All About Greenhouse Plastics

Greenhouse plastic covering

Much like you, your greenhouse would have a very hard time functioning without its skin. It’s one of those things you don’t pay much attention to once it’s on, but when it’s missing or starts to malfunction, the problems multiply big time. Many greenhouses are skinned in greenhouse plastics, and although they’re a great choice for covering a wide range of structures, there’s a difference between the types of greenhouse plastics—it’s not a one size fits all sort of situation. Let me walk you through the most common options.

Polyethylene film

The most inexpensive option for greenhouse operators on a budget. This material comes on rolls or folded in a flat package and is designed to be taped, stapled or attached to your greenhouse frame with clamps. Although polyethylene film made for greenhouses is generally impregnated with an ultraviolet inhibitor to extend its life, you can expect to replace basic polyethylene once a year. This material cannot be recycled, it’s really best if used as a temporary measure if at all.

Reinforced polyethylene film

This film gets its durability from the bonding of three layers of low density polyethylene. The two outer layers are standard clear film, while the inner layer is woven in a loose grid pattern. The whole thing is sandwiched together and heated to create a laminated product that is significantly stronger than the base parts.

Reinforced polyethylene film is puncture and tear resistant, and resists cracking from the cold. It has a functional life of about three years, but allows less light penetration than a single layer of polyethylene film. Delamination can be a problem, but this material is otherwise a good greenhouse skinning material.

Woven polyethylene

This plastic has been woven from multiple layers of polyethylene strips to create a tough, durable material that can be used to skin a greenhouse or cold frame. Unlike basic polyethylene, woven polyethylene resists tears and punctures, making it a much better option if winds are a problem.

You can expect to get three to four years of use out of a woven polyethylene product under bright sun conditions, and up to ten if your greenhouse is well ventilated and placed in a more protected spot. Because of the weave on this material, light scatters readily when it passes through, up to 15 percent of the light that enters may be lost when compared to glass.

Corrugated polycarbonate

This thin, durable material is molded into an undulating pattern to create channels that move water away from structures. It’s frequently used to roof porches, but makes a suitable greenhouse material as well. Corrugated polycarbonate can be purchased in a variety of colors and opacities, but the clearest options are similar to glass in their light transmission abilities.

While not easily broken, corrugated polycarbonate can shatter quite explosively if mishandled, so always remember to mow away from your building to avoid throwing rocks through it. You’ll need special fasteners to install corrugated polycarbonate, but it’ll last you at least 10 years even with major abuse.

Double-walled polycarbonate

This covering has excellent insulation properties due to the unique way in which the polycarbonate sheets are bonded. Resembling cardboard, two heavy sheets of polycarbonate are separated by a series of cells that, when installed properly, function as an air pocket and reduce the rate of temperature fluctuation inside your greenhouse. This is the most expensive option for skinning a greenhouse, but it’s also the very best. If your greenhouse is looking forward to a long, productive life and you don’t want to have to fiddle with replacing the skin every so often or crank the heater too much, double-walled polycarbonate is the way to go. These panels do require special hardware to install and can be costly upfront, but will pay for themselves over a lifetime.

Deciding between glass or plastic coverings for your greenhouse? Read Glass greenhouse vs. plastic greenhouse—pros and cons>>

[ background=”#0e2d08″ color=”#a68914″]Kristi Waterworth[/]
image: Jan Tik via Compfight cc
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