Greenhouse Covers: A Comprehensive Guide


Understanding Greenhouse Covers

Greetings, green-thumbs and gardening enthusiasts! Today, we’re going to delve into an important aspect of greenhouses that often goes underappreciated: the greenhouse cover. As someone who has spent years working with greenhouses and nurturing plants of all shapes and sizes, I’m eager to share my knowledge on this vital component. Without further ado, let’s unpack the world of greenhouse covers!

Greenhouse covers are essential in creating the perfect environment for your plants to thrive in. They act as the shield that stands between your delicate, green friends and the often harsh and unpredictable world outside. But what exactly are they, how do they work, and why are they so important? Let’s find out.

Why Do Greenhouses Need Covers? 

The Role of Greenhouse Covers

Greenhouse covers are much more than just the physical barrier that encases your plant paradise. They serve an important function in creating an optimal microclimate that fosters the growth and development of your plants. Essentially, they act as the controller of the environment inside your greenhouse.

The primary role of a greenhouse cover is to admit as much sunlight as possible, yet prevent the escape of heat – a phenomenon known as the “greenhouse effect”. They absorb the sun’s energy and convert it into thermal energy, maintaining a warm and stable climate inside your greenhouse.

Climate Control and Plant Health

But that’s not all! Besides regulating temperature, greenhouse covers also play a part in maintaining optimal humidity levels within the greenhouse. They prevent excessive evaporation, helping to keep the air moist and suitable for your plants.

Greenhouse covers also protect your green oasis from the onslaught of unfavorable weather conditions, pests, and diseases. By shielding the inside from wind, snow, hail, or excessive rainfall, they help maintain a consistent environment that your plants can prosper in.

A carefully selected and well-maintained cover can significantly enhance the health and productivity of your plants, leading to greener leaves, more abundant flowers, and larger, juicier fruits.

Types of Greenhouse Covers 

Glass Greenhouse Covers 

Now, let’s take a look at the different types of greenhouse covers you can choose from. Starting with the classic: glass. For centuries, gardeners have leaned on glass to create stunning, efficient greenhouses. Glass is durable, offers high light transmission, and gives your greenhouse an elegant, aesthetic appeal that’s hard to beat.

However, it’s worth noting that glass greenhouse covers are typically more expensive and may require a sturdy frame to support their weight. They can also be challenging to install and replace, which may be a consideration for beginners or those looking for a more hassle-free option.

Plastic Greenhouse Covers 

Next up, we have the ever-popular plastic covers. These covers are lightweight, cost-effective, and relatively easy to install and replace. They also offer excellent light transmission, similar to glass, but with the added benefit of being less prone to breakage.

Plastic greenhouse covers come in a variety of types, including polyethylene, polycarbonate, and acrylic, each with its own set of pros and cons. For example, while polyethylene is cost-effective and easy to replace, it tends to degrade faster under UV exposure and might need to be replaced every few years. On the other hand, polycarbonate is more durable and offers better insulation but is more expensive.

Fabric Greenhouse Covers 

Last but not least, we have fabric covers. These are made from materials like shade cloth or row cover fabric and are primarily used to protect plants from extreme sunlight, wind, or cold. They’re typically used in combination with other covers or for specific periods, like during the peak of summer or the chilliest winter months.

While fabric covers don’t offer as much control over temperature and humidity as glass or plastic, they can be a fantastic choice for specific uses or certain types of plants. Plus, they’re usually easy to install and adjust, giving you more flexibility in managing your greenhouse.


Choosing the Right Greenhouse Cover

Consider Your Climate 

When it comes to selecting the right cover for your greenhouse, a key factor to consider is your local climate. If you’re in an area that gets a lot of sun and heat, a cover with good light diffusion properties might be ideal. It’ll scatter sunlight evenly and prevent your plants from getting scorched.

On the other hand, if you’re in a colder region, you might prefer a cover that provides excellent insulation, like double-layered polycarbonate, to keep your plants cozy during those chilly months.

Think About Your Plants 

The types of plants you want to grow also influence your choice of cover. Different plants have different requirements when it comes to light, temperature, and humidity. Make sure to understand what your plants need and choose a cover that helps create the perfect environment for them.

Maintenance and Durability 

How much time and effort are you willing to spend on maintaining your greenhouse cover? If you’re okay with regular upkeep, a plastic cover like polyethylene might work for you. But, if you’re looking for something more long-lasting, a glass or polycarbonate cover could be a better fit.

Caring for Your Greenhouse Cover

Regular Cleaning 

To ensure your greenhouse cover remains effective, it’s crucial to maintain it well. Regular cleaning is key. Dirt and debris can block sunlight from entering your greenhouse, affecting the amount of light your plants receive.

Whether it’s glass, plastic, or fabric, make sure to clean your cover regularly, but gently! Use a soft brush or sponge and a mild cleaning solution to prevent any damage.

Check for Damage 

Also, keep an eye out for signs of wear and tear. Over time, greenhouse covers can develop cracks or holes, or they might start to become discolored or cloudy. This can reduce their effectiveness and might mean it’s time for a replacement.


In the world of greenhouses, the humble cover plays an incredibly important role. It not only protects your plants from the elements but also helps create the ideal conditions for them to thrive. From classic glass and versatile plastic to protective fabric, there’s a greenhouse cover to suit every gardener’s needs and preferences.

Remember, it’s not just about choosing the right cover, but also about taking care of it to ensure it continues to serve its purpose effectively. So, whether you’re a beginner setting up your first greenhouse or a seasoned gardener looking to upgrade, I hope this guide helps you in your gardening journey. Happy gardening, folks!


1. Can I use different types of covers in the same greenhouse? 

Yes, you can! In fact, using a combination of covers can be a great way to optimize your greenhouse environment. For example, you could use a glass or plastic cover for the main structure, then use fabric covers during particularly hot or cold periods for added protection.

2. How often should I clean my greenhouse cover? 

Ideally, you should clean your greenhouse cover at least twice a year: once before spring and once before fall. However, if you notice that the cover is getting dirty or if your plants seem to be struggling, it might be a good idea to clean it more frequently.

3. How long do plastic greenhouse covers last?

The lifespan of a plastic greenhouse cover largely depends on the type of plastic used and how well it’s maintained. On average, polyethylene covers tend to last 2-3 years, while polycarbonate and acrylic covers can last up to 10 years or more with proper care.

4. Is a glass greenhouse cover better than a plastic one? 

Neither is inherently “better” than the other. Both have their own pros and cons. Glass is more durable and aesthetically pleasing, but it’s also more expensive and requires a sturdy frame. Plastic is more cost-effective and easier to install, but it might not last as long. The best choice depends on your specific needs and circumstances.

5. Can I use a greenhouse without a cover?

Technically, you could, but it wouldn’t serve the same purpose. The cover is crucial for controlling the environment inside the greenhouse. Without it, you lose control over factors like temperature, humidity, and protection from pests or extreme weather conditions. It’s like having a car without a roof – it’ll still work, but it won’t provide the same level of comfort and protection.

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John Shaw

In this blog, we won't just stop at the basics of greenhouse gardening. Whether you're planning to set up your first tabletop greenhouse or looking to optimize a sprawling garden, my posts will cater to a wide range of interests and skill levels. I'll share practical tips and innovative solutions to common gardening challenges. Thank you for being a part of this journey. Through our shared passion for horticulture, we can grow, not only plants, but also a vibrant community of gardeners. I'm excited to see where our greenhouse adventures take us. Happy gardening!

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