For decades gardens all over Britain have been filled with glass greenhouses and cold frames within which an abundance of plants at various stages of development have flourished. Now it seems us Brit’s have been missing a trick, many gardeners across Europe, especially in Germany have been switching from glass in their greenhouses and cold frames to polycarbonate instead.
Polycarbonate greenhouses are cheaper, are easy to assemble and have recently had a face-lift in design making them an attractive alternative to the glass greenhouse. With so many young people on tight budgets now attempting to grow their own, a cheaper polycarbonate greenhouse will allow these folk to enjoy their own produce all year round!
The Polycarbonate greenhouses of the past as you may remember did have their drawbacks however scientists have developed new coatings and processes enabling this product to become a strong competitor against glass. One key advantage over glass is the fact that polycarbonate is pretty unbreakable. Having tougher windows on both your greenhouse and cold frame will save you money and bring you piece of mind especially if you have young children/grandchildren running around in your garden playing ball games.
In terms of insulation, the higher the value of R the better the substance is at insulating your plants. Outdoor gardening glass which is generally 3mm thick can be measured as having a value of 0.93, if you compare this with 4mm twin wall polycarbonate which is most popular in Germany this has a value of 1.42. This shows the Polycarbonate is much more efficient when it comes to insulating your greenhouse and retaining the heat radiated from the ground at night time.
One area that glass wins in is the amount of light that gets through to your plants. 3mm glass allows 97-98% of light to reach your plants where as single-skin polycarbonate allows 94-96%, that may not seem too big a difference, however if you are planning to use 4mm polycarbonate because of its insulating qualities the amount of light your plants will receive falls to 80-84% which is a significant decrease. However for you boffins out there this is not as bad as it sounds, with twin walled polycarbonate light is scattered when it passes through the wall making it more diffuse which allows the light to reach areas that glass would not allow and this in itself will benefit your young foliage.
As I mentioned earlier polycarbonate is tougher than glass and less likely to break, however surprisingly it is also far lighter meaning that when used in your greenhouse roof it requires far less timber to support it which in turn allows more light penetration into your greenhouse and reduces draughts.
To summarise, polycarbonate greenhouses and cold frames are a fantastic alternative to glass greenhouses. With better light distribution, insulation and reduced cost they will become a front runner in the greenhouse and cold frame market in years to come. Although the design of these outdoor structures has come on a great deal, the glass greenhouse is still far more pleasing on the eye.
Happy Gardening!
Gardener Jack
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