Glass Vs Polycarbonate Best Greenhouse Covering for Growth

In the pursuit of higher yields and lower operational costs for commercial greenhouse operations, selecting the right covering material is crucial. Much like providing an ideal habitat for plants, greenhouse covering materials directly impact critical growth factors such as light transmission, temperature, and humidity. This article provides a detailed comparison between glass and polycarbonate greenhouses to help growers make informed decisions tailored to their specific needs.

Light is the fundamental driver of photosynthesis, and greenhouse coverings significantly influence both the quantity and quality of light penetration. Understanding the optical properties of different materials is essential for optimal selection.

Glass greenhouses are renowned for their exceptional light transmission, typically achieving over 90% transparency. This maximizes sunlight penetration, providing ample energy for photosynthesis—particularly beneficial for light-loving crops like tomatoes and peppers in high-latitude regions or during low-light seasons.

Polycarbonate greenhouses offer slightly lower light transmission (80-85%) but excel at diffusing direct sunlight into a uniform distribution. This reduces shadows and prevents leaf scorching, making them ideal for shade-sensitive crops like lettuce and herbs, especially during summer heat.

Greenhouses face constant exposure to harsh weather conditions, making durability a critical factor.

Polycarbonate boasts exceptional impact resistance, withstanding hail, strong winds, and accidental impacts without shattering. Its structural integrity remains intact even in extreme conditions, offering reliable protection—particularly in storm-prone regions.

While traditional glass is fragile, tempered glass technology has significantly improved its strength. Though still less impact-resistant than polycarbonate, tempered glass can withstand common weather events and breaks into safer, blunt fragments.

Maintaining stable temperatures is vital for plant health and energy efficiency.

Multi-wall polycarbonate panels provide outstanding insulation through air pockets between layers. Using 8mm panels for walls and 10mm for roofs can reduce heating costs by up to 25% compared to single-pane glass.

Double-glazing and Low-E coatings have enhanced glass's insulation properties, though it still trails polycarbonate in thermal performance. Additional winter strategies like thermal curtains and supplemental heating are often necessary for glass structures.

Different plants have unique requirements that influence material selection:

• High-light crops: Tomatoes, peppers, and cucumbers thrive under glass's superior transparency
• Shade-tolerant crops: Lettuce and herbs benefit from polycarbonate's diffused light
• Climbing plants: Glass greenhouses typically offer greater height for vertical growth

Regional weather patterns significantly impact material performance:

• Cold climates: Polycarbonate's insulation shines in northern regions with harsh winters
• Hot climates: Glass requires additional ventilation and shading to prevent overheating
• Storm-prone areas: Polycarbonate's impact resistance is invaluable for hail and high winds

The choice between glass and polycarbonate greenhouses involves careful evaluation of multiple factors including light requirements, durability, insulation needs, budget constraints, crop types, and local climate conditions. Commercial growers must weigh these considerations against their specific operational goals to select the covering material that will optimize productivity and profitability.