Greenhouse Glass – Best 5 Alternative Greenhouse Plastic Options

Greenhouse glass is fragile and easy to break causing heat loss in the greenhouse, and danger to the plants being grown inside. The broken greenhouse glass can also make very sharp shards and fragments of broken glass which is very dangerous especially for children or pets. Clear Polycarbonate sheets are the best alternative for replacing greenhouse glass however there are different types of polycarbonate and thicknesses to choose from.

In this guide we will help you understand the different greenhouse plastic alternatives to greenhouse glass for replacements and choose the best option for your needs. The same information below applies to using Polycarbonate sheets for Cold Frames, Sheds and other structures.

Why Should I Replace Greenhouse Glass with Clear Plastic?

• Keep safe from fragile glass with plastic glazing sheets
• Greenhouse Plastic has Excellent Impact Resistance
• Clear Polycarbonate Sheets are safe for Children and Pets
• Multiwall Polycarbonate options retain more Heat than Glass
• Lighter Weight than Glass

What Benefits You Get from Greenhouse Plastic Sheeting?

• Increase safety for Children and Pets
• No Costly Breakages like you get with Glass
• Excellent Transparency
• Ideal for Plant Growth
• Same Greenhouse Heat-Saving Effect as Glass
• Easy to Cut to Size
• Quick and Simple to Install

The 5 Best Greenhouse Glass Alternatives

If you are considering replacing broken panels or replacing the glass in your Greenhouse then you will have a wide range of plastic glazing sheet alternatives, but it is important to remember that not all clear plastic is the same; there are some massive differences which you will want to consider. Below we have set out the most important factors you should consider when making your choice between the 5 Best Greenhouse Plastic Glazing Sheets.

Choosing the right replacement greenhouse glass panels will save you money, prevent future breakages, reduce heat loss, and keep you and your family safe!

The 5 Best Greenhouse Glass Alternatives are listed below, but please be sure to check the information further down in the article to help you choose which one is right for you:

• 2mm Solid Polycarbonate Sheet
• 3mm Solid Polycarbonate Sheet
• 4mm Solid Polycarbonate Sheet
• 4mm Multiwall Polycarbonate Sheet
• 6mm Multiwall Polycarbonate Sheet

In the following 5 questions we answer some key topics to help you choose the Best Greenhouse Glass Alternative Glazing Sheet:

1. What can I use Instead of Glass in My Greenhouse?
2. What Thickness Polycarbonate is Best for a Greenhouse?
3. How strong is 2mm Polycarbonate?
4. Do Plants Grow Under Polycarbonate?
5. What are the best methods for cutting polycarbonate sheet?

 1. What can I use Instead of Glass in My Greenhouse?

There are several options to consider here, so we have set out two areas below to help you get a wider understanding of all these aspects for Greenhouse Glazing Plastics:

What are Plastic Glazing Sheets made from? 

Be Aware: Some Plastic Greenhouse Panels will break or discolour, so its important to make sure you choose a product which is made from polycarbonate, and also a product which has a UV Protection layer. Polycarbonate sheets are very strong and you are unlikely do have issues with breakage, however its important you make sure that you choose a product with the UV Protection layer, so they do not discolour and go yellow and brittle.

Top Tip: Acrylic Compared to Polycarbonate for Greenhouse Use: Acrylic is very much weaker than polycarbonate and will tend to crack under pressure or when drilling or cutting. Acrylic also breaks with impact, so always choose UV Protected polycarbonate such as Axgard for Clear Greenhouse Plastic.

Top Tip: HIPS Compared to Polycarbonate for Greenhouse Use: HIPS (sometimes known as Polystyrene or Styrene) is very much weaker than polycarbonate and will tend to crack under pressure or when drilling or cutting, or even with slight impact. Additionally, HIPS will go yellow and brittle very quickly with sunlight as it is not UV Protected, which is why we recommend that you use UV Protected polycarbonate such as Axgard or Axiome plastic for Greenhouse Windows.

Which is best; Solid Polycarbonate Sheet or Multiwall Polycarbonate Sheet?

