A 200-micron greenhouse polythene sheet is approximately 0.2 mm thick. It is manufactured specifically for agricultural use and is different from ordinary plastic sheets used for construction or general packaging. Quality greenhouse film contains additives that help it withstand prolonged exposure to sunlight and changing weather conditions.
For Kenyan farmers, the right greenhouse film should provide sufficient sunlight for crop growth while protecting plants from excessive ultraviolet radiation, rain, wind, dust and some environmental stresses.
The Role of Greenhouse Polythene Sheet
The main purpose of greenhouse film is to create a controlled growing environment. It covers the greenhouse while allowing useful sunlight to reach the plants.
1. Allows Sunlight into the Greenhouse- Plants need light for photosynthesis. Greenhouse film should therefore allow enough useful light to pass through.Poor-quality or heavily aged film may become cloudy, reducing the amount of light available to plants. This can affect plant growth and overall production.
2. Protects Crops from Weather- Greenhouse film protects crops from:
- Heavy rainfall
- Strong winds
- Hail
- Excessive sunlight
- Dust
- Some temperature fluctuations
This protection allows farmers to manage production more consistently than in open-field farming.
3. Helps Control the Greenhouse Environment- The film helps retain warmth inside the structure, particularly during cooler periods. During hot conditions, however, proper ventilation is still necessary because polythene alone cannot control greenhouse temperature.
4. Supports Year-Round Production- With proper irrigation, ventilation and crop management, a quality greenhouse polythene sheet allows farmers to maintain a protected production environment even when outdoor weather conditions are not favourable.
| Function | Benefit to the Farmer |
| Light transmission | Supports photosynthesis |
| Weather protection | Reduces exposure to rain and wind |
| UV treatment | Improves film durability |
| Heat retention | Helps regulate the internal environment |
| Physical barrier | Protects crops from some environmental stresses |
| Anti-drip properties | Reduces water droplets falling on crops |
Specifications of 200-Micron UV-Treated Polythene
A 200-micron greenhouse polythene sheet is one of the standard thicknesses used for commercial greenhouse construction in Kenya.
| Specification | Typical Description |
| Thickness | 200 microns |
| Thickness in millimetres | Approximately 0.20 mm |
| Main use | Greenhouse covering |
| UV treatment | Yes, for agricultural-grade film |
| Light transmission | Designed to allow useful sunlight |
| Film colour | Clear, milky or specialised colours |
| Anti-drip | Available depending on specification |
| Expected service life | Commonly around 3–5 years, depending on quality and conditions |
| Installation | Fixed using lock channels and wiggle wire |
The actual specifications can vary between manufacturers, so farmers should check the product specification before purchasing.
Why UV Treatment Matters
Ordinary plastic exposed continuously to the Kenyan sun can become brittle, yellow, crack or tear relatively quickly. UV-treated greenhouse film contains stabilisers that slow down this degradation.
This is especially important in Kenya because strong sunlight is experienced in many agricultural areas throughout the year.
A quality UV-treated film can therefore provide a longer working life than ordinary polythene. Farmers should avoid using ordinary construction polythene as a substitute for greenhouse film. Although it may initially look cheaper, it is not designed for prolonged agricultural exposure to sunlight.
Light Transmission and Diffusion Metrics
Light is one of the most important factors when selecting a greenhouse polythene sheet.
Light transmission refers to the amount of light that passes through the film. Higher transmission can provide plants with more light for photosynthesis, provided other environmental conditions are suitable.
Light diffusion, on the other hand, refers to how the film spreads incoming light rather than allowing it to pass directly in one direction.
A diffused film can distribute light more evenly throughout the greenhouse. This can be useful where direct sunlight creates strong differences between brightly lit and shaded areas.
| Feature | Meaning | Importance |
| Light transmission | Amount of light passing through film | Supports photosynthesis |
| Light diffusion | Spreading of incoming light | Improves distribution of light |
| UV stabilisation | Protection against UV degradation | Extends film life |
| Infrared properties | Influences heat retention | Helps with temperature management |
Farmers should not select film based on light transmission alone. The correct choice depends on the greenhouse design, location, crop requirements and ventilation system.
Anti-Drip and Anti-Dust Additives
Modern greenhouse films can contain special additives that improve their performance.
Anti-Drip Technology
Condensation naturally forms inside greenhouses when warm, moist air meets a cooler surface.
Without an anti-drip treatment, water can collect into droplets on the inside of the greenhouse film and fall directly onto plants. This can increase leaf wetness and contribute to an environment favourable to fungal diseases.
Anti-drip film is designed to make condensation spread across the film surface instead of forming large droplets.
