Best Polycarbonate for a Greenhouse

Building a greenhouse is an investment, and choosing the best polycarbonate for a greenhouse is key to making sure it lasts, insulates well, and provides the right amount of light for healthy plant growth.

With so many options available, it's important to understand what makes polycarbonate a good choice, which type works best, and how thickness and color affect performance.

We have spent years helping customers select the right greenhouse materials for their kits, and based on our experience, twin-wall polycarbonate stands out as the best option for durability, insulation, and cost-effectiveness.

In this article, we'll break down the benefits of polycarbonate, compare different types, explain which thickness is ideal for various climates, and help you decide on the best color for optimal plant growth.

Whether you're looking to extend your growing season, protect plants from harsh weather, or build a greenhouse that lasts for years, we'll cover everything you need to know to make the right choice.

What this article covers:

• What Is Polycarbonate?
• What Is the Best Type of Polycarbonate for Greenhouses?
• What Is the Best Polycarbonate Thickness for a Greenhouse?
• What Color Polycarbonate Is Best for a Greenhouse?
  
• Best Polycarbonate for Greenhouses (FAQs)

What Is Polycarbonate?

Polycarbonate is a strong, lightweight plastic used for greenhouse glazing—the panels that make up the walls and roof. It's a modern alternative to traditional glass and is favored for its durability, impact resistance, and insulation properties.

Polycarbonate panels are virtually unbreakable and very easy to install, especially with our panelized greenhouse kits. It also offers fantastic heat retention, making it perfect for growing plants year-round.

It can even be used alongside the best greenhouse glass in the same structure so that you can get the best of both worlds for your greenhouse.

Why Is Polycarbonate Good For Greenhouses?

Polycarbonate has become one of the best materials for greenhouse because it is highly durable and won't shatter. It allows plenty of light through, ensuring plants get the energy they need to grow. Its heat retention properties help maintain a stable growing environment, reducing heating costs in colder months.

Polycarbonate is lightweight, making installation easier and more manageable for DIY builders. Many polycarbonate sheets come with built-in UV protection, preventing harmful rays from damaging plants while still letting in the necessary light for photosynthesis.

From our experience, polycarbonate is one of the most practical and cost-effective choices for greenhouse owners, making it a top choice for the best greenhouse kits.

What Is the Best Type of Polycarbonate for Greenhouses?

When selecting the best polycarbonate for a greenhouse, it's important to compare the two main types: solid polycarbonate and twin-wall polycarbonate. Both have unique benefits, but one clearly stands out as the best choice for greenhouse applications.

Solid Polycarbonate

Solid polycarbonate is often chosen for its crystal-clear appearance. It closely resembles glass, offering high light transmission and a sleek, modern look. It's impact-resistant and shatterproof, making it a safe option. If aesthetics are a top priority, solid polycarbonate provides a professional, polished look.

However, while solid polycarbonate has high clarity, it lacks insulation efficiency. Without an internal structure to trap air, it does not retain heat as well as twin-wall polycarbonate. This makes it less energy-efficient, especially in colder climates where maintaining warmth inside the greenhouse is critical.

Solid polycarbonate is also heavier and more expensive than twin-wall polycarbonate. While it offers strength and durability, the higher cost and lower insulation value make it less practical for greenhouse use, especially for large-scale or year-round growing.

Twin-Wall Polycarbonate

After putting both materials to the test, twin-wall polycarbonate is our top recommendation for greenhouses.

This type of polycarbonate is designed with two layers and a hollow structure in between. The air pockets inside create a natural insulating barrier, which significantly improves heat retention.

The insulation benefits of twin-wall polycarbonate help maintain a stable growing environment, which is essential for plant health. It reduces heat loss in the winter and minimizes excessive heat buildup in the summer. This helps lower energy costs for those using heating or cooling systems, making it the more cost-effective option in the long run.

Twin-wall polycarbonate is also lighter than solid polycarbonate, making it easier to handle and install. Despite its lightweight nature, it remains strong and highly impact-resistant. The layered design provides better durability against harsh weather, including strong winds, hail, and heavy snowfall.

In terms of affordability, twin-wall polycarbonate is the best value for greenhouse owners. Twin-wall polycarbonate greenhouses offer a balance of strength, insulation, and cost-efficiency that solid polycarbonate simply cannot match

What Is the Best Polycarbonate Thickness for a Greenhouse?

