Horticultural Glass 101

Friday, 6 March 2020 14:42:47 Europe/London

Horticultural glass in a greenhouseAs many gardeners know, the benefits of greenhouses on plant growth are vast and plentiful, offering the ability to simulate a number of climates with little effort required. Despite some minor advancements over the years, greenhouses have remained relatively unchanged, relying on the same set of principles as when they were first introduced; namely their ability to use translucent materials such as glass to create a temperate climate, able to facilitate plant growth in the healthiest and most reliable way possible.

Horticultural glass, more commonly referred to as greenhouse glass, is the traditional choice of gardeners across the world when it comes to successfully cultivating an array of plant life. It is a specialist grade of glass, usually 3mm thick and very translucent, enabling it to transmit light and heat consistently throughout the structure and delivering consistent results in plant growth.

However, in recent years, a new substitute for this type of glass has started to emerge; polycarbonate. Polycarbonate offers much of the same benefits which traditional horticultural glass does but with a few minor differences.


The gardening community is currently amidst debate over which is the most preferable material to use, but we’ve done the research so you don’t have to.

Let’s compare...

Horticultural Glass

As mentioned, horticultural glass is the conventional material of choice when it comes to greenhouse glazing. With its high level of transparency, it is commonly recognised for its ability to let in a large amount of light and disperse this throughout the structure in order to ensure a hearty and bountiful harvest.

It is also popular due to the relatively low cost involved in obtaining and installing it.

The material’s conductive properties are also quite well recognised with its ability to not only let in large amounts of heat during summer months but also allow UV rays to easily filter through the panes; all properties which contribute to good plant growth and high yield.

Horticultural glass in a greenhouse

Due to its almost tropical temperatures during the summer months, many gardeners find glass to be the advantageous for growing plants which require a more torrid climate. However, in cooler months or at night, some glass greenhouses may require heating support in order to stave away frost which could lead to plant damage.

Unfortunately, maintenance issues can also arise with the use of horticultural glass. Due to its relatively thin composition, horticultural glass can be easily damaged and therefore careful maintenance is required. If a breakage does occur, this can rapidly affect many aspects of the greenhouse set up including the overall temperature, humidity and airflow, amongst other things. Broken glass can pose dangers to both gardeners and wildlife and should be addressed carefully and with haste to avoid accidents.


Polycarbonate panelling, on the other hand, is a newer and sustainable option when it comes to greenhouse gardening. With a very small environmental impact during the manufacturing process and with the material being widely recyclable, many gardeners are now beginning to notice the advantages of using this in place of horticultural glass.

As well as its environmental advantages, polycarbonate is also useful when it comes to the growth and harvest of your plants. With good insulation properties, this can provide a consistent temperature for your plants to thrive in. Where traditional greenhouses may lose heat rapidly following sundown, polycarbonate greenhouses are known for their improved heat retention.

Perhaps one of the most decisive factors is the light emittance and temperature control which polycarbonate can provide. While glass is extremely translucent and allows light and UV to directly shine into the greenhouse, polycarbonate interacts with light particles, creating a diffused lighting effect which has been shown to be much more beneficial to the growth of plants, as supported by growertalks.com who explains that “diffuse light can have a significant positive impact on plant quality and productivity” due to its ability to penetrate the leaf canopy deeper, allowing for greater photosynthesis.

Polycarbonate greenhouse

Polycarbonate is also successful when it comes to UV filtration, allowing plants to receive the perfect level of UV exposure to facilitate growth. As any avid gardener will admit, the risk of accidental sunburn is all too frequent an issue when it comes to gardening. However, due to its composition, polycarbonate is known to act as a natural UV filter which is great for regulating the amount of UV exposure to both you and your plants. The material itself will need to be treated with a UV protector in order to prevent break down or yellowing, but this can be done with relative ease and a small budget.

Referring back to the subject of safety, polycarbonate is the obvious choice when it comes to selecting a product which is the least hazardous. Unlike glass, polycarbonate is shatter-resistant and therefore a sturdier choice, able to withstand impact from adverse weather conditions or accidental knocks. However, it is also prone to scratching, so similarly to glass greenhouses, gardeners choosing to use this material must take care and ensure that proper maintenance is upheld.

Whether you choose to use horticultural glass or polycarbonate panelling on your greenhouse, both provide their unique set of benefits. The choice is ultimately down to the individual gardener and what suits your personal circumstances.

While polycarbonate has made vast scientific advancements in recent years and seems to be the natural successor of the conventional greenhouse, the traditionalists among us may still opt to use horticultural glass. Although polycarbonate can and will do wonders for your plant life, the beauty and simplicity of a glass greenhouse is undeniable.

Regardless of your choice, maintenance is the key factor in ensuring that your harvests are rich and plentiful. With the many varieties of greenhouse available, each gardener will ultimately make their own choice on the most suitable product for themselves.

Happy gardening!

Posted in Polytunnel Construction By

Greenhouse Sensation

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