How to choose a film for a greenhouse?

Every year the number of gardeners, agronomists, and agribusinesses who are abandoning polycarbonate and cheap polyethylene in favor of perennial greenhouse films increases. But how do you choose the proper film for a greenhouse? What to pay attention to when buying? Let's consider in our article.

What is the film made of?

The film market is quite extensive, so it is pretty easy to get confused when choosing a greenhouse film. The first thing to pay attention to is the material from which the film is made. There are many types of material for producing the film: polyethylene, metallocene polyethylene, eva-polymer, etc. Let's look at the most popular materials.

Low Density Polyethylene (LDPE)

This type of polyethylene is the primary type for the production of films. This kind of polyethylene film has a low strength, usually designed for one year of use. LDPE films are the cheapest material for covering greenhouses.

Linear polyethylene (LLDPE)

Linear polyethylene is more high-strength than conventional polyethylene. The cost of such polyethylene film will be higher.

Metallocene linear polyethylene (mLLDPE)

Films made of metallocene polyethylene have excellent mechanical strength and the potential to reduce thickness. This substance is quite expensive, so it is used in professional greenhouse films.

EVA copolymer

A copolymer of ethylene with vinyl acetate. Compared to conventional polyethylene films, EVA-film has more excellent frost resistance, durability, and rubber-like properties. The cost of such films will be higher, but the service life is seven years.

Additives in greenhouse film

In addition to the production material, the various additives introduced by film manufacturers are also essential. Let's look at the main additives for greenhouse film.

UV-stabilizers

This additive is necessary for UV stabilization. If this additive is present in the film, the product will be more resistant to ultraviolet light and not cloud quickly.

Heat retaining additive

The additive affects the temperature inside the greenhouse. If it is present, the microclimate in the greenhouse will be more stable. If there is a sudden drop in temperature due to climate or time of day, the greenhouse will be consistently 2-4 degrees warmer.

EVA

Sometimes manufacturers use EVA copolymer as an additive. In this case, the cost will be lower than the film made entirely of EVA. In this case, the film will cost less and have a rubber-like effect.

AF additive

The antifog additive affects the hydrophilicity property. It attracts water to the film, so condensation does not form inside the greenhouse.

Thermal stabilizer

This additive saves the film from overheating both during production and during operation.

There are many other less common additives. We have looked at the main ones that you should pay attention to when choosing a film.

Film Specifications

The combination of production material and additives affects the characteristics of the film.

-           Service life: from 1 season to 7 years;

-           Durability;

-           Heat retaining effect;

-           Rubbermaid;

-           Wind and hail resistance;

-           Frost resistance;

-           Resistant to cracking and puncturing;

-           Hydrophilicity;

-           Light transmission;

-           Thickness.

Hydrophilicity

An important characteristic is a hydrophilicity. This is the ability of the film to attract water to itself. If special additives for hydrophilicity have been introduced during production, water vapor will condense on the film and turn into a uniform water layer. Water will flow to the edges of the dome and into the soil. The film retains its transparency and ability to transmit sunlight.

Color and translucency of greenhouse film

To get the material in different shades, a food coloring is usually added, which tends to burn out in the sun, so there is no point in it. If the dye is persistent, less light will enter the greenhouse, leading to lower yields and the need for additional lighting.

For the plants in the greenhouse, it is the light transmittance that is important. The light transmission coefficient in the area of physiologically active radiation (PAR) is how much of the solar radiation required for photosynthesis reaches the plants through the film. For example, SVETLITSA™ film has a transmittance factor of up to 92%.

Thickness of film for greenhouses

Thicknesses range from 100 to 200 micrometers or microns. The choice of thickness depends on the region of location, size of the greenhouse, and others. Based on customer feedback, we have made general recommendations for film thickness.

How to choose a film for a greenhouse?

To summarize: when choosing a greenhouse film, pay attention to:

1)      Material from which the film is made;

2)      Additives;

3)      Film Specifications;

4)      Film thickness.

Read more about SPF " Shar" greenhouse films here.