Wednesday, 2 October 2013

Classification of Greenhouses

Classification of Greenhouses

Greenhouse structure  of various types are used for crop production. Although there are advantages in each type for a particular application, in general there is no single type greenhouse, which can be constituted as the best. Different types of greenhouses are designed to meet the specific needs. 

The different types of greenhouses based on shape, utility, material and construction are briefly given below: 

1.  Greenhouse type based on shape:

For the purpose of classification, the uniqueness of cross section of the greenhouses can be considered as a factor. The commonly followed types of greenhouses based on shape are:

  • Lean to type greenhouse.
  • Even span type greenhouse.
  • Uneven span type greenhouse.
  • Ridge and furrow type.
  • Saw tooth type.
  • Quonset greenhouse.
  • Interlocking ridges and furrow type Quonset greenhouse.
  • Ground to ground greenhouse.

2.  Greenhouse type based on Utility

Classification can be made depending on the functions or utilities. 
Of the different utilities, artificial cooling and heating are more expensive 
and elaborate. Hence based on this, they are classified in to two types.
a)  Greenhouses for active heating.
b)  Greenhouses for active cooling.

3.  Greenhouse type based on construction

The type of construction predominantly is influenced by structural material, though the covering material also influence the type. Higher the span, stronger should be the material and more structural members are used to make sturdy tissues. For smaller spans, simple designs like 
hoops can be followed. So based on construction, greenhouses can be classified as 
  • Wooden framed structure.
  • Pipe framed structure.
  • Truss framed structure. 

4.  Greenhouse type based on covering material

Covering materials are the important component of the greenhouse structure. They have direct influence on greenhouse effect, inside the structure and they alter the air temperature inside. The types of frames and method of fixing also varies with covering material. Hence based on 
the type of covering material they may be classified as

  • Glass glazing.
  • Fibre glass reinforced plastic (FRP) glazing
    • i.  Plain sheet
    • ii.  Corrugated sheet.
  • Plastic film
    • i.  UV stabilized LDPE film.
    • ii.  Silpaulin type sheet.
    • iii.  Net house.
  • Based on the cost of construction involved ( which includes various factors mentioned from above)
    • i  High cost Green House
    • ii  Medium cost Green House
    • iii  Low cost Green House
The structural requirements and the cost per unit area for different models of low cost green houses for cultivation of vegetables are detailed below with diagrams to enable an interested entrepreneur to construct a low cost green house on his own accord. 

However, the local weather conditions and the individuals necessity play a major role in the selection of the model.  

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