Greenhouse Film's Light Transmittance on Plants and Measurement

1. The necessity of measuring the light transmittance of greenhouse films with a light transmittance meter

Plastic film has good thermal insulation properties, when crops are covered with plastic film. The temperature inside the greenhouse film will rise. And as the temperature difference between day and night changes, the external temperature difference becomes larger and the temperature difference within the film becomes smaller. When the temperature in the sunlight shed increases during the day, the turbidity also increases with the temperature. The new greenhouse film is generally tested with a light transmittance meter for a light transmittance of 80% -90%. But during use, the greenhouse film will absorb water droplets, dust and aging, which will affect the transmittance of the greenhouse film. We know that plants generally promote growth through photosynthesis. Therefore, the light transmittance of the greenhouse film is a key factor affecting plant growth. It is necessary to measure the light transmittance of the film with a light transmittance meter.

2. How to increase the light transmittance of greenhouse film?

(1) Regular cleaning

Every one week or so, clean the surface of the greenhouse film with clean water, wash off the dust, dust, broken grass and floating objects on the surface. After cleaning the greenhouse film, the light transmittance can be increased by (5-8)%.

(2) Regularly turn the film over

Greenhouse film is generally used in autumn and winter. We can fasten the film for 15-20 days before and after the frost. Choose a sunny and windless day to remove the film. Keep the original side facing down and then secure it. This will reduce the water droplets and increase the light transmittance of the agricultural film.

(3) Spray the film with soy flour

Grind the soybean into a fine powder and soak it in water for 150 hours (approximately 7.5-10g of soybean powder per square meter of greenhouse film) and then filter with fine gauze. After removing the residue, use a sprayer to spray the water droplets on the greenhouse film, and the water droplets can quickly fall. And no new water drops will regenerate in 15-20 days.

(4) Wipe gypsum powder or dry fine soil

Spread the new agricultural film on top, sprinkle with fine soil or gypsum powder, and wipe it with a towel or cloth repeatedly several times before cleaning. Cover the film with the treated side facing inwards, which can significantly reduce the adhesion of water droplets in future use.

3. Use the light transmittance meter to detect the light transmittance of the greenhouse film

The light transmittance of the greenhouse film is so important. So how do we detect the light transmittance? Although the naked eye can roughly see the light transmittance of the greenhouse film, it cannot accurately give the specific light transmittance value. Therefore, it is recommended to use a professional light transmittance meter for the detection of light transmittance. Linshang LS116 transmittance meter is specially used to detect the transmittance value of transparent materials. The instrument uses a parallel light path design, which can also detect the light transmittance of large thickness materials, ensuring that the LS116 light transmittance meter can pass the inspection of the National Metrology Agency.

The heat in sunlight mainly comes from infrared rays and blue-violet light helps the growth of crops. So there will be some eco-film products on the market. So what is the quality of eco-film products? Linshang Technology has instruments that can measure the transmittance of infrared and blue-violet light. Users can choose according to their needs. For details, please consult our engineer at sales21@linshangtech.com!