Home Posts Tagged "Ludvig Svensson"

Ludvig Svensson

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There are around one million hectares of greenhouses in China. Many of these are so-called ‘’Solar Greenhouses’: greenhouses with a wall that stores solar radiation during the day and releases it into the greenhouse at night.

We recently built a similar style greenhouse at our Bleiswijk site. Together with our consortium partners Delphy, Ridder/Hortimax, Hoogendoorn and Svensson, we kitted it out with a number of Dutch technologies. Of these, substrate cultivation with an irrigation computer, automated ventilation and a transparent screen inside the greenhouse are the most eye-catching innovations. With this Dutch technology and expertise we are aiming to achieve higher production with fewer problems with diseases.
We started off growing cucumbers. On 30 March we planted two varieties: a well-known, robust “Dutch” variety and a new “Chinese” variety with smaller, spiny fruits. The plants are being grown on a semi-high wire system. The crop got off to a promising start straight away due to the flexibility of the screen.

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Recently, harvesting of cucumbers started in the new Winter Light Greenhouse at the Greenhouse Horticultural Department of Wageningen University and Research Centre in Bleiswijk.

The High-Power (Nunhems/Bayer) cucumber variety was planted on 19 September. Thanks to the good weather, the crop matured rapidly in this light greenhouse, so the first examples could already be harvested on 11 October. These first fruits were remarkably long; at the start of the harvest, fruits tend to be short. The growers who visited this test site every two weeks noticed that the plants were strong, with good ovaries and large leaves at the base. Although the greenhouse transmits more than 10% extra light in comparison with a standard greenhouse, light is still a limiting factor in this period. With the acquired knowledge, a second crop was planted immediately after Christmas.

Greenhouse concept

The Winter Light Greenhouse is a new greenhouse concept which, in combination with a new type of screen system, new screen cloth and light-diffusing glass, improves light transmission by more than 10%. The entire newly-designed greenhouse structure is provided with a white powder coating, which offers an increased reflection factor of 90%. The greenhouse is glazed with SmartGlass, a new type of diffusion glass with large panels. Even if the glass is wet or covered in condensation, light transmission remains constant. The integrated Iso++ screen system is mounted in a W-shape for optimal light transmission when the screen is closed, and features a new Ludvig Svensson screen with even better light transmission. The new greenhouse design is also fitted with an Air in Control climate system.

The Winter Light Greenhouse was developed by a consortium of BOM Group, Ludvig Svensson, Bayer Crop Science and Glascom Tuinbouw, in collaboration with Wageningen UR. The project was also assisted by the Greenhouse as Energy Source (Kas als Energiebron) programme, LTO Glaskracht’s innovation and action programme, and the Dutch Ministry of Economic Affairs.

Source/Photos: BOM Group.

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Gerbera grower Batist, of Maasdijk, the Netherlands, fitted a new, moveable climate screen with improved light diffusing properties into one of its greenhouses this spring. Due to less direct radiation, the crop is less quickly exposed to stress and ultimately on sunny days more light can be allowed to enter the greenhouse. The combination of better light distribution and less shadow results in a more generative crop that yields more.

Thanks to the new screen installed by Ruud Batist this spring, he no longer needs to whitewash the greenhouse. He was quite pleased with the diffuse coating that he applied each spring but the permanent layer of chalk also blocked out light and heat when it was not necessary. In addition the radiation entering through open windows was sometimes too high in places, causing sensitive varieties to visibly suffer.

Perform better

“I knew it could be better,” says the mini gerbera grower. “Therefore last year at another location we installed a Harmony screen with a shading percentage of 35 per cent, which also has light diffusing properties. This meant I could be more responsive to the circumstances. This spring we installed a variant on the further developed New Harmony line in an entire greenhouse. I am convinced that this will perform even better.”

More generative

Although Batist can’t make an objective comparison between the new screen, the classical type and the diffuse coating that he previously used, he says he is very satisfied with its performance. “The new fabric lets more light through and we have a more generative crop. Several colleagues within our growers’ organisation, Colours of Nature, work with the classic screens and we regularly meet in the greenhouse. They agree with us."
The difference in generative growth is so large that the gerbera grower is at odds with the usual day length regimes. “Normally, under cooler, fertile growing conditions, such as those we experienced up to mid July, you need to maintain shorter days to keep the crop in a sufficiently generative state,” he says. “However, this screen lets through so much light without passing the critical value of 1,000 μmol, that the plants receive a generative boost.”
Batist can reduce the hours of darkness and the resulting higher light sum is, as a rule, converted into extra growth. “Many of my colleagues start to darken the greenhouse around 1 July but we can maintain a longer day. It can only translate into higher productivity.”

