Detailed Explanation of Corrugated Plastic Sheets for Greenhouses​

As a core covering material for modern agricultural greenhouses, corrugated plastic sheets demonstrate significant advantages in balancing functionality and economy due to their unique structural design and material properties. The following analysis covers material characteristics, scenario adaptation, installation and maintenance, and other dimensions to help users fully understand their application value.​

I. Material Analysis: Characteristic Differences Among Three Main Materials​

The performance of corrugated plastic sheets depends primarily on their base materials. Currently, polycarbonate (PC), polyvinyl chloride (PVC), and polypropylene (PP) are the mainstream in the market, each with distinct applications:​

• Polycarbonate (PC) Sheets: As a high-end option, their impact resistance is comparable to “tempered glass among plastics,” capable of withstanding direct impacts from hailstones with a diameter of less than 3 cm without breaking. The light transmittance reaches 85%-90%, and after diffuse reflection through the corrugated structure, light can evenly cover all corners of the greenhouse, avoiding local burns on plants. With a wide temperature resistance range (-40℃ to +120℃), they can be stably used in cold northern regions or high-temperature greenhouses in the south. Equipped with double-sided anti-ultraviolet coatings, their service life can reach 10-15 years, making them the first choice for commercial planting bases.​

• Polyvinyl Chloride (PVC) Sheets: Costing about 30% less than PC sheets, they have a light transmittance of approximately 75%-85%. However, long-term use is prone to yellowing due to ultraviolet radiation, with light transmittance decreasing by 3%-5% annually, and a typical service life of 5-8 years. Their advantage lies in good flexibility, allowing them to be bent into arcs, making them suitable for building arched greenhouses. Additionally, their thermal insulation performance is better than PC sheets, making them more suitable for small and medium-sized vegetable greenhouses in northern winter.​

• Polypropylene (PP) Sheets: The lightest type, with a density of only 0.9g/cm³, they have excellent corrosion resistance, especially against acids and alkalis, making them suitable for greenhouses growing high-humidity crops (such as mushrooms and tropical orchids). However, they are prone to embrittlement at low temperatures and may crack below -10℃, so they are more suitable for temporary seedling sheds or seasonal planting in warm areas south of the Yangtze River.​

II. Scenario Adaptation: Precise Matching from Crop Types to Climatic Conditions​

The selection of corrugated plastic sheets should be combined with planting goals and environmental characteristics to achieve “a strategy for each location”:​

• Seedling Greenhouses: Requiring high light transmittance (≥85%) and a constant temperature environment, transparent PC sheets are preferred, paired with a double-layer structure (with an intermediate air layer thickness of ≥10mm). This can control the day-night temperature difference within 5℃, increasing seedling survival rate by more than 20%.​

• Flower Greenhouses: Sensitive to light spectra (e.g., roses require long daylight hours, while orchids prefer scattered light). PC sheets with added diffusing agents can be used, which not only ensure light transmittance but also soften light to reduce petal burns. For northern flower greenhouses, it is recommended to choose PC sheets with a thickness of ≥4mm, combined with edge sealing design, which can reduce heating energy consumption by 30% in winter.​

• Vegetable and Fruit Greenhouses: Leafy vegetables (such as lettuce) require rapid growth, and PVC sheets with high light transmittance can meet the demand; melons and fruits (such as tomatoes and cucumbers) need day-night temperature differences to promote sugar accumulation. A combination of “PC sheets + sunshade nets” can be adopted, with a shading rate of 30% at noon in summer to avoid excessive growth due to high temperatures.​

• Extreme Climate Zones: In typhoon-prone areas, PC sheets with a thickness of ≥6mm are suitable, fixed with “dovetail nails + sealant” for double protection, achieving a wind resistance rating of up to 10. In snowstorm areas, corrugated structures with strong load-bearing capacity (wave height ≥20mm) are required, capable of withstanding 50kg of snow load per square meter.​

III. Installation and Maintenance: Key Operations to Extend Service Life​

The “lightweight and easy installation” of corrugated plastic sheets is not without skills; scientific operation can avoid 80% of later problems:​

• Installation Points:​

1. Frame Adaptation: Galvanized steel or aluminum alloy frames should be used to avoid rust on metal parts in direct contact with the sheets (rust can corrode PVC/PP sheets).​

2. Fixing Method: Each sheet edge requires at least 3 fixing points with a spacing of ≤50cm. Screws must be covered with rubber gaskets to prevent sheet cracking due to thermal expansion and contraction.​

3. Drainage Design: A 5-10cm overlap should be left at the sheet joints, with a slope of ≥5° to prevent water infiltration into the greenhouse; drainage grooves can be added at the troughs to cope with heavy rain.​

• Maintenance Tips:​

• Cleaning: Wipe the surface with a soft cloth dipped in neutral detergent every spring to remove dust and bird droppings (long-term accumulation will reduce light transmittance). Do not use steel wool or strong acid cleaners (they will damage the anti-ultraviolet coating).​

• Inspection: Check if the sealant is aging before the rainy season and replace it promptly if cracks are found; reinforce loose fixings before winter to prevent cold wind from entering.​

IV. Comparison with Traditional Materials: Why They Become the Preferred Alternative?​

It can be seen from the table that corrugated plastic sheets achieve the optimal balance in the “performance-cost-lifespan” triangle: although their service life is shorter than that of glass, the installation cost is only 1/3 of that of glass; although the price per square meter is higher than that of films, there is no need for annual replacement, resulting in lower long-term comprehensive costs.