Shade under anti hail nets, woven film, tunnel film, insect mesh and shade nets.

A common question we get is about how much shading there is under different systems. Shading can be advantageous in many crops, but also disadvantages. In this blog, I want to give you a clear overview of the differences in light transmission with our products.

Several studies have been done on hail nets and shade, we share here the information we think are most accurate for our nets and foils.

Anti hail nets and shade

I'll start with anti hail nets. FruitSecurity Holland supplies many different colours of hail nets.

1. Crystal anti hail net
2. Black anti hail net
3. Grey anti hail net

FruitSecurity also supplies other colours such as light grey or white, but since the difference between those colours is not that big (compared to standard nets), in this blog I will only cover the most common colours.

Crystal anti hail net

Crystal hail net has a shade of 8%. Crystal hail net is the most common hail net in northern Europe. Is the sun intensity not extreme in your area? Then 8% is just enough to prevent sunburn and have the height efficiency under your fruit protection system.

Video: Bangels on his experience with hail nets and sunburn.

Black anti hail net

Black hail netting has a shade of 18%. This net absorbs a lot of light and is therefore suitable for areas of high sunlight. Check out a very interesting study on (black) hail nets in coastal regions here (dutch only).

Video: black hail nets

Grey anti hail net

Grey hail nets block slightly more sunlight than crystal nets. Grey hail netting has 13% shade.

Summary

As you know as a grower: every % more or less light affects cultivation. Increasingly, less light is beneficial. In hot years with lots of sun, it can help immensely against sunburn. Sunburn can destroy a lot, and that can be prevented by hail nets.

But if there are years with very little light, hail nets with a lot of shade can be a disadvantage.

Shade and woven film

PC-Fruit included light loss in its research on protection systems. Here is a summary:

A number of light measurements are carried out every year. For these, the amount of PAR light is measured. The average light loss during these periods is shown in table 1.

Table 1: Average light loss for each system over an extended measurement period.

Object	2012	2013	2014	2015	2016	2017	2018	2019	2020
Powerflex (2016)	-	-	-	-	29%	36%	32%	-	39%

Table 2: Difference in light loss between a sunny and a dark day.

	2018	2018	2019	2019	2020	2020
	sunny day	dark day	sunny day	dark day	sunny day	dark day
Powerflex (2016)	28%	30%	-	-	43%	28%

Figures 1 and 2 show a comparison of available sunlight between the control and Fruit Security rain protection system during a high-light and low-light day.

Summary woven film and shade

The percentage light loss in 2020 was 39%, in 2019 no light measurements were made at this protection system, but in 2018 the percentage light loss was 32%. In 2020, the difference in light loss between sunny (43%) and cloudy days (28%) increased compared to 2018.

Woven foil has increasing light loss the older the foil gets. This is because more and more dirt sticks to the film.

Curious about the rest of the study? View here.

Tunnel film

Tunnel film is tunnel film right? Nothing could be further from the truth!

Every tunnel film is different, though there are some foils that are very similar. All types of foil are divided into these 2 standards:

1. Clear tunnel film
   Diffuse tunnel film

Like woven film and anti hail nets, tunnel film is not just about shading. For the highest efficiency under your tunnel films, you need the right combination of transmission (how much light the foil lets through) and diffusion (how much light is diffused).
Because FruitSecurity has many different types of foil, I want to take you through the standard types. Curious about the other types? Or if you have specific requirements, contact us and we will be happy to help!

Clear tunnel film

Clear tunnel film is often used as a double wall in a foil greenhouse, or for bringing forward a crop. Clear foil is clear, so it lets a lot of light through.

Often its transmission is around 90%. And diffusion about 25%. So the light shines brightly and directly on the crop. The main disadvantage of clear foil is that the light is not distributed well to the plants.

Diffuse tunnel film

Diffusion foil is used year-round for all kinds of fruits and vegetables. Transmission is around 87-89%, and diffusion around 55%. So a lot of light still enters the tunnel, and it is distributed nicely to the plants.

Summary shade and tunnel film

Every type of tunnel film is different. In our catalogue you can see the types suitable for the Netherlands and neighbouring countries. A lot can be experimented with tunnel film, and a lot can be gained with the right foil.

Read a more detailed explanation of lighting effects and tunnel film here.

Read about sunburn and tunnel foil here.

Insect mesh

Insect mesh are often installed on sides and in the gutter of rain protection systems. As a result, the insect mesh will not have the greatest impact on the crop. FruitSecurity Holland supplies 2 colours of insect mesh, with a mesh size of 40 mesh.

1. White insect nets
2. Black insect nets

White insect mesh

White insect nets or insect mesh has a 20% shade reduction.

Black insect mesh

Black insect net or insect mesh has 50% shade.

Conclusion insect mesh

Many growers choose black insect nets on the side of their plots because it is easier to see through black insect nets. In the gutter, however, white insect mesh is recommended because of light loss.

Shade nets

Shade nets are available in many different types and colours. FruitSecurity often supplies shade nets with a shade of 25%, 50% or 75%.

I hope I have given you a good idea about shading under different foils and nets. Like you, we like honesty and accurate information. Do you still have a question or comment about anything? We would love to hear from you!

Also take a look at the following resources:

• Light and sunshine - Tunnel film
• Prevent sunburn - Tunnel film
• Optimising light utilisation - Anit Hail nets (Dutch only)
• Report hail nets - Anti Hail nets (Dutch only)
• Temperature PowerFlex - Rain protection systems

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Wilbert Hendriksen Productspecialist fruitprotection My mission and duty is to help as many fruit growers as possible get a good harvest. So that fruit damage can be prevented, no delivery problems occur and that fruit growers can harvest successfully!