Home Posts Tagged "rose"


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Last Thursday, Aleia Roses introduced its premium label ‘Aleia’ at the Palacio Neptuno in Madrid. Following its introduction at the Royal FloraHolland Trade Fair in Aalsmeer, the time was ripe to introduce this rose variety in its Spanish homeland. Before an audience of 200 guests CEO Luis Corella explained the steps taken by the company until today, as well as the traits of this A1 quality ‘Red Naomi’ rose.

Aleia is the premium label of Aleia Roses for A1 quality Red Naomi roses with a bud size ranging from 5 to 5.5 cm. This spring, Aleia started marketing its A2 roses under the Reia label. The bud size of this rose variety ranges from 4.5 to 5 cm. According to Henk Lammers, Director of Logistics & Quality, the A1 roses have been cut since June and their share has now reached approximately 60%. “Our goal is for this to be raised to 80%.”

Teething pains

During the past six months, significant steps were taken to improve quality and grading, announced Lammers at the Trade Fair in Aalsmeer. “Proliferation has since been curbed, and the crop is basically stabilising. We no longer have any ‘cauliflowers’ (ed.: heavy buds with tree trunks). We have had to deal with multiple setbacks in the past six months: mildew, damage from the cold weather, and so forth. Still, I believe we came out very well. Additionally, our Bercomex Furora bunching machine is now operating as well as it should. It still needs some fine-tuning, but we have made significant steps since August. We are producing more homogeneous bunches, with the right grading, bud size, ripening stage and colour.”

Vase life

According to Lammers, the vase life is also perfectly in order: “This was proven by tests conducted at FlowerWatch, Royal FloraHolland and WUR in Bleiswijk. The vase life can reach up to 18 days, with an average of 13 days, following a transport simulation. We also regularly test the products of our fellow growers in the Netherlands and always come in among the top three. We also experienced a month in which our roses did not remain fresh as long, but this is something we have learned from. Vase life is of fundamental importance to us.” The roses are grown under assimilation lighting in winter, but not as intensively as in the Netherlands. Of course, the days are shorter in winter here as well. “As it stands today, we are one class above our fellow growers in the Netherlands. This is apparent from the positive response we received at the Trade Fair. I believe that we will really be able to make the difference in winter”, says Lammers.

Premium segment

With its new label, Aleia Roses is focusing on the premium segment, says CEO Luis Corella. How about the African rose? “We do not consider roses from Africa competition, as we focus on an entirely different segment. We are concentrating on top-notch quality and a long vase life. However, as a grower it is best to be in Europe, where you can make use of Dutch technology and know-how. Additionally, you must have control over the entire chain, to ensure that your product will reach your customer in the best possible condition.” The cultivation site in Soria was chosen with the utmost care, emphasises Corella, particularly because of the climate. The night temperature here never rises above 16 °C, not even in summer. The harvested product is shipped to the office in Aalsmeer by truck – cooled and on water – in approximately 19 hours.


Aside from the vase life, sustainability is another element of crucial importance to the Aleia label. This means: clean, safe and grown with a minimum of chemical crop protection agents and with sustainable energy, even if the fourteen-hectare high-tech rose nursery is still heated with gas. However, negotiations are reaching their final phase with a nearby biomass plant, where all the waste produced by the nursery is processed. It is Aleia’s intention to procure its heat and carbon dioxide from this biomass plant. “We collect and recycle rainwater. Additionally, we take our social responsibility seriously. We work with an organisation for the disabled, for example. It is important to us to create employment opportunities in a region where unemployment is relatively high.” At the Trade Fair Aleia Roses announced that it is now MPS-A certified.

Marketing plans

Aleia does not yet have any concrete plans for consumer marketing, although it is the company’s ultimate objective. Corella: “The consumption of roses in Spain is still rather low, and we would like to increase this. We are focusing on the luxury segment and wish to make the product more fashionable. Additionally, we want to reach the point where Spanish consumers ask specifically for Aleia within the next few years. In this respect, we also have a competitive edge on the Netherlands. However, we are now focusing on building up our brands in various commercial channels and delivering consistent quality and uniformity. If there is anything I have learned in the past year it is this: the market sets considerable demands and it costs a lot of time to gain confidence.”

Text: Mario Bentvelsen. Photos: Mario Bentvelsen/Aleia Roses.

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Energy is a major expense for rose growers. At Arend Roses, in the Dutch Maasland, research is being carried out into the effect of a customised light spectrum, through means of LEDs, on yield and the possibilities of it saving energy. The findings are encouraging but the energy efficiency of LEDs needs to be improved further to make the purchase of a second lighting installation profitable.