Both options of Solid Polycarbonate or Multiwall Polycarbonate Sheets are great options, but they have different benefits depending on what type of result you want to achieve.

You can view our full ranges of Solid Multiwall Polycarbonate sheet and also Multiwall Polycarbonate Sheet where you can choose from all size and thickness options. The chart below shows which sheet type has the best result for these 10 Benefits of Multiwall and Solid Polycarbonate Sheets

Extra Info: What is the difference between Twinwall and Multiwall Polycarbonate? Essentially these are the same type of product, however twinwall polycarbonate sheets would generally indicate that the polycarbonate sheets have two layers, whereas thicker sheet options like 16mm polycarbonate sheets for example, tend to be called multiwall as they can be manufactured with multiple layers which naturally provides greater rigidity and higher heat insulation.

2. What Thickness Polycarbonate is Best For a Greenhouse?

The best thickness for Greenhouse Glass depends on the type of frame you have as to what thickness the clip or channel can accept for the glazing. You will also want to consider the size of each panel as you will want to choose a thicker glazing sheet for a larger panel to provide the needed rigidity. For example if your panels size is 400mm wide them 2mm polycarbonate sheets would be generally suited, whereas for 600mm width you may want to consider a 3mm polycarbonate glazing sheet or even 4mm for excellent strength and rigidity.  For both types of alternative greenhouse glass option we have set out the most common Greenhouse Glass thicknesses below:

Best Greenhouse Glass Thicknesses in Solid Polycarbonate:

• 2mm Clear Axgard Solid Polycarbonate
• 3mm Clear Axgard Solid Polycarbonate
• 4mm Clear Axgard Solid Polycarbonate

Best Greenhouse Glass Thicknesses in Solid Polycarbonate Multiwall:

• 4mm Clear Axiome Multiwall Polycarbonate
• 6mm Clear Axiome Multiwall Polycarbonate

3. How strong is 2mm Polycarbonate?

If you are considering a thin gauge of Polycarbonate Sheets for Greenhouse Glazing such as 2mm thickness then you may be concerned how strong this will be at such a relatively small thickness, however Polycarbonate Sheets are made from raw material which is typically 200 times the impact strength of glass of the same thickness and therefore generally reckoned to be virtually unbreakable. As long as you choose a UV Protected polycarbonate sheet, such as Axgard then 2mm polycarbonate sheets, then you should be fine for Greenhouse glazing, although you should also bear in mind flexibility of the sheet. For larger panels of 600mm wide or more, you may want to consider increasing to 3mm polycarbonate sheets which are 50% more rigid and 50% stronger than 2mm polycarbonate sheets.

4. Do Plants Grow Under Polycarbonate?

Without getting too technical about it, this is all about the light spectrum, however to make it simple, if you choose Axgard Polycarbonate sheets or Axiome Multiwall sheets they allow the correct light bandwidth of the light spectrum to pass through them for growing plants, in a similar way to glass. Plants will grow under most Polycarbonate sheets, however it is important that you choose clear glazing Sheets, as opposed to Opal or other tints, so that the best amount of light is allowed through for the best plant growth results.  

5. What are the best methods for cutting polycarbonate sheet?

Axgard or Axiome Polycarbonate sheets are easy to cut, because they are manufactured from a very strong and flexible raw material which means they won’t crack at the edges like other weaker plastics such as acrylic. You can check out our full How to Cut Axgard Glazing Sheets Video guide on this which shows step by step tips and best practices on the easiest methods for cutting polycarbonate sheets.

There is often concern about drilling Polycarbonate Sheets, that they might crack when being drilled, however by simply following the steps in this How to Drill Axgard Solid Polycarbonate Sheets Video you can avoid any common pitfalls and make sure you can drill any required holes without any breakages.

Need further Advice on Greenhouse Glass Replacements?

Our Teams are always happy to assist on our Live Chat or email shop@clearamber.com where our super friendly Teams will provide you with all the advice and support you require for your projects. You can even request a call back, and one of our experts will call you back at a time that suits you.

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