Polycarbonate is one of the most popular clear plastics for a greenhouse. For a long time glass used to be the only glazing option but in recent years plastic structures took over. Buying or building a plastic greenhouse is very cost-effective. Also, plastic covers don’t break into long sharp shards.
However, if you prefer glass due to its aesthetic, there are 7 options to choose from. Moreover, the choice of glazing material depends on the type of greenhouse frame. The traditional option is wooden frame and glass cover. Today, you will most likely to see a combination of aluminum frame with polycarbonate panels.
There is no doubt that polycarbonate is great for outdoor use but is it a best plastic for greenhouse?
The main pros of polycarbonate greenhouse are that it is flame resistant, UV resistant, durable, lightweight and inexpensive. Cons are that it is easy to scratch, can get dusty, algae and condensation can also develop. However, with regular cleanings you can keep it in a perfect condition.
In this blog post we will talk about the pros and cons of polycarbonate greenhouse, so you can decide if it is a suitable option for you. When applicable, we are going to compare it with glass and other plastics.
Pros of Polycarbonate Greenhouse:
Polycarbonate is much stronger than glass with a much greater impact resistance. That is because polycarbonate comes in both rigid and flexible grades. So, a flexible plastic won’t crack easily under stress. It makes them unbreakable and able to withstand massive force.
For example, polycarbonate is used to manufacture bulletproof windows and police shields. When comparing to glass, polycarbonate has 250 times the impact resistance of glass. In comparison, other plastics like acrylic has only 10 times the impact resistance of glass.
Polycarbonate makes a perfect plastic for a greenhouse because it blocks UV rays and lets in sunlight and heat. This type of plastic has light transmittance of 88%. Moreover, it can also be in clear and opaque shades. However, polycarbonate cannot be polished to restore its clarity.
Polycarbonate can come in a few colors. Although green plastic cover is widely used for greenhouse, it filters out green light. Plants don’t use it but it is better to let in full spectrum of light which can also heat the structure. The translucency or transparency of plastic can stimulate plant growth at different developmental stages.
So, it doesn’t mean that greenhouse plastic have to be clear. For example, many plants benefit from diffused light. Twin-wall polycarbonate has cellular structure that diffuses direct sunlight. Go for a frosted polycarbonate greenhouse if you want to have a permanent home for your plants.
The ability to retain heat makes polycarbonate a perfect material for greenhouses. The popular choice is twin-wall polycarbonate. It has double glazing effect which prevents heat from escaping. Choose 3 or 4 mm polycarbonate thickness for greenhouse sides and 10 mm thick plastic for roof.
Also, polycarbonate is lightweight. That means that you can cut it to size easily with hand saw. Moreover, being lightweight makes it very easy to work with. It is also easy to transport without worrying that it can break. Finally, it is very quick and easy to assemble in comparison to glass.
Polycarbonate is weather resistant, so your greenhouse is going to withstand harsh environment. Burning sun, snow and rain – you name it and polycarbonate is not going to show a sign of discoloration for many years.
Moreover, it is highly resistant to high heats and low temperatures. In addition, polycarbonate has low flammability, so it is safe to use in garden areas where barbecues take place. Combination of these factors makes polycarbonate a perfect material for outdoor use.
One of the best pros of purchasing a polycarbonate greenhouse is that it’s super easy to clean! All you need is a micro fiber or 100% cotton cloth and a solution of warm soapy water. Although it has high chemical resistance, don’t clean it with solvents.
It is going to be enough to give it a quick clean every week. Once you wash it with soapy water, give it a good rinse and dry with a soft cloth. It is important to dry it right away to prevent water spots which can affect light transmission.
Problems with polycarbonate greenhouses
Prone to scratching
Unfortunately, polycarbonate can suffer scratches. So, don’t use abrasive cleaning materials for maintenance. Also, don’t scrub polycarbonate panels when cleaning. Avoid touching it with anything made from abrasive binding agents. So you need to be careful when using your gardening tools.
It is not easy to repair scratches on polycarbonate. Moreover, it is also prone to marring. In severe cases, denting can also occur especially if you are not cautious. So, as long as you stick with the care requirements, polycarbonate will stay in a good shape.
One of the disadvantages of twin-wall polycarbonate panels is that dust can accumulate between the panels. It can be quite tricky to get rid of it. Also, if you skip weekly cleaning, dust and dirt can build up on the surface which can affect the light transmission.
Also, if you skip cleaning, dust and dirt can even scratch the surface. However, you can prevent dust accumulations. Just seal the ends with tape or you can buy U channel to cap off the ends. As a rule of thumb, clean the outside and inside of polycarbonate greenhouse annually.
If you fail to keep up with weekly maintenance algae can quickly develop and permanently stain polycarbonate panels. The bad news is that it can stain both inside and outside of the structure. Needless to say that it is going to affect light transmission.
Similarly to dust accumulation, algae can grow between the panels. If that happens, it is nearly impossible to clean. You need to think about it before hand. Cap off polycarbonate by putting a foil tape on the top of the sheets and then cover with a U channel.
Condensation is of the most common problems with twin-wall polycarbonate greenhouses. It can easily develop in between the plastic layers. As a result, it significantly reduces light transmission and accelerates development of algae.
To prevent moisture build ups, you need to use vent tape for the bottom of the sheets. Cover it with the U channel and drill the holes in the bottom of the U. That way moisture will drain through these holes. Failure to do so results in moisture accumulation and development of algae.
To sum up, polycarbonate is a great material for a greenhouse. It is lightweight, so it is going to be easy to transport to your location and assemble in a few hours. You don’t need to worry about it breaking or cracking. Also, it will withstand harsh weather conditions.
However, you would need to look after the panels. Giving them a wash on a weekly basis to prevent algae and dust accumulations. Taking extra care of the cover in winter. If you follow these recommendations, you will enjoy greenhouse gardening for many years.
What do you think about polycarbonate greenhouse? Share your opinion in the comments section below!
Happy Growing 🙂