Coating options for sweet peppers

Sweet peppers love light, but peaks in light levels can lead to stress and growth disorders. A coating that makes the light diffuse, results in steady continuous growth and yield.

Pepper growers are increasingly using coatings on the greenhouse roof, mainly due to the development of different types of coatings. The prevention of heat stress has traditionally been their main motivation. Also a balance needs to be found between allowing in as much light as possible, preventing the greenhouse climate becoming too dry and warm and an excessively high plant temperature.

Over time, an additional requirement has arisen. It is now clear that diffuse light offers large benefits. Diffuse light penetrates deeper into the crop than direct radiation. As a result many older leaves can also contribute to photosynthesis. It is true that the upper leaves photosynthesize slightly less but this effect is relatively small so the net result is more photosynthesis throughout the entire crop.

Diffuse
The extent to which a coating makes the light diffuse is expressed by the haze factor. The higher the haze factor, the more the light is scattered. Research on fruit vegetables has shown that diffuse light leads to better results. In practise, peppers growers see less blossom end rot as well as heavier and better shaped fruits under a diffuse coating.

TransPAR has a very high haze factor (up to 86%) and so offers optimal light diffusion with good heat resistance. The concentration at which TransPAR is used for peppers in the Netherlands means the haze factor is somewhat lower, but still higher than other products in this segment.

An alternative product that is increasingly being used is Optifuse IR. This hardwearing coating combines the same high haze factor with higher light transmittance, which is good for photosynthesis. At the same time Optifuse IR, like TransPAR, reflects infrared light, which is for a large part responsible for heating the plant. Because the plant doesn’t use infrared light for photosynthesis, it can be shaded out without any drawbacks. Compared to TransPAR, Optifuse IR offers slightly less heat resistance, more diffusion and higher light transmission.

Applying a coating reduces the need to use the movable screen in summer to almost zero. The coating that is most suitable for the greenhouse situation depends on the type and manner of cultivation.

For more information:
Sudlac
Jorien Plak-Schouten
export@sudlac.com
www.sudlac.com
+31 (0)6-42736969