What Is Shading Film?
A shading film is a covering material designed to control light transmission, varying from those allowing only 15% light transmission to those blocking nearly 100%. It’s primarily used in vegetable and flower cultivation, and also in livestock barns.
Uses of Shading Film
Shading films are used in plastic greenhouses, agricultural hangars, and work sheds, stretched over roofs and sides. They are also applied to building windows for UV and sunlight protection and to prevent glass shattering.
1. Light-Shielding Rate of About 20%
Shading films with a 20% light-shielding rate are used to protect summer vegetable seedlings from harsh sunlight, aiding in the germination of certain crops like carrots and preventing damage to vegetables like tomatoes and cucumbers.
2. Light-Shielding Rate of About 80%
Those with an 80% rate are beneficial during seedling stages, reducing soil drying and irrigation work. They’re used for crops that germinate in the dark, such as rice and onion seedlings.
3. Light-Shielding Rate Close to 100%
Films with nearly 100% light-shielding create artificial darkness, suitable for shiitake mushroom cultivation and chrysanthemum shade cultivation, which requires controlled day-morning hours.
Features of Shading Film
Pros
Shading films offer light and heat control, reducing greenhouse temperatures and protecting plants. They’re also weather-resistant and long-lasting, reducing the need for frequent replacements.
Cons
Installation can be challenging for an individual, often requiring multiple people. The thin material demands careful handling to avoid damage, and high-elevation work requires safety measures to prevent accidents.
Types of Shading Film
1. Classification by Structure
Varieties include three-layer silver polyethylene types and multilayer agricultural PO films with an aluminum particle layer. Some films are white on the front and grayish on the back, suitable for crops needing reduced internal temperature and brightness.
2. Classification by Thickness
Thickness ranges from ultra-thin at 0.04 mm to 0.15 mm. Thinner films are used in tunnels or as a solid layer for seedlings, while thicker films cover entire greenhouses.
3. Classification by Width
Available in various widths, from narrow 1.35m and 1.5m to wide 12m options. Wider films, made by joining multiple sheets, may require repair tape for age-related damages.
How to Select Shading Film
Choose based on the shading rate suitable for the target crops. Consider heat retention properties, ease of operation, and physical durability to maintain workability. For vegetables where coloration is key, low light shading ratios are preferred.
Other Information on Shading Film
Usage Tips
To ensure durability, follow these guidelines:
- Verify the correct orientation of the film before stretching.
- Store in a cool, dark place to prevent fusion.
- In summer, stretch loosely to avoid sagging; in winter, tighten to accommodate summer loosening.
- Avoid sulfur sprays or fumigation inside greenhouses.
- Use appropriate bands for agricultural purposes to avoid tearing.