Research at Arend Roses took place in the winter of 2014-2015 and was initiated by operations director, Richard van der Lans. “For several years we toyed with the idea of introducing hybrid lighting to become more energy efficient, and hopefully have positive effects on yield and quality,” he says. “When I spoke to LED manufacturer Valoya, I had the feeling they understood exactly what I wanted to achieve. Since then we have carried out small-scale trials using prototypes of new LED-lamps which last winter culminated in a larger project involving several partners.”
These partners are Plant Dynamics and Wageningen University & Research Greenhouse Horticulture, which leads the research project. Both have a lot of experience with complex crop measurements. Initially the rose grower wanted to manage the research himself but without the input from the Dutch knowledge centres he wouldn’t have received financial support from the Kas als Energiebron (Greenhouse as Energy Source) program. “With hindsight I am very glad we did have their input, quite apart from the financing,” says Van der Lans. “Thanks to their knowledge and expertise we carried out very thorough research with very accurate measurements. We wouldn’t have been able to achieve the same level of sophistication and quality ourselves. In addition their input and involvement led to interesting discussions which substantially deepened my knowledge on the subject.”

Less energy

Van der Lans had calculated that by adjusting the growth light he could over time use 25% less electricity during the cultivation cycle. He calculated this, his initial goal, based on the hypothesis that a specific, energy efficient LED-lamp that could supplement the PAR-spectrum of the SON-T-lights – in combination with daylight – would enable the plants to better use the available light for photosynthesis and growth. Even at a low light intensity this should lead to a modest increase in yield.
“The 25% saving using this type of lamp, which provides a much broader spectrum than normal LEDs, is currently a bridge too far,” he says. “The positive effects on early growth and crop production that we saw in our previous trials were confirmed here but they were less large than we hoped for. When more efficient LED-lamps become available – and that is only a question of time – more energy can be saved and an additional LED installation can be profitable. That is not the case yet.”

Higher light efficiency

What exactly did this research yield? Project leader Nieves García Victoria, of Wageningen University & Research explains: “We compared three different growth light concepts over three repetitions and measured the effects on production and quality, photosynthesis and morphological characteristics such as colour, leaf surface area and leaf position.”
The growth light variations were the currently used SON-T-installation of 191 μmol PAR/m2.s as the reference and hybrid setups of respectively 103 μmol SON-T + 57 μmol LED and 103 μmol SON-T + 103 μmol LED.
“The hypothesis that supplementary LED-light results in higher production was confirmed for both variations,” says Van der Lans. “Also, we harvested fewer A2-quality.” Sander Pot, of Plant Dynamics, adds: “Under 206 μmol of mixed light, the light utilisation efficiency of the crop, expressed in grams production per mol light received, was 9% higher compared with SON-T only. Even under 160 µmol mixed light the light utilisation efficiency was 7% higher than under SON-T. Therefore the plant is better able to convert the mixed light into growth.”

No good explanation

Van der Lans and the researchers say that the positive effect of the mixed light was visible in the crop development within just a few weeks. “We saw the effects and of course wanted to know exactly how it was caused,” says Pot. “However, despite all the measurements we saw no clear morphological differences. Also the photosynthetic activity was almost the same and that is strange; we measured higher production but couldn’t put our finger on exactly how and why.”

Break-even point not yet reached

Now that the positive effect of hybrid lighting using broad spectrum LEDs has been established and the trial has ended, Van der Lans says it is now a case of waiting for further development of a light that offers the desired level of efficiency (see box). “In order to earn back the cost of a second installation within a reasonable period of time it needs to be more efficient than the prototype that Valoya developed for this project,” he says.
The break-even point has not yet been reached but hopefully that will happen within a few years. “The requirements for light emissions are stricter and it would be good if we can use fewer or less heavy SON-T-lights under the screen and supplement that with LEDs. Then the heat surplus, that is difficult to get rid of under a closed screen, would be less. And the energy bill would of course be lower which was the reason for starting the project in the first place.”

‘Better crop development with broader LED-spectrum’

The trials used a new type of LED-light, the Valoya G1. These emit light in a wider range of the PAR-spectrum than the monochrome red and blue LEDs that have been in use for some time.
“The advantage of these, especially the monochrome red LEDs, is their highly efficient use of energy,” explains Gonçalo Moreira Neves, of light manufacturer Valoya. “However, such lights have a very narrow spectrum. The plant can use it but it is too one-sided. If the light balance is disturbed too many morphological abnormalities and other undesirable side effects can occur, as independent research has shown on several occasions.”
To reduce this danger and to enable more efficient hybrid lighting comprising a larger proportion of LED-light, the Finnish company developed LEDs that supply a broad spectrum to fully support crop development. The G1 is the resulting prototype.