Further developed

Paul Arkesteijn, of Svensson, nods affirmingly. “The first generation of Harmony screens was introduced eight years ago and developments have been ongoing," he says. “At the time it was the first moveable climate screen with diffuse properties. The big difference with previous fabrics was that the usual aluminium strips in the open, knitted cloth were replaced with white plastic strips."
According to Arkesteijn these screens allow more light through which is subsequently distributed wider. By varying the number of white strips in the cloth, gerbera growers can chose a screen that shades out 25, 35 or 45% of the light.
“Three years ago we picked up the thread again,” says Arkesteijn. “In the meantime, a lot of new, independent research had been carried out into the effects of diffuse light in crops. Based on that we wanted to research which aspects of our screens could be further improved. Growers are always raising the bar higher, both for themselves and for their suppliers. Our R&D department tested several new materials and the result of that exercise is the new series.”
According to the screen specialist the diffuse property of the fabric has above all improved in the screens with a lower shading level. “That makes these versions very interesting for gerbera and rose growers for example,” he adds. “The 25 and 35 per cent versions of Classic Harmony are already used a lot in these crops. We know that when the radiation is more than 1,000 μmol PAR a gerbera crop can experience stress. Measurements show that in Batist’s greenhouse, the light level remains well below this figure under the new screen. It has a shading percentage of 23 per cent.”

Less stress, more light

Better diffusion offers several advantages. Firstly you can allow more light to enter the greenhouse before the crop suffers stress from the high direct radiation. Secondly, better light distribution reduces the amount of shadow from greenhouse parts such as gutters, columns, air mechanisms and (trellis) rafters.
Arkesteijn: “The results of a trial under practical circumstances show that under the new climate screen, the crop in the shadow receives 32 per cent more light than under the first generation screens. The sunlight is more evenly spread over all plants and all parts of the plant. The result is a more uniform and faster growing crop.”

Another step further

Batist notes that the new climate screen offers him even more opportunities to optimise the growth factor, light. “The plant balance and bud formation are influenced by many factors,” he says. “You have to use screens during the lighter months to protect the crop from excessive radiation. Whitewash offers protection but also prevents light entering when it’s not necessary. In this respect the classic screen was a clear improvement. This new screen goes a step further and enables even more light to be converted into growth and production.”


The grower says that he hasn’t been using the diffuse climate screen for long enough to confirm his high expectations with hard figures but he expects to have them within a few months. “When comparing nurseries or different locations with varying systems and varieties even within one company you need to be careful,” he says “However, I’d be surprised if over the long term this greenhouse doesn’t stick out above the rest.”
Paul Arkesteijn also believes this new screen will be an asset to gerbera growers, among others, even though it wasn’t tested on gerberas during the development phase. “We can’t attach any crop related figures. However, we know the transmission properties inside-out and they are excellent. They are the result of three years intensive research."


A new type of climate screen with improved diffuse properties makes it possible to admit higher light levels during gerbera cultivation. This produces a generative crop response. The reduced shadow from light intercepting greenhouse parts and equipment also results in more uniform growth. On balance, this should lead to higher production.

Text and images: Jan van Staalduinen

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On Thursday 16 June Svensson and Hoogendoorn accepted the GreenTech Community Award 2016 for their mutual innovation 'Connected Screening'. The software module casted most public votes.

Hoogendoorn and Svensson introduced 'Connected Screening' during the GreenTech in Amsterdam. The software module calculates the effect of various screens on ventilation, humidity transfer, energy savings and transmission of light and outgoing long wave radiation based on the Svensson screen characteristics and position. With this accurate data growers can achieve more screening hours without risking high humidity levels below fully closed screens. This allows growers to achieve a homogeneous climate, higher crop yields and up to 20% extra energy savings. Data is presented at a glance via a custom-made visualization.

Next Generation Growing

Field research within the Next Generation Growing (NGG) shows that the highest crop yields are achieved under double layer energy screens and completely closed screens (without gaps). However, in practice this is often hard to realize due to a mismatch of screen characteristics or inefficient use of climate control. This leads to an unstable greenhouse climate. The consequence: an increase in pests and diseases that negatively affects crop quality and yields. Hoogendoorn Growth Management and Svensson respond to these needs with the new screening software Connected Screening, specifically developed for the iSii process computer.

