Since
the construction of the first greenhouses a few centuries ago, they are widely used to accelerate the growth rate of plants, as well as
to optimize the quality of crops and increase the quantity of their production.
The kind of crop and its demands, the climate change in a particular location and the growing season are the most important criteria to have in mind in order to construct a greenhouse. For these reasons, a greenhouse varies according to its type, its dimensions, its equipment, and even its coating materials. As for the shape of a greenhouse it can be of arched shape, gothic or ambiguous. The current trend related with greenhouse height is using increasingly uprights up to 7 m in order to ensure an ideal setting for crops.
The framework of a greenhouse can be made of wood, steel, or aluminum, while the coating materials of its surfaces vary in their nature and their properties. The most common are GRP sheets, polycarbonate sheets, polyethylene film and glass. The costs of building greenhouses depend mainly on the technology used and their construction materials as shown below:
• Low technology greenhouses which have a cost between $15,000-$40,000 per 1,000 sq.m.
• High technology greenhouses with long-lasting manufacturing materials and automatic equipment that cost between $40,000-$60,000 per 1,000 sq.m.
A greenhouse must be in a
position to take full advantage of the sun, provide water for watering and if
it is necessary to use windbreaks to protect itself from strong winds. A separate small warehouse
can be used as an auxiliary facility to store tools and supplies, to provide a
working space and perhaps to house the
heating system of the greenhouse. A key point of paramount importance for a
greenhouse is also its ventilation, so there are ventilation windows on the
roof or the sides of it to ensure minimal ventilation and recycling of the total
volume of the air inside it.
Larger greenhouses are more efficient and more economical than small ones, because they cost less per sq.m. and the surrounding space that hosts them can be kept more homogeneous. Heating and ventilation systems are the most expensive greenhouse equipment, and their cost per unit area is smaller in large greenhouses.