Greenhouses of Hope

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Who has not heard the phrase "these are greenhouse-grown vegetables"? Certainly, most of us know what greenhouses are; they allow us to grow vegetables and fruits out of their season. Greenhouses are by no means a new invention, as they have been used by farmers since the 17th century; but, how have greenhouses developed over the years? What are their advantages and disadvantages?

Greenhouses are enclosed spaces that provide a warm climate for some plants that are affected by temperature; they protect these plants from excess heat or cold. The structure of greenhouses has evolved over time; the first greenhouses were made of bricks or wood with traditional means of heating. Then, in the 19th century, they developed and were made of glass, with more advanced means of heating. Nowadays, greenhouses are made of glass or plastic, with an integrated system to monitor the temperature and light, the amount of water in the soil, in addition to the stages of plant growth inside the greenhouse.

Greenhouses are widely used to grow seasonal crops; using certain techniques, crops can be produced all year round, especially crops that are highly consumed for food. They are not only used to grow essential crops, but they are also used to grow ornamental plants and rare flowers, which makes them economically important.

A Dutch greenhouse from the 1930s, built against a brick wall. Picture: Naaldwijk in oude ansichten. Source.

The Technique

The main idea of greenhouses is to maintain heat and redistribute it inside the greenhouse so that it does not change at high rates; moreover, this heat helps the plants grow faster. When warm sunlight enters a greenhouse through its surface, whether it is made of glass or plastic, the greenhouse maintains the heat and does not disperse it easily, even if the weather is cold. Industrial thermal generators can also be used inside the greenhouse without relying entirely on sunlight.

The Advantages

Greenhouses have many advantages, the most important of which are:

  • The economic benefit mentioned earlier, which is to grow consumable crops out of their season, such as cucumber, tomatoes, zucchini, oranges, etc.
  • Saving irrigation water, and using the dripping irrigation system, because greenhouses help maintain water in the soil to a large extent.
  • Protecting plants from insects and agricultural pests, which may cause damage; thus, reducing the use of pesticides in growing the plants.
  • Raising agricultural productivity, where the same area of soil can produce more crops if we use greenhouses.
  • The possibility of cultivation in relatively poor soils.
  • The need for a smaller labor force.

The Disadvantages

Despite the advantages presented earlier, greenhouses have some defects and problems, including:

  • High cost: even though the cost of glass and plastic is relatively low, the generators, thermostats, in addition to other machines and equipment are expensive.
  • Some of the machines and generators used in greenhouses run using fossil fuels; thus, contributing to environmental pollution.
  • Any minor deficiency in the design, structure, or operation of the greenhouse may affect the production negatively; hence, putting the crops at high risk.
  • Even though it is rare to find agricultural diseases or pests within the greenhouses, the loss can be significant if any of them appears, because the heat inside the greenhouse will help the disease spread ten times faster than normal.
  • Although greenhouses do not need a large number of workers, these workers must be highly trained, competent, and skilled; therefore, they are highly paid, which may increase the overall cost.

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Greenhouses are an economic endeavor in the first place; they can provide numerous crops if implemented correctly, but there are challenges that owners may face to obtain the required production.

References

britannica.com
grtrailers.com
home.howstuffworks.com
sciencing.com

Images: freepik.com

The original article was published in the SCIplanet Magazine, Autumn 2020 issue.

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