Efficiency 60% improved

A limitation of the new type of light is the significantly lower energy efficiency compared with the monochrome red LEDs. Meanwhile the company’s technicians are working on a follow-up. Currently we are achieving 60% higher light output of 1.8 μmol PAR-light/watt, but it has to be and can be even better,” says the spokesperson. “In the course of next year we hope to be able to offer a marketable version that combines the desired qualitative properties with the desired efficiency.”


A trial using a new type of LED-light with a broader spectrum confirmed that when this is used in combination with SON-T, production of roses is higher than when using SON-T-lights only. The energy efficiency needs to be improved further to make an investment in such hybrid lighting cost-effective. This would be beneficial in terms of energy and cultivation because such installations under a closed screen generate a lower heat surplus than SON-T-installations with a similar light output.

Text and images: Jan van Staalduinen

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Until recently, controlling aphids caused Christiaan Bot, production manager at Arend Roses in Maasland, a lot of headaches. Although he is familiar with biological methods, aphids were still treated with chemicals. However, the effectiveness of the chemicals was deteriorating rapidly, so Christiaan switched to the gall midge Aphidoletes, which turned out to be successful.

"Until two years ago, we used to spray against aphids about once a fortnight, but as time went on aphids reappeared more and more quickly. None of the chemicals currently permitted work well,” according to Christiaan. "In the past, I've tried to combat aphids biologically, sometimes using parasitic wasps (Aphidius). This worked well, but the problem with roses is that the aphid mummies were visible on the stem when the flowers were harvested. Although these mummies are entirely natural, it is perceived as a quality problem."


Marcel Verbeek, consultant at Biobest Netherlands, suggested to Christian that he should do a test with the Aphidoletes gall midge. This midge is a real predator, and leaves no mummies behind on stems. The experiment was successful. Marcel Verbeek says, "The trick is not just using the right natural predator; it is equally important to create the right conditions for this predator. It is crucial for Aphidoletes that it has the right environment to breed in."
Christiaan managed to create such an environment using buckets of moist coconut substrate, covered with old newspapers. This mimics the natural conditions which are necessary for adult mosquitoes to mate. They then go into the greenhouse looking for infestations of aphids.

Systematic approach

Aphidoletes is known for its excellent searching ability. With just 20 buckets, Christiaan managed highly effective aphid treatment on 4 hectares of roses. That translates to just 0.2 individuals per square meter, which seems very little, but enough to give excellent results.
With Aphidoletes destroying aphids, Arend Roses now has a new, highly effective addition to its biological control measures. Christiaan says, "We had already managed efficient biological control of whiteflies, spider mites and thrips, but this is the first time we have found an effective natural remedy for aphids. Now we really have found the missing link for an integrated biological systematic approach."

Source/photos: Biobest.

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Rose growers and propagators in Netherlands have been very badly affected by an outbreak of Ralstonia solanacearum. This Q-organism spread very quickly during last year’s hot summer. Fortunately strict hygiene measures have already been successful and recovery is in progress.

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In a large greenhouse with supplementary lighting the temperature differences in winter can rise so high it’s at the expense of quality and energy consumption. Berg Roses, of Delfgauw, the Netherlands, has already broken new ground with the Next Generation Growing and is fully committed to improving the climate. After a trial with vertical fans it is now running a trial with horizontal fans.

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Leo van den Harg, of the potted rose nursery in Vierpolders that bears his name, bought a Rombomatic ten years ago: a combination of four robots that takes cuttings from roses and subsequently roots them. ‘In the spring, we use it 7 days a week, 24 hours a day.’

What prompted you to buy this robot?

‘We were on the brink of an expansion, which would mean having to take as many as 400,000 cuttings a week for several weeks at a time. People can easily develop neck and shoulder complaints from this. Also: you can explain precisely to people how you want them to take certain cuttings, and root them, but people will always be people, if you know what I mean. If you use a robot you can be assured of a uniform quality.’

How long does it take for the investment of a robot to pay itself back?

‘Thanks to the robot I need fewer workers to take the cuttings and root them. Still, the reduction in personnel costs did not enable me to earn back my investment immediately. However, after a few expansions our investment in the Rombomatic was amply paid back. The Rombomatic also relieves my workers from heavy manual labour: all they have to do is put the cuttings in position. The only equipment they need to do this comfortably is a good chair.’