Benefits of Anti-Drip Film
- Reduces dripping water onto plants.
- Helps keep foliage drier.
- Improves light conditions compared with heavy condensation.
- Supports better greenhouse hygiene.
- Helps manage humidity-related problems.
Anti-drip treatment is particularly useful in areas where night-time temperatures create significant condensation.
Anti-Dust Properties
Dust is a common issue in many Kenyan farming areas, particularly where greenhouses are located near unpaved roads or dry farmland.
Dust settling on the greenhouse film can reduce light transmission.
Some greenhouse films are manufactured with surface properties that reduce dust adhesion, making the cover easier to keep clean.
Farmers should still clean the film when necessary because no film can remain completely dust-free.
Yellow Film vs Clear Film: Which Is Best?
Greenhouse film is available in different colours and specifications. Clear and yellow films are two options that farmers may encounter when purchasing a greenhouse polythene sheet.
The best choice depends on the purpose of the greenhouse and the environmental conditions.
Clear Greenhouse Film
Clear film is designed to provide high levels of light transmission.
It is commonly selected where maximum natural light is important.
Advantages
- High light transmission.
- Suitable for general greenhouse production.
- Allows good visibility inside the greenhouse.
- Commonly available.
- Suitable for many commercial greenhouse structures.
Yellow Greenhouse Film
Yellow or coloured greenhouse films are designed to modify the light environment inside the greenhouse. Some specialised films may also be selected for particular pest-management or crop-environment purposes.
However, the colour alone should not be used to determine film quality.
| Feature | Clear Film | Yellow Film |
| Light appearance | Clear/natural | Yellow-tinted |
| Light transmission | Generally high | Depends on product |
| General greenhouse use | Very common | More specialised |
| Visibility | Excellent | Reduced compared with clear |
| Best selection basis | General production | Specific film requirements |
Cost of Greenhouse Film Per Square Meter
The cost of greenhouse polythene varies according to thickness, UV treatment, film quality, width, additives and supplier.
For budgeting purposes, farmers should normally calculate the amount of film required based on the actual greenhouse surface area, not simply the floor area.
For example, an 8×30m greenhouse has a floor area of:
8 × 30 = 240 square metres
However, the amount of covering material required will be greater than 240 square metres because the film must cover the roof, sides and end walls.
The cost of greenhouse polythene sheet per square meter is at 120 Kshs
| Greenhouse Feature | Effect on Film Requirement |
| Greenhouse length | Longer structure requires more film |
| Greenhouse width | Increases roof covering area |
| Roof design | Curved roofs require additional surface area |
| Side walls | Require separate covering |
| End walls | Add to total film requirement |
| Overlap allowance | Extra film is needed for secure installation |
| Locking allowance | Additional material is needed around profiles |
As a general market budgeting guide, 200-micron UV-treated greenhouse film may range around Kshs 120-200 per square metre, depending on quality, supplier and purchase quantity. Prices can change, so farmers should confirm the current quotation before ordering.
Example Cost Calculation
If a farmer requires approximately 350 square metres of greenhouse film and the quoted price is Kshs 120 per square metre:
350 × Kshs 120 = Kshs 42,000
This is only an example. The actual quantity should be measured from the greenhouse design, including roof, side walls, end walls and allowances for fixing.
| Film Requirement | Example Price | Estimated Film Cost |
| 250 m² | Kshs 120/m² | Kshs 30,000 |
| 300 m² | Kshs 120/m² | Kshs 36,000 |
| 350 m² | Kshs 120/m² | Kshs 42,000 |
| 400 m² | Kshs 120/m² | Kshs 48,000 |
| 500 m² | Kshs 120/m² | Kshs 60,000 |
These figures are examples for budgeting and should not be treated as fixed market prices.
How to Choose the Right Greenhouse Polythene Sheet
- Thickness: 200 microns is a common commercial option.
- UV treatment: Important for longer outdoor service.
- Light transmission: Determines how much useful light enters.
- Light diffusion: Helps distribute light more evenly.
- Anti-drip treatment: Useful for condensation management.
- Film width: Should match the greenhouse design where possible.
- Expected lifespan: Ask the supplier for the manufacturer’s specification.
Installation and Maintenance of Greenhouse Film
The film should be stretched properly without excessive tension that could cause tearing. It should be securely fixed using appropriate lock channels and wiggle wire.
Farmers should also inspect the cover regularly for:
- Tears
- Loose sections
- Holes
- Dust accumulation
- Damaged locking systems
- Excessive condensation
Cleaning should be done carefully to avoid scratching or damaging the film.
Branches, sharp objects and poorly finished metal edges should also be kept away from the covering because they can cause punctures.