What gardener doesn’t dream of owning his or her own greenhouse? I have had mine for over 25 years. It’s actually a solarium that I fill with plants in the winter and which becomes our dining room in the summer when most of plants are outdoors. Honestly, I can’t imagine living without it!
But greenhouses are nothing new: we can even trace their history back to Roman times.
The first attempts to grow plants under cover probably date back to ancient Egypt, but not much is known about how this was done. By Roman times, however, there are writings that clearly explain their operation.
The first notes about greenhouses can be traced to the reign of Tiberius, Roman emperor from 14 to 37 CE. It seems he wanted to eat fresh cucumbers all the year long, but that wasn’t possible in Rome, where winter temperature are cold and can even drop below freezing.
His gardeners first tried to install cucumber plants on carts so they could drag them into sheds when it became too cold. But if the cold lasted more than a few days, the cucumbers would start to die from lack of light. But someone came up with the idea of covering the structures not with slate, but sheets of selenite, a transparent rock, to let the sun in. These are the first greenhouses for which we have any clear record.
Starting in the 13th century, new techniques made it easier to make panels of glass and by the Renaissance, from the 14th to the 17th century, larger and larger structures with glass windows were being made.
This was a great period of exploration and plants were being brought back from exotic locations: Africa, the Middle East, Asia and, even later, the New World. These tender plants summered outdoors, but would be brought indoors into large greenhouses called orangeries. They got their name because even large fruit trees – orange trees, lemon trees, date palms, etc. – could be overwintered there.
Thus were the first botanical gardens born, first in Italy and then throughout Europe. Originally they were linked to the faculty of medicine of a university, for botany was at the time considered an integral part of medicine.
In southern Europe, a roof or a wall of windows was enough to keep plants warm over the winter, because of the greenhouse effect. The sun warms the interior during the day and enough heat is held captive by the glass to keep the orangery warm throughout the night, even in winter. Further north, however, passive heating simply wasn’t sufficient. Special heating systems were therefore developed to keep the orangeries toastier.
At Versailles, the huge 150 m (492 ft) long orangery, built between 1684 and 1686, was designed to contain 1000 orange trees and other subtropical fruits grown in large crates when they were moved indoors over the winter. It was heated by coal furnaces. The heating system was so inefficient that some plants froze, others baked, most were quickly covered in soot and many would be half dead by spring.
Of course, orangeries don’t quite fit our modern image of a greenhouse, as they have a solid roof and walls. Only the large doors through which the plants were brought indoors in the fall and out again in the spring were glazed. The orangery of Versailles wasn’t actually developed with much thought about letting the sun in: it is located under a terrace and doesn’t even face south, but rather northwest! So much for taking advantage of the greenhouse effect!
The Modern Greenhouse is Born
In the nineteenth century, European countries abolished taxes on glass windows and they suddenly became much more popular. Houses started to have more and much larger windows and the first modern greenhouses, fully glazed, appeared. And greenhouses were also no longer the sole preserve of botanical institutions: it became very fashionable to add a small greenhouse to any major house. Such a structure would be called a winter garden or conservatory.
In the winter gardens of large estates, it became fashionable to grow exotic plants: ferns, orchids, palms and others, something to impress visitors.
The same estate would have also have had one or more glasshouses (horticultural greenhouses), also called hothouses, separate from the house itself, for the cultivation of vegetables, flowers, and fruits, as it was considered appropriate at the time for every rich landowner to produce his own oranges, bananas and pineapples for the table of his guests, not to mention cut flowers to decorate vases all winter.
The famous greenhouses at Longwood Gardens (Pennsylvania) began their life as simple hothouses for nectarines, figs, grapes, and cut flowers… before expanding into something much, much more. And the home itself, the Peirce-Dupont house, has a very large conservatory built right into it. Visit just about any historic estate and there will be long rows of glasshouses out near the vegetable garden… or at least, the traces of the foundations will still be there, as sadly many of them are no longer being maintained.
The nineteenth century was also the era of grand public greenhouses, such as the Jardin d’hiver on the Champs-Elysées in Paris (1846) and Crystal Palace in London (1851), both of which served not only to wow people with new exotic plants, but were also the convention centers of their time. These two enormous greenhouses no longer exist, but many European, North American and Australian cities still have one or even several large Victorian-era public greenhouses: Paris, London, Dublin, St. Petersburg, New York, San Francisco, Toronto, Montreal, Adelaide, etc.
If you just can’t stand winter anymore and a trip to Cancun is not in your budget, why not escape to a public greenhouse for an hour or two? Their tropical heat, humid atmosphere, deliciously earthy scents and abundance of plants of all shapes and colors is guaranteed to perk you up. If there is no public greenhouse in your city, try a local garden center: there is bound to be one that is open year round and they cost nothing to visit.
Personally, I use my own greenhouse for therapeutic purposes. Whenever I feel down or a bit off, I slip off to the greenhouse and muddle about for a few minutes, then, my batteries recharged, off I go, back to work. This is almost an automatism. I sometimes find myself in the greenhouse without even remembering having gotten up from my desk: it’s as if my body knew it needed a break and just took over!
Who knows? Perhaps there will be a beautiful “winter garden” in your future too! Keep your fingers crossed!