Greenhouse basics

A greenhouse is a generic term referring to the use of a transparent or partially transparent material supported by a structure to enclose an area for propagating or growing plants.

Specifically, where the covering material is glass, the structure may be referred to as a 'glasshouse'. A 'greenhouse' or 'polyhouse' refers to the use of plastic films or sheeting. When the enclosing material is woven or otherwise constructed to allow sunlight, moisture and air to pass through the gaps, the structure is known as a 'shade house' or 'screen house'.

When looking to develop or expand a greenhouse enterprise, it is important to make sure that the structures you invest in are suitable and meet your needs.

The shape and design of the structure influences:

  • the amount of light transmitted
  • the amount of natural ventilation
  • the useable internal space
  • efficient use of structural materials
  • condensation run-off
  • heating requirements
  • the cost.

When deciding on a greenhouse design for commercial production, key factors of the greenhouse need to be considered. It is not possible to provide a definitive priority list to suit everyone, but generally, the height of the structure is critical and will have significant bearing on managing the growing environment in a range of conditions. Ventilation is also at the top of the list and roof ventilation is superior to side wall ventilation. Active ventilation systems can also be considered.

Heating is essential for controlled environment horticulture and naturally the computer control systems are critical. Covering materials, screens (thermal and insect) and evaporative cooling systems should also be carefully assessed.