6 Types of Greenhouse Poly Film Coverings
Every grower strives to produce the best crop they can while keeping production costs to a minimum. The covering overhead is a major component, and when extras are added – anti-condensate, thermal capabilities, or bee compatibility – grower costs start to rise.
The product you choose has to fit your crop, polyethylene films offer the plants inside your greenhouse structure extended protection against harmful outdoor elements including wind, rain, snow, and persistent UV rays. Polyethylene film is a simple and cost-efficient solution to give your greenhouse the covering it needs. Below are some examples of films and what they each offer.
But light distribution, achieved through control of light diffusion, is often overlooked when discussing light quality for plants. Light quality should not only be thought of as light spectrum but also should include light diffusion.
From sunlight to supplemental lighting, let’s take a look at light diffusion and which greenhouse film is best suited for your unique cultivation requirements.
What is Light Diffusion?
Simply put, light diffusion is the scattering of light. It is photons bouncing around in all directions. In its most simple form, think about standing under a large outdoor shelter when the sun is highest in the sky. If there was no diffusion of light at all, it would be very bright outside the shelter but totally dark under the shade of it. The reason we can still see well in the shade is the natural diffusion of sunlight by our atmosphere.
Light quality is crucial in horticulture because it inhibits photosynthesis at all levels of the plant. Optimizing light quality is one of the ways you can control the plant photosynthesis process, and greenhouse film coverings are one of the tools to help accomplish this.
Types of Greenhouse Film
Depending on your crop or climate conditions most growers choose a double poly system with a blower in between to keep the layers inflated which will provide an insulation layer for the crop. Either a clear or white film offers you the best protection to suit your growing needs, especially if you are growing in an environment that needs more sunlight. Clear or white greenhouse film can also be effective at light deprivation to reduce heat and reflect UV rays.
IRAC- Infrared with Anti-Condensate Control
IRAC Films bring the radiation from the sun into your greenhouse to help with heating while the anti-condensate control will keep the film from dripping in the greenhouse when the temperature is cool outside but warm and humid inside on the crop. This type of greenhouse film is used in many application settings and is optimal for different seasonal climates.
IR/AC film is also a good choice for the inside layer of a double wall poly greenhouse because of the features and benefits like excellent light transmission, up to 20 percent energy savings due to heat control, provides up to 60 percent diffusion, and offers condensation control.
Diffusion/ Cooling Films
Multiple companies offer a highly diffused greenhouse film that improves growing conditions by using controlled diffusion to influence the light reaching the plant. It is designed to make more light available to plants by increasing the amount of diffused light. The reduction of short-wave infra-red radiation enhances the useful light within the PAR light spectrum. The diffusion of light spectrum from the sun makes these photons reach deeper into the plant canopy. This four-year, 6 mil film is the ideal choice as an outside layer, and the perfect partner when combined with an IRAC film as the interior layer of a double-wall poly greenhouse. This leads to healthy, bushy plants while reducing greenhouse temperatures.
Woven Poly Film
These films can be used as a single layer or in a double-wall poly system and feature UV stabilization. Woven films have amazing puncture and tear resistance to hold up in tough environments. Woven poly films come in IR, and Anti-Drip can have excellent UV block and enhanced light diffusion.
This type of greenhouse film is also effective to cover expensive equipment, dirt, and temporary enclosures. While this film can be a viable option for many greenhouse growers, it does lack crop-boosting properties that help increase harvest yields.
UV Open Films
This product has undergone IR treatment, which helps it preserve more of the sun’s infrared radiation and disperse it at night. It features a clear, open design, allowing it to transmit about 90% of natural light from the 300 to 400 nm spectrum. It’s also a durable polyethylene material. The wonders of this polyethylene film cover don’t end there. Its light diffusion rate stands at a noteworthy 75%. The more it diffuses light, the less apparent shadows become, allowing heat and light to cover the entire growing space more consistently and deeper into the plant canopy. These films can have anti-condensate properties added too, meaning they will prevent fog and droplets from forming in their inner layer.
Luminescent Greenhouse Film
What is luminescent film? Quantum dots in greenhouse covering materials convert a portion of the sun’s UV and blue light into more potent orange and red light. Orange and red light is more efficiently converted into plant energy by chlorophyll versus green, blue, or UV, which increases light quality and optimizes photosynthesis.
The UbiGro greenhouse film optimizes your sunlight with red-shifting quantum dots that are efficient in manipulating colors of light. Crops take advantage of enhanced photosynthetic efficiency from a red-shifted spectrum to produce more energy that plants use for fruit and flower production. This ultimately leads to improved crop yields and additional revenue in your greenhouse.
These are just some of the popular examples of the many coverings available to growers. As always you should consult your greenhouse manufacturer or whomever you are buying your greenhouse supplies from to find just the right fit for your growing conditions and crops!