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Greenhouse shading screens are cloths/screens, which are placed just under the greenhouse’s gutter. Generally, cloths are folded when used. However the screens can be closed mechanically anytime. By means of a shading screen, the cultivation can be adjusted easily.

Many different types of shading screens can be found, each with their own function. The most prominent functions are listed below:

1. Saving energy
Warmth is needed by the majority of the plants. Sometimes enough sun is present for the greenhouse to warm up. However, in the night or on cold days, the greenhouse should be warmed by the cultivator through a kettle or an cogeneration installation. In order to prevent the disappearance of warmth from the greenhouse, shading screens are applied. In this case, the screen is used as a blanket to maintain the warmth. The only disadvantage that can be named, is that shading screens reflect the (growth) light. The criterion that the saving of energy should be higher than the costs of ‘growth-loss’, is set for shading screens.

2. Blocking sunlight
The irradiance of the sun is determined by the shading screen, once the light level is too high. Especially on summer days, damage to the crop (burning) can be caused by a high level of irradiance. Shading screens are used for protection. Shading screens are supplied in different shading percentages, in order to make sure there are several options.

3. Obscuration of light
The excess amount of light is blocked by a shading screen. Different colors are used for a shading screen: black for the bottom and white for the top. Plants and flowers, such as chrysanthemums and kalanchoe, are believed to profit from these different colors. This because specific ‘day- and night-lengths’ are needed in order for the plants to flower. The correct day and night rhythm can be achieved by means of assimilation lights and shading screens. The advantage is that the plants can be cultivated at any time of the year.

4. Limit the loss of light
Screens that are used to limit the loss of light, are opposite to the shading screens that block irradiance from outside. The shading screens that are used to prevent the light from ‘leaving the greenhouse’ are used by companies that utilize assimilation lightening. Through this screen, the loss of light is limited, resulting in the minimization of disturbance of the direct environment of the greenhouse. When these screens are used, they are fully closed. An advantage, is that in the ‘dark hours’ the screens lead to an energy saving of up to 25%.

5. Spread diffuse light
Moreover, light can be diffused with the help of a shading screen. Often, this function is combined with the sun blocking function of the screen. Due to diffused light, light on every part of the crop is ensured (also the parts that are harder to reach). Moreover, burning of the crop is prevented by diffusing the light. 

Mostly horizontal shading screens are used in greenhouses. These screens meet the basic need, which is blocking the sun and/or creating shadow. Horizontal shading screens are installed just beneath the greenhouse’s roof. Besides the horizontal screens, vertical screens are available. These are also called “facade screens” and hang against the walls/sides of the greenhouse. The vertical shading screens are mainly used to create compartments in the greenhouse.

Horizontal shading screens are placed directly under the greenhouse’s roof and are known for covering a large surface. When arranging and monitoring the climate within a greenhouse, shading screens are an important component. Besides, energy saving can be achieved by means of a horizontal shading screen. Often a screen as such has a double layer, making it easier to arrange the amount of shadow and light in the greenhouse. Generally, a shading screen is more flexible in use than shading agents. When the weather suddenly changes, the climate within a greenhouse is easier to adjust when making use of a shading screen. Unlike shading agents, that will hold on to the greenhouse’s walls up to three months and are not easy to remove and re-apply quickly when needed. 

Vertical shading screens, in other words facade screens, hang against the walls/sides of the greenhouse. These screens cover a smaller surface of the greenhouse, since they are solely targeted at the greenhouse’s walls/sides. 

Just like horizontal screens, vertical shading screens arrange the climate within the greenhouse. Another similarity of the two types of screens, is the fact that they keep the light inside of the greenhouse and/or have an energy saving function for the cultivator. The thing that differs the two types of shading screens, is the possibility for the creation of compartments within the greenhouse, which is only possible with a vertical shading screen. The screens that make this division possible are also called “twin roll facades” or “twin roll walls”. When different crops are placed besides each other and demand a different amount of light or temperature, vertical shading screens come in handy. It is important to know that the use of a horizontal screen does not exclude the use of vertical screens. It should be seen as a cooperation between the two types of screens. 

The installation of a shading screen is believed to be work for an expert. Especially when an entirely new system has to be installed. Generally, the assembly of a new screen to an existing system is done. Here, the old screen is removed before the new screen can be placed.
Basically, not much maintenance is asked by a shading screen. However, after some years, a worsened transparency can be the result of dirt piling up on the screen. The loss of transparency can be prevented as much as possible by cleaning the screen regularly. For this, Menno Hortisept clean PLUS is often used.

Attention: Cleaning must be done very carefully, since these screens are fragile.

At first, a shading screen and a shading agent seem the same. This is partially true. Because there are some differences: 

Short vs. long term investment
The largest difference that can be named is the lifespan of the products. A screen can be used for several years, whilst a shading agent is only temporary. 

Energy collection vs. energy loss
Saving energy is the most important function of a shading screen. When the warmth is kept inside, energy loss is prevented. The function of a shading agent can be seen as the complete opposite, namely to prevent sun coming into the greenhouse. This is done by the reflection of the sun’s irradiance, resulting in maintaining a constant temperature within the greenhouse. This actually means, the two different options cannot be replaced by one another. An optimal climate can be realized through a combination of these two products. 

Spread diffusely with and without difference in temperature
The choice for the diffusion of light is often made on warm summer days. Burning of the crop can be prevented, and a deeper reach of light into the crop is ensured. Shading agents like D-Fuse or D-Fuse Extra can be used for diffuse light, without experiencing any problems of the greenhouse’s temperature rising. A rise in temperature can be caused by making use of a shading screen, since it has an isolation function. 

Even though it is often thought that these two options can replace one another, we know this is not the case. Shading screens and shading agents serve the same purpose, however do this differently. So, the products are not substitutes. They can better be combined to achieve a perfect climate within the greenhouse.

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