Greenhouse Cover Materials: Plastic vs Glass

When selecting materials to cover a greenhouse, the choice between plastic and glass is often debated. Each material has its own set of advantages and disadvantages. This article aims to provide a comprehensive guide, comparing the use of plastic to cover a greenhouse with the use of glass, and examining the key factors to consider for the perfect greenhouse cover.

Can You Use Plastic to Cover a Greenhouse?

Yes, plastic can be used to cover a greenhouse, being a common choice for many greenhouse structures. This type of covering offers a practical and cost-effective solution, but it comes with specific considerations that must be taken into account to ensure its effectiveness and durability.

Types of Plastic

Polyethylene Film:

Polyethylene film is the most commonly used material for greenhouse covering. It is available in different thicknesses, typically ranging from 4 to 6 mils. This material provides excellent light transmission and insulation. However, it is important to note that polyethylene film degrades over time due to UV exposure, meaning it needs to be replaced every few years.

Polycarbonate Panels:

Polycarbonate panels are more durable than polyethylene film. They are available in twin-wall or multi-wall options, which offer improved insulation. Although they are more expensive, polycarbonate panels can last for many years without needing replacement.

Polyvinyl Chloride (PVC):

Polyvinyl chloride is used in some greenhouse applications, particularly for smaller structures. It offers good durability but is less common than polyethylene and is not often the first choice for larger greenhouses.

Benefits of Using Plastic

Light Transmission: Plastic covers can allow a high percentage of sunlight to penetrate, which is crucial for plant growth. Insulation: Depending on the type and thickness of the plastic, it can help retain heat, making it suitable for extending the growing season. Cost-Effective: Generally, plastic coverings are more affordable than glass or other materials.

Considerations

Durability: Plastic can degrade over time, especially when exposed to UV light. Regular inspection and replacement may be necessary to maintain its effectiveness. Condensation: Plastic can create a humid environment inside the greenhouse, so proper ventilation is crucial to prevent mold and mildew. Temperature Control: In hot weather, plastic can trap heat, requiring shading or ventilation to maintain manageable temperatures.

Why Not Use Plastic?

While plastic offers several advantages, it can also have drawbacks. One significant issue is that plastic can disintegrate under prolonged exposure to solar radiation. Additionally, many old greenhouses with plastic roofs have been observed to have damaged or destroyed plastic covers, highlighting the need for regular maintenance and replacement.

Alternative Options: Glass

For those seeking a more durable and long-lasting option, glass is a viable alternative to plastic. Glass offers several benefits, including enhanced durability, aesthetic appeal, and ease of cleaning. However, it can be more expensive.

Advantages of Using Glass for Greenhouse Cover

Durability: Glass does not degrade as rapidly as plastic, making it a more long-lasting option. Aesthetic Appeal: Glass provides a clear and aesthetically pleasing cover for the greenhouse. Ease of Cleaning: Glass is easy to clean, making it ideal for areas where frequent cleaning is necessary.

Limitations of Glass

Initial Cost: Glass can be more expensive than plastic, making it a more significant initial investment. Weight: Glass is heavy, which can pose challenges in terms of structural support. Heat Insulation: While glass provides excellent insulation, it may require additional shading in hot climates.

Walipinis as an Alternative

Walipinis, also known as earth berm greenhouses, are another option worth considering. They are better suited for most climates and can be a sustainable and efficient solution. Earth berm greenhouses are typically buried into the earth, providing natural insulation and reducing the need for additional heating or cooling.

While plastic is a practical and widely used option for greenhouse coverings, it is essential to carefully consider the specific needs and requirements of your greenhouse. Factors such as cost, durability, environmental conditions, and maintenance should be taken into account to determine the most suitable cover material for your needs.