In the weeks before the GreenTech the public had the opportunity to cast their vote for their favorite innovation (out of 73 entries). 'Connected Screening' received 46% of the votes, followed by Priva's deleafing robot (36% of the votes) and HortiMax Go! of Ridder HortiMax (9% of the votes).

Source: Hoogendoorn/Svensson. Photo: GreenTech.

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BOM Group will present a completely new greenhouse concept at the Greentech: the Winterlight Greenhouse. This concept, in combination with a new type of screen system by Svensson and light-diffusing glass, yields 10% more light.

The Winterlight Greenhouse, with all its installations, systems and products is currently built on the site of Wageningen UR Greenhouse Horticulture in Bleiswijk and will measure 500 m2. This coming winter the greenhouse concept will be tested with a new cultivation method for a cucumber crop, focusing on the winter period. Crop trials are conducted with the cucumber variety Hi-Jack. This variety is especially suitable for winter cultivation because of its leaf shape and direction.

Reflection factor

The newly designed greenhouse structure is fully powder coated in white with an increased reflection factor of 90%. The greenhouse is glazed with SmartGlass, a new type of diffuse glass, sized 300 x 167 cm. Even if the glass is wet or condensed, the light transmittance does not decrease. The integrated Iso++ screen system is installed in a W-shape for optimal light transmission in closed position and is equipped with a new high transparent screen fabric of Ludvig Svensson with an even better light transmission. The new greenhouse concept is also equipped with an Air in Control climate system (overpressure air).


The Winterlight Greenhouse was developed in collaboration with Wageningen UR, Svensson, Bayer Crop Science and Glascom Horticulture. The project has been made possible by the program Kas als Energiebron, the innovation and action program of LTO Glaskracht and the Ministry of Economic Affairs.

BOM Group will present the new greenhouse concept at the GreenTech, hall 8, stand 108.

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Van Uffelen Flowers held an open-doors day to show off its newly delivered four-hectare chrysanthemum greenhouse at Herenwerf in Maasland on Saturday 16 April, together with its builders and installers.

The newly designed Greenhouse was built by Technokas. The greenhouse cover was executed in diffuse glass, with a haze factor of 70. Another interesting detail is the double screening system by Svensson (Harmony 2515) and Bonar (energy-saving blackout cloth), executed by Huisman Scherming. The lighting system was provided by Hortilux Schréder (1,000 Watt SON-T narrow-angle lighting fixtures, 10,000 lux), and the other water and electrical systems were by Stolze.

Next Generation Cultivation

The greenhouse is prepared for the installation of air handling units for mixing the air in the greenhouse with air blown in from outside, in accordance with the basic principles of Next Generation Cultivation. ‘This system allows the entire air content of a greenhouse to be complete renewed approximately once every hour,’ explains Hans van Tilborgh of Technokas. ‘It will not be replacing the air vents, but will comprise a useful addition to them.’ Before the outside air is blown into the greenhouse through a large hose, it is heated to the greenhouse temperature. This is to prevent climate differences in the greenhouse.

However, the system does not provide in heat recovery, like tomato grower Ted Duijvesteijn’s ID Greenhouse. ‘That would mean installing a much more complex system. It also saves energy. In combination with a double screen this greenhouse will allow us to save 30 to 40 per cent more energy than in a conventional chrysanthemum greenhouse,’ continues Van Tilborgh.

Production halls

In addition to the greenhouse, Technokas also supplied Van Uffelen Flowers with hoistable heating frames and production halls, designed by the Poortinga & Zwinkels architecture firm. According to architect Hester Poortinga, Van Uffelen aims to have its new building reflect the brand identity and values of Zentoo: transparent, unifying and innovative. Zentoo is the trademark under which Van Uffelen chrysanthemums are marketed. The chrysanthemum varieties are supplied by Fides and Deliflor.

Other technical tours de force at Van Uffelen Flowers are the Robur fully automated spray boom, the ISO Group peat block planting machine and the Bercomex harvester. Once harvested, the flowers are transported to the shed on underground conveyor belts. The cooling facilities with pre-cooling units were supplied by Hamelink Koeling BV.

Text/photos: Mario Bentvelsen.