Resource Book on Horticulture Nursery Management

Plastic Film Greenhouse
These greenhouses are covered with flexible plastic films (made up of
polyethylene, polyster or polyvinyl chloride). Plastic covering of greenhouse is popular
because it is cheap and the cost of heating is less as compared to glass greenhouses, but
such films have short life. For example, the best quality ultraviolet (UV) stabilized film
can only last for four years. Quonset design as well as gutter-connected design is
suitable for using this covering material.
Advantages of Plastic Film
The time required to cover a green house structure using this covering material
is minimum. It reduces costs of management and the use of equipment. The savings in
fuel as well as the lower initial purchase price of the plastic film is also advantageous
than glass greenhouse.
Disadvantages of Plastic Film
These covering materials are short-lived compared to glass and FRP. Though
highest quality of plastic is ultraviolet (UV) light-resistant, 6 mm thick polyethylene
films can last only for four years. The UV rays of the sun damage the plastic. It
becomes brittle and darker. It tears very soon.
Rigid Panel Greenhouses
Polyvinyl chloride rigid panels, fiber glass-reinforced plastic, acrylic and
polycarbonate rigid panels are used as the covering material in this type of greenhouses.
These panels can also be used in the Quonset type frames or Ridge and Furrow type
frames. This material is more resistant to breakage. The light intensity is uniform
throughout the greenhouse when compared to glass or plastic. High grade panels have
long life even up to 20 years. The main disadvantage is that these panels tend to collect
dust as well as to harbor algae, which results in darkening of the panels and subsequent
reduction in the light transmission. There is significant danger of fire hazard.
Glass Greenhouses
The average cost per year of a Glass house is more than that of plastic film
greenhouses. Several styles of glass greenhouses are designed to meet specific needs. A
Glass house is preferred when the greenhouse is to be placed against the side of an
existing building. It makes best use of sunlight and minimizes the requirements for roof
supports. An even-span greenhouse is one in which the two roof slopes are of equal pitch
and width. Glass greenhouse is seldom used today because they are not adaptable to
automation. Individual greenhouses standing free of one another are well adapted to cold
climates since snow easily slides from their roofs. A ridge-and-furrow design refers to
two or more green houses frames connected to one another along their length. The side
wall is eliminated between greenhouses, which results in a structure with a single large
interior. Consolidation of interior space reduces labor, lowers the cost of automation,
improves personnel management, and reduces fuel consumption because there is less
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