Plastic for Your Greenhouse?

The ideal greenhouse material needs to let in plenty of light while standing up to Australia’s harsh sun, strong winds, and occasional hail. It should also provide good insulation to help maintain a stable growing environment.

Here’s how the most common plastic glazing materials compare.

Whether you’re building a backyard greenhouse or replacing damaged glazing, choosing the right plastic can make a significant difference to plant growth, durability, and long-term maintenance.

Polycarbonate – The Best All-Round Choice

For most Australian greenhouses, polycarbonate is the best overall glazing material.

Its exceptional impact resistance means it can withstand hail, accidental impacts, and harsh weather that would easily break glass. It also offers excellent UV resistance and a long service life outdoors.

Twinwall polycarbonate provides another major advantage by trapping air between its layers, improving insulation and helping maintain more consistent temperatures throughout the day and night.

Best suited for:

• Home greenhouses
• Commercial greenhouses
• Vegetable gardens
• Schools
• Garden centres

Benefits

Available in clear, opal, and twinwall options

• Outstanding impact resistance

• Excellent light transmission

• UV protected

• Lightweight

• Easy to install

Acrylic – Maximum Light and Clarity

If your priority is achieving the highest possible light transmission, acrylic is an excellent option.

Clear acrylic transmits up to 92% of visible light, making it one of the clearest glazing materials available. It also maintains its clarity exceptionally well over many years of outdoor exposure.

Although stronger than glass, acrylic is not as impact resistant as polycarbonate, making it better suited to areas where hail or vandalism is less of a concern.

Best suited for:

• Display greenhouses
• Botanical gardens
• Decorative garden structures
• Low-impact environments

Benefits

• Exceptional clarity
• Excellent weather resistance
• UV stable
• Attractive appearance
• Long-lasting outdoors

Polycarbonate vs Acrylic

Which Thickness Should You Choose?

The right thickness depends on your greenhouse size and location.

• 3 mm – Small cold frames and garden covers
• 4.5–6 mm – Small backyard greenhouses
• Twinwall 6–10 mm – Most residential greenhouses
• 10 mm+ Twinwall – Larger structures or colder climates

If your area experiences frequent hail or strong winds, choosing a thicker panel will improve durability.

Frequently Asked Questions

Is acrylic stronger than glass?

Yes. Acrylic is typically around 10–20 times more impact resistant than standard glass while weighing about half as much.

Is polycarbonate stronger than acrylic?

Yes. Polycarbonate offers significantly higher impact resistance and is often chosen where safety or vandal resistance is important.

Which lets in more sunlight?

Acrylic provides the highest light transmission, reaching up to approximately 92%.

Which insulates better?

Twinwall polycarbonate offers the best insulation because of the air pockets between the layers.

Can both be cut to size?

Yes. Both acrylic and polycarbonate sheets can be supplied cut to size, making installation quicker and reducing waste.