Why We Have Greenhouses

Think of the greenhouse and you tend to think of a small glass structure in a back garden or on an allotment. However, the greenhouse concept isn’t just about growing a few flowers as a pastime. They are used in more serious ways as well.
From a small cold frame to a giant industrial polytunnel, the principle behind all greenhouses is the same. They create a warmer, controlled environment which aids the growth of plants. Whether the walls are glass or plastic, they will be transparent which allows light and warmth to enter. However, because the structure is solid, the warm air cannot escape, meaning the temperature can rise considerably compared to that outside. In some cases, people will also use heaters to keep frost at bay overnight.

Higher temperatures are not the only benefits, however. While this does encourage growth and can protect plants from frost, there is also the fact that you can easily control other aspects of the environment, such as water. Outside, when it rains, there is little you can do about it. In a greenhouse, the room keeps the environment dry. This is great if you’re trying to grow plants from warm, dry climates. You can simply water them as necessary without worrying about their drowning.
We all know how greenhouses are used domestically, but larger ones are put to use producing food in great volume. For example, in Spain, there is a 50,000 acre greenhouse complex producing all manner of foodstuffs.
As well as growing plants better suited to warmer climates, greenhouses also allow us to grow native plants during more of the year. Increased temperatures in spring and autumn mean that you can start growing earlier and continue harvesting later.
The Netherlands is another country where greenhouses are used extensively. It is estimated that as much as 0.25 per cent of the nation’s surface is covered in greenhouses which are devoted to growing flowers, fruit and vegetables.
Another famous greenhouse is the Eden Project in Cornwall. These giant biomes feature large numbers of plants from abroad. Different biomes have different climates, meaning Mediterranean and tropical plants are all on display. It has become a hugely popular tourist attraction and people come from far and wide to see banana trees and coffee plants growing in the UK.
Without greenhouses, we would have far more limitations on our diets. Growing under glass allows for a wider range of plants to be grown during a larger proportion of the year and that is of benefit to everyone.
Malcolm Poole has a greenhouse and is writing on behalf of www.greenhousepeople.co.uk