F. Tognoni, G. Serra
The history of protected cultivations has been marked by three dramatic events, affecting their quantitative and qualitative development:
  • the industrial production of flat glass
  • the advent of plastic
  • the energy crisis

In spite of the fact that the first glass beads found in Babylonia may be dated back to 2,600 BC, for a few millennia glass was employed exclusively for decorative, optical and artistic purposes. Until the late 18th century, glass was a rarity in the homes of ordinary people, apart from a few small windows. By the end of the 19th century glass was a common material thanks to new industrial processes that allowed glassmakers and engineers to astonish the world with the Crystal Palace in London made from 300,000 sheets of glass resting on a lightweight iron framework. In the 17th century greenhouses were ordinary brick or timber shelters with a normal proportion of windows and heated in some way or other. As the need for light was realized and glass became cheaper and available in sheets the greenhouse gradually evolved, with more sophisticated forms of heating, into glasshouses roofed and walled with glass with a minimum of wooden or metal skeleton. By the mid-19th century, protection was transformed from being a mere refuge from a hostile climate into a controlled environment.

The era of plastic started in 1862 when Alexander Parkes invented Parkesine or Xylonite, followed by many other and more sophisticated compounds, but it was not till 1939 that polyethylene was synthetized. Such a compound was originally used for radars, and after the 2nd World War it had a wider application in the agricultural field. Many other materials rapidly sprang from polymerization. The coming of industrial flat glass transformed greenhouses into glasshouses, and plastics, in their turn, transformed the latter into plastic houses. As from 1960 the tremendous increase of the surface covered with plastics relegated glass covered areas to a little more than one tenth of the whole of protected crops. At the same time there was a similar inversion of the ratio between flower and vegetable crops: plastic reduced investment costs making it advantageous to protected vegetables too.

The third revolutionary event was on outcome of the war between Israel and the Arab States in the fall of 1973, when OPAEC (the Organization of Arab Petroleum Exporting Countries) put an embargo upon oil shipments to certain countries. The success of this

Tognoni, F. and Serra, G. (1988). BIOLOGICAL ASPECTS OF ENERGY SAVING IN PROTECTED CULTIVATION. Acta Hortic. 229, 17-20
DOI: 10.17660/ActaHortic.1988.229.1

Acta Horticulturae