To choose greenhouse film, match five things to your crop and site: thickness (measured in microns), light diffusion, UV properties, functional additives such as anti-drip, and a roll width that covers your structure with enough left over for fixing. For commercial tunnels in Australia, 180 to 200 micron films are common, and diffused films are widely used for crops that benefit from even light.
Greenhouse and tunnel film (often called greenhouse plastic or poly) is the skin of your structure. It controls how much light reaches the crop, how evenly it is spread, how the structure handles condensation, and how often you need to re-skin. Here is what each specification means and how to compare films.
What does film thickness (microns) mean?
Film thickness is measured in microns (µm or “um”). One micron is a thousandth of a millimetre, so a 200 micron film is 0.2 mm thick. Within the same film type, thicker film is generally stronger, more resistant to tearing and puncture, and heavier to handle. Thickness alone doesn’t set how long a film lasts outdoors. That depends mainly on its UV stabilisation and on how well it is installed.
180 micron vs 200 micron
- 180 micron is widely used for berry tunnels and seasonal or lighter structures where film is handled often.
- 200 micron gives extra strength for permanent greenhouses and exposed, windy sites.
Oz Bunji supplies 180-micron berry film rolls (including 11.2m wide commercial rolls) and Aster+FILM 200um greenhouse film.
Clear or diffused film?
Clear film lets light straight through, producing sharp shadows and bright spots. Diffused film scatters the light as it passes through, so it reaches deeper into the canopy and lower leaves, with fewer hot spots and less risk of fruit and leaf scorch. The diffusion level is usually stated as a percentage (for example “55% DIF”). Diffused films are popular for berries, vegetables and other crops grown under Australia’s high summer light.
What do UV stabilised, UV-open and UV-blocking mean?
- UV stabilised means additives protect the plastic itself from breaking down in sunlight. This is the main factor in how many seasons a film lasts. Check the manufacturer’s rating for your region.
- UV-open films let a share of ultraviolet light through to the crop, which growers use where pollinator activity or fruit colour matters.
- UV-blocking films filter UV out and are used in some situations to influence certain pests and diseases.
Functional additives: anti-drip and anti-dust
- Anti-drip (anti-condensation): makes condensation run down the film as a sheet instead of forming droplets that fall on the crop. This reduces wet foliage and fruit, which helps with disease management, and keeps light transmission higher.
- Anti-dust: reduces dust building up on the outside of the film, helping it keep its light transmission between cleans.
- Thermal / IR additives: some films are designed to hold more heat overnight. Ask your supplier if this matters for your climate.
How wide and long should the roll be?
Measure the full arch over the hoop from ground fixing (or side rail) on one side to the other, and add an allowance for your fixing method, whether that’s channel and wiggle wire, burial, or roll-up sides. Then choose the roll width that covers that measurement in one piece. Roll length should cover the tunnel length plus the ends you need to wrap or fix. A single wide piece is stronger and seals better than joined strips, which is why commercial tunnels often use wide rolls such as 11.2m or 12m.
Installation tips that extend film life
- Install on a calm, mild day so the film can be tensioned evenly.
- Keep the film tight. Flapping causes most premature wear and tears.
- Pad or tape any sharp edges and hot metal where the film touches the frame.
- Use a proper fixing system: channel and wire, tunnel rope, or clips.
- Have a repair kit ready so small tears are fixed before they spread. See how to install and repair greenhouse film.
Film, shadecloth or both?
Film keeps rain and cold out. Shadecloth lowers light and heat but lets air and rain through. Many Australian growers use both, with film on the roof and knitted shadecloth or netting on the sides or over the top in summer. If you are still choosing a structure, see what is protected cropping? and our greenhouse and polytunnel structures.
Greenhouse film checklist
- Thickness suited to the structure and site exposure (for example 180 or 200 micron).
- Clear or diffused, based on the crop and your summer light levels.
- UV stabilisation rating, plus UV-open or UV-blocking if relevant.
- Anti-drip and anti-dust if condensation or dust are issues.
- Roll width covering the full arch plus fixing allowance; length plus ends.
- Fixing system and repair kit ready before installation.
Not sure which film suits your tunnels? Ask Oz Bunji for advice and a quote on berry film, diffused greenhouse film and fixings, delivered Australia-wide.