Polycarbonate sheets come in a variety of thicknesses, and choosing the best greenhouse panels depends on climate conditions, greenhouse size, and insulation needs.

The thicker the polycarbonate, the better it insulates and protects against extreme weather. However, thicker panels are also heavier and cost more, so it's important to find the right balance between durability and cost.

4mm To 6mm Polycarbonate

For gardeners in regions with mild winters and minimal wind or snow, 4mm to 6mm polycarbonate can be a cost-effective choice. These thinner panels allow plenty of sunlight through while still offering basic protection.

However, thinner sheets provide limited insulation, meaning they won't retain heat well in colder months. This makes them better suited for seasonal greenhouses or temporary structures rather than year-round growing.

If you live in an area where temperatures rarely drop below freezing, 6mm twin-wall polycarbonate can work well, but it may require extra reinforcement to withstand strong winds.

8mm To 10mm Polycarbonate

For gardeners looking for a long-term greenhouse solution with solid durability and insulation, 8mm to 10mm twin-wall polycarbonate is the best option.

It provides significantly better heat retention than thinner sheets, helping maintain stable temperatures inside the greenhouse. This is particularly useful for those who want to extend their growing season into the colder months.

In moderate climates, 8mm twin-wall polycarbonate is a good all-around choice, offering a strong balance of light transmission, insulation, and durability.

For regions with occasional storms or colder winters, 10mm twin-wall polycarbonate provides extra protection against harsh weather while keeping heating costs down.

What Thickness Is Best For Your Greenhouse?

For most home gardeners, 8mm or 10mm twin-wall polycarbonate is ideal. It provides the best mix of durability, insulation, and affordability without significantly increasing costs. For year-round use in moderate climates, 8mm to 10mm is the best balance of insulation and cost.

What Color Polycarbonate Is Best for a Greenhouse?

The color of polycarbonate panels affects light transmission, which directly impacts plant growth. Clear polycarbonate is the best choice for most greenhouses because it allows the highest level of light penetration, up to 90%.

This ensures plants receive adequate sunlight for photosynthesis and growth. More light means healthier plants and less reliance on artificial lighting. In extremely sunny areas, too much direct sunlight can lead to overheating inside the greenhouse.

A good solution is to incorporate a mix of clear and opal (milky white) polycarbonate panels. Opal panels diffuse light, reducing intense heat while still allowing plenty of brightness inside. Some greenhouse owners also use removable shading panels for better light control.

While clear is the best all-around choice, certain situations may call for slight modifications. If your goal is maximum plant growth, stick with clear polycarbonate. If heat control is a concern, consider mixing in a few opal panels for better shading and temperature regulation.

Conclusion

Choosing the best polycarbonate for a greenhouse comes down to durability, insulation, and light transmission. Twin-wall polycarbonate stands out as the top choice for most growers, offering superior heat retention, strength against harsh weather, and better cost efficiency compared to solid polycarbonate.

Clear polycarbonate provides the highest light transmission, making it the best option for plant growth, while opal panels can help with heat regulation in particularly sunny climates.

Investing in quality polycarbonate ensures your greenhouse will be efficient, long-lasting, and capable of supporting healthy plant growth year-round. If you're ready to build or upgrade your greenhouse, shop with Homestead Supplier today and get the best polycarbonate panels for your needs.

Best Polycarbonate for Greenhouses (FAQs)

How long does polycarbonate last in a greenhouse?

High-quality polycarbonate panels can last 10 to 20 years, depending on the manufacturer, UV protection, and climate conditions. Choosing panels with UV-resistant coatings will extend their lifespan and prevent yellowing or brittleness over time.

How do I clean polycarbonate greenhouse panels?

Use mild soapy water and a soft cloth or sponge to clean polycarbonate panels. Avoid abrasive cleaners, ammonia-based products, and harsh scrubbing tools, as they can scratch the surface and reduce light transmission.

Does polycarbonate scratch easily?

Polycarbonate is more scratch-resistant than glass but can still develop scratches over time. To minimize damage, clean it with a soft cloth and avoid abrasive materials or harsh chemicals.

Will polycarbonate turn yellow over time?

Lower-quality polycarbonate without UV protection can yellow and degrade after prolonged sun exposure. High-quality panels with UV-resistant coatings will maintain clarity for 10-20 years with proper care.