Does a robot always perform its duties?

‘Absolutely. In spring we use it 7 days a week, 24 hours a day. Three years ago we had four robots replaced. By that time we had rooted 125 million cuttings. That’s 125 million movements! We began to get an increasing number of malfunctions due to wear and tear. Of course, that wasn’t a huge problem: if one robot was out of operation, the other three can continue working. However, the capacity of the Rombomatic then drops to 80%. A big bonus was that the robots were replaced by new ones that work 10% faster.’

Do you use any other robots in addition to the ones that clip and root cuttings?

‘We make use of a packaging robot, but I wouldn’t really call that a genuine robot. That is more a question of automating repetitive movements. The same applies to the robots that pick up and move plants. Besides that, we don’t have any other duties here that could be performed by a robot.’

Text: Tuinbouwteksten.nl/Mario van Vliet. Photo: Mario Bentvelsen.

Download the complete dossier Robots in Greenhouse Horticulture (13 pages, pdf).

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Evaporation - and therefore energy loss - can be limited by removing excess foliage. This principle is, however, applied to only a few crop varieties. Professor Marcelis sees oppurtunities for sweet peppers, tomatoes, aubergines and roses.

‘Sweet peppers do not need their lower leaves for production, for example. These leaves do not contribute to photosynthesis, while they continue to evaporate moisture. Without this evaporation you could save energy. This is why you should remove the lower foliage in late summer or early autumn. Dutch growers, however, believe that this will take too much work. Their answer to the research proposal we submitted was "We’re not going to do that", because they did not expect it to yield any substantial profits. In cases like these there is no point in conducting a study to assess the production increase resulting from de-leafing, or whether or not de-leafing has a beneficial effect on susceptibility to disease due to the improved air circulation around the plant. Aubergines are another crop that would benefit from de-leafing in late summer or early autumn.

‘De-leafing sweet peppers is relatively easy: you simply tear the leaves off. You can easily estimate the results achieved in a calculation model. However, due to the immediate rejection by the horticulture industry this study was never given a chance to prove the benefits of de-leafing.

‘Tomato growers, on the other hand, have embraced de-leafing as a useful practice. Research is now being conducted into the amount of foliage that is genuinely needed by a plant. Plants produce too much foliage in winter, in any case. We are conducting in-depth research into this.

‘When growing tomatoes, you remove the leaf at the head of the plant before it has fully formed. The plant will then no longer need to spend any energy on the development of that leaf. This is already being done in practice, but the process could be improved. Research is currently being conducted on this by Wageningen UR Greenhouse Horticulture in Bleiswijk, but I am not directly involved in this project.

‘We have not yet reached any definite conclusions with regard to how much foliage is desirable. I am convinced that de-leafing would also be useful in the cultivation of roses. Roses waste a lot of energy on unnecessary foliage. If all the sugars now seeping into bent branches would be made available for production, you could probably harvest many more branches. We have to come up with a smart solution for that. I am certain that far too much energy is being lost.’

The emergence of LEDs, climate control and a growing insight into plant physiology allow crops to be grown in greenhouses all over the world. Does greenhouse horticulture in the Netherlands have a future?

‘There are actually many advantages to greenhouse horticulture in the Netherlands. Summers aren’t so hot. There could be more light in winter, but there are other greenhouse horticulture areas - such as in the United States - where winters are much colder. Many regions have to cope with regularly extreme weather conditions. No, greenhouse horticulture certainly has enough advantages.

‘It is, however, a fact that horticultural developments are taking place at an accelerated pace all over the world. The Netherlands is a front-runner with respect to efficiency. If you wish to retain that leading edge you will, however, have to continually come up with smarter solutions with regard to efficient cultivation, marketing, quality and vitamin and nutrient content. Innovation is essential to horticulture.’

Leo F.M. Marcelis (Elst Gld, 1963) studied horticulture at Wageningen University, where he obtained his PhD in 1994. He was a professor by special appointment of Crop Production in Low-Energy Greenhouses at Wageningen University until 2013 and team leader at Wageningen UR Greenhouse Horticulture. On 1 December 2013 Prof. Dr Leo Marcelis was appointed Professor of Horticulture and Product Physiology at Wageningen University.

Download the complete interview with prof. dr. ir. Leo Marcelis about diffuse glass, LED-lighting, urban farming, de-leafing and the effects on plants, energy consumption and cultivation strategy (login required).

Source/photo: Tuinbouwteksten.nl/Theo Brakeboer.