As soon as you acquire a greenhouse, a new and exciting world of gardening becomes possible. Greenhouse gardening has many advantages as outdoors, plants are subject to many hazards, and extremes of weather alone can bring much disappointment. with greenhouse gardening you can have almost full control of the environment. You can govern temperature to a considerable extent and provide artificial warmth if necessary. You can decide how much water the plants should receive, and there is better control of feeding, since nutrients are not washed away by rain as in the open.
The composition of feeds, fertilisers, and nutrients can be balanced better to suit any individual plant types. Weeds, pests, and diseases are easier to avoid and control, and you can take full advantage of sterilised potting composts which make growing so much more reliable. Even light can be adjusted by the use of shading so that plants can benefit from maximum light when it is in need, and shade to any degree you think desirable when the sunlight might be too intense.
A greenhouse can be enjoyed the year round and the winter can be as colourful and interesting as the summer. It is a delightful place in which to work or potter in winter, and it will be greatly appreciated by the retired, the not-so-young, or the infirm. You can use a greenhouse as a place of beauty, and as a conservatory for the display of decorative plants, to entrap their scent and protect them from weather damage; or you can indulge in more down to earth and utilitarian practices fruits and vegetables, cut flowers for sale or floral arrangement or decorating the home, winter salads, flower show exhibits, propagation of garden plants, raising bedding plants, and housing special collections of specialist plants like chrysanthemums, orchids, carnations, alpines, and the like. With a little Warmth, plants from almost the world over can be grown and your scope is unlimited. Greenhouse gardening can be a never-ending adventure.
Nowadays many people like to make the greenhouse part of the home. There is nothing new in this. The Victorians used to delight in very grand conservatories, elaborately built and filled with exotic plants. There they would entertain friends or take afternoon tea. Today there is the modern, more modest equivalent in the form of garden rooms or lean-to structures that can be set against the dwelling. The so-called prefabricated ho1ne extensions are also usually well supplied with large windows and perhaps a roof letting in some light. These, too, make useful garden rooms where many house plants will thrive. .
Only flat dwellers can be ruled out as possible candidates for greenhouse gardening proper, although they can still use windows and have miniature windowsill greenhouses and plant cases. Small greenhouses are now available to suit the smallest garden. You don’t have to have a garden a greenhouse can be erected in a concrete yard or even on a flat roof or large balcony.
HOW THE GREENHOUSE WORKS
The Romans built greenhouses or plant houses of a kind, but the structure as we know it in modern times only became possible with the discovery of glass and the manufacture of glass sheet.
The first building that could be truly described as a greenhouse was erected in the Apothecaries Garden, in Swan Walk, Chelsea, London. This garden, founded in the seventeenth century, still exists today. The greenhouse was therefore a British invention.
The greenhouse eventually became the hobby of the wealthy and in the Victorian era everyone of any distinction had a handsome conservatory or hot house. With the passing of the Victorians greenhouse gardening declined and still remained only possible for the more affluent classes. Since the end of the Second World War, there has been a dramatic change. More people have gardens of their own, more spare time, and longer holidays. At last people are seeing the wisdom of guarding against the freakish pranks of our climate. There have also been advances in greenhouse design. It is no longer necessary to have one built, or to build your own. The market abounds with prefabricated designs to suit all purposes and situations.
Mass production and bulk buying of materials have made possible price ranges to suit all pockets, and more recently plastic has had a further effect in reducing cost. However, at this stage we must learn a little about how the greenhouse functions, since glass and plastic have different properties.
At one time glass structures were known as sun traps. This was owing to the fact that they seemed to catch and intensify the suns warmth in some way and hold it for long periods.
This is because sunshine contains rays that we cannot see or appreciate directly, for example those that give us a sun tan.
When some of these rays (not all) strike an object they may be transformed into heat energy and be radiated away again as warmth, or the object may be heated and warm the air around it.
These short-wave rays (of the type easily convertible to heat) can penetrate glass easily; but the longer waves they are converted into cannot escape back through the glass so readilyhence the warmth-trapping effect. Most plastics are more transparent to the long waves and radiant heat. Consequently a plastic greenhouse may change its temperature quickly with the coming and going of sunshine. Even on sunless days, a certain amount of radiant energy from the sun is getting through the clouds and this is often sufficient to be trapped and keep a glasshouse comfortably warm. In winter when the air is bitterly cold outside, a glass greenhouse interior may be at summer temperature if the sun is shining.