes, yea, frosts, the cold aire, and hot Sunne, if Glasses made for the onely purpose, be set over them, which on such wise bestowed on the beds, yeelded in a manner to Tiberius Caesar, Cucumbers all the year, in which he took great delight...”

Thomas Hill, “The Gardener’s Labyrinth”, 1577

New Exotics and the Study of Botany
The Italians built the first modern greenhouses. These “giardini botanici,” or botanical gardens, housed new and unusual species brought home by explorers. The plants, along with the structures required to protect
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Jardin d'Hiver, Paris
them, soon gained popularity in Holland and England. Temperature regulation for these indoor plants remained problematic for early greenhouse keepers.

The English often referred to their greenhouses as “conservatories.” Both the English and the French aristocracy had become fond of newly-discovered tropical fruits, so they commissioned “orangeries” and “pineries,” greenhouses especially developed to cultivate orange trees and pineapple plants. Of course, a special enclosure devoted to the cultivation of exotic plants remained prohibitively expensive, both to build and maintain. The aristocracy of Paris, St. Petersburg and Vienna competed with each other in creating ever more magnificent glass structures.

Concurrent with the European acquisition of all sorts of new exotics came a surge of interest in the study of botany, meaning that many universities began constructing greenhouses. Leiden, Holland, was the site of what many consider to be the first practical botanical greenhouse. The work of French botanist Jules Charles in 1599, this structure was designed primarily to raise tropical plants for use as a source for medicines. Greenhouses continued to become both larger and more complex throughout the 17th century.

Victorian Golden Age
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The Palm House in England's Kew Gardens
It’s no accident that the golden age of the greenhouse coincided with a repeal of taxes on window glass in the mid 1800s. Glass, previously precious, was now manufactured in large quantity and made widely available. Regent’s Park in London and the Jardin d’Hiver (Winter Garden) in Paris, both constructed in the mid-1800s, allowed genteel visitors an opportunity to mingle as they strolled through controlled environments filled with unusual orchids, palms, ferns and other tropical plants. The Victorians saw the greenhouse as more than just a house for plants -- it allowed industrial city dwellers an opportunity to reconnect with nature. Probably the most iconic representation of the Victorian greenhouse is England's Palm House, a part of Kew Gardens. Constructed between the years 1844 and 1848 under the patronage of Queen Victoria, this huge span of glass and iron was viewed as a technological marvel of the age. Its pioneering pillarless design was based on techniques borrowed from the shipbuilding industry.

Greenhouses in America
Andrew Faneuil, a well-to-do Boston merchant, gets the credit as the builder of the first American greenhouse in 1737. George Washington, wishing to serve his guests pineapple, built a greenhouse especially to grow the fruit at his home in Mt. Vernon. As in England, greenhouses in America became more common and more affordable throughout the 19th century.

The Wye Orangery, built in 1785 on a plantation on Maryland’s eastern shore, is America’s only remaining 18th century greenhouse. The plantation itself is recognized as the place where
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Frederick Douglass
African-American statesman Frederick Douglass spent part of his childhood years in slavery. Recent archeological work within the greenhouse has unearthed a fascinating history never mentioned in Douglass’ writings. Artifacts indicate that not only did slaves maintain the greenhouse and stoke the fires that provided heat for the plants, but that they also lived in quarters within the structure. Archaeologists found objects used in African religious traditions beneath a doorstep. Most intriguingly, evidence suggests that through their decades of toil within the greenhouse, the slaves were also conducting a series of agricultural trials on medicinal and food plants.

Greenhouses Today
Modern small greenhouse structures for ornamental or fruit and vegetable plants are priced reasonably enough for almost any gardener’s budget. You can even build your own greenhouse from a kit. Today, Eurofresh Farms in Willcox, Arizona, claims to be the largest commercial American greenhouse, with over 318 acres of facilities that produce tomatoes and cucumbers. Such hydroponic greenhouse culture of food plants can also help feed people in developing countries with inhospitable climates. No longer just status symbols for the very rich, modern greenhouses can now help meet the nutritional needs of entire nations.
Sources:
"Firsts: Origins of Everday Things That Changed the World" by Wilson Casey, Alpha Books, 2009

Medieval and Renaissance Gardens

Kew Gardens: Palm House

Discovery.com; “Slaves Hid Charms in Colonial Greenhouse”; Emily Sohn; Feb. 2011

Eurofresh Farms

Images:
Greenhouse thumbnail by azmichelle

Palm House at Kew Gardens from Wikimedia Commons

Jardin d'Hiver in Paris from Wikimedia Commons

Frederick Douglass image from Wikimedia Commons