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Plastic Greenhouse Films
By Paul Wonning

Greenhouse plastic films are specially manufactured plastics designed to withstand the penetrating ultraviolet (UV) rays of the sun, as well as wind and frigid winter temperatures.

The most common greenhouse plastic is six millimeter four year film.
This plastic is fairly heavy, at six millimeters thick, and it should last for at least four years. Sometimes it will last a bit longer.
It commonly is available in rolls of varying lengths and widths. The better grades will have light transmissions capable of producing excellent plant growth.

Another type of plastic film you may find is what is called “over wintering” film.
This greenhouse covering is suitable for only one season’s growth.
Typically, commercial growers use it on greenhouses in which they are storing balled and burlaped or containerized nursery stock over the winter.
The homeowner desiring this type of use for a single season may find builders grade clear plastic at a hardware store useful.
Since it is locally available, it may be cheaper and quicker to get.
But this stuff will only last a single season, so don’t use it on a permanent house, unless you want to change the plastic every year.
Care must be taken to make sure it is changed, because this stuff can break down rather abruptly.
Nothing can be so disheartening as to the grower who tries to stretch an extra season out of this plastic, only to have it blow away during a January snowstorm, exposing the plants within to a cold winter blast.


Photo / pic / image of Polytunnels.
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Plastic films are secured to wooden structural elements of the greenhouse using vinyl batten tape stapled down with three eighth inch staples.
Metal strips such as those used to mount shelving on walls in the home may be used by the homeowner on a small greenhouse.
It can be screwed down using drywall screws and a battery powered screw shooter.
These metal strips are reusable, as are the screws and do an excellent job of holding the plastic securely.

It can pay dividends to keep some good quality clear packing tape on hand to mend tears in the plastic.
There is a specially made tape for this purpose which commercial growers use, but is a bit expensive.
A GOOD quality packing tape is sufficient for the home greenhouse owner.

If your greenhouse is to be heated year round, it can pay dividends to use a double layer of plastic to cover the greenhouse.
A special blower available from greenhouse supplier blows air in between the plastic layers, creating an air pocket between the layers.
This is excellent insulation and can cut greenhouse heating costs significantly. It does cut down on light transmission, but not enough to create a problem for your plants.
Most commercial growers use this type of covering system.

Plastic covered greenhouses are an economical choice for the home gardener.
The ideal plastic used should be a good greenhouse grade which lasts a few years and provides good light transmission.

© 2006 Paul Wonning is the owner of http://www.gardensandnature.com/ a web site about gardening, hiking and other nature related topics.
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