Greenhouse Coverings

The most important function of a greenhouse covering is to allow the maximum amount of light into the greenhouse for the growth and development of plants.

1. Glass

   The main advantage of glass is that it provides the best light transmission of any greenhouse covering. However there are some disadvantages:

   • Cost of glass is very high
     
     
   • Cost of heating the greenhouse is higher
     
     
   • Problems with vandalism
     
     
2. Polyethylene

   Advantages are:

   • The initial cost is cheaper
     
     
   • Fuel costs are lower
     
     

   Disadvantages are:

   • Polyethylene has a short life span; UV light causes breakdown of polyethylene. When UV inhibitors are applied to polyethylene the average life is three years.
     
     
   • Condensation on the inside surface of the greenhouse can lead to disease occurrence and a reduction in the amount of sunlight entering the greenhouse.
     
     
3. Fiberglass-Reinforced Plastic

   The biggest advantage of fiberglass-reinforced plastic is that it allows the same amount of sunlight through as glass. However, in recent years fiberglass-reinforced plastic has decreased in popularity because of the following disadvantages:

   • Very susceptible to UV light, dust and pollution degradation.
     
     
   • Flammable and thus insurance rates may be higher.
     
     
4. Acrylic and polycarbonate

   Acrylic and polycarbonate types of greenhouse coverings have almost completely replaced the use of fiberglass-reinforced plastic because of the following advantages:

   • Lightweight and easy to install
     
     
   • Excellent heat insulating ability
     
     
   • Good light transmission
     
     

   A disadvantage is that it is flammable.