Home Posts Tagged "lettuce"


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The restaurant at the High Tech Campus, Eindhoven, the Netherlands, serves various types of lettuce that have never previously seen the light of day. They are crispy and tasty and are a good match for any greenhouse lettuce. One hundred metres further up the road, researcher Stefan van de Voort is growing the lettuce and herbs in fully enclosed climate cells. They are produced under LED lighting at the new research facilities set up in this town that has become synonymous with lighting.

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During the 'Vertical Farming, in or out?’ meeting on 14 October 2016, Rien Panneman of Staay Food Group announced that the company would be producing its own lettuce in a large vertical farm in Dronten from 2017. The new building is expected to be ready in mid-April 2017. The farm will be up and running by June 2017, according to Panneman. The meeting was organised by InnovationQuarter.

During his presentation, Panneman outlined why Staay Food Group has taken on a vertical farm project. "We have a factory in Dronten where we produce sliced vegetables and salads. The desire arose for more certainty, especially in the area of food safety. Another reason is local-for-local. At the moment, we source our lettuce for six months of the year from the Netherlands, and the other six months from Spain or Italy, so it’s not as fresh as it could be. If we can produce that in-house in the same place where we process it, we can guarantee sustainability thanks to lower logistical costs and reduced CO2 emissions. There are also other benefits, because there will be fewer foreign materials such as rocks, insects and even, in exceptional cases, frogs."

Clean product

"The retail market at home and abroad stresses that we must concern ourselves with a cultivation method which is completely in line with vertical farming," continues Panneman. “There are various benefits to vertical farming; lower energy consumption and water consumption, for example. We also see advantages in terms of plant protection and microbiology. Supermarkets are trying to distinguish themselves by setting maximum limits for pesticide residues. However, that is obviously not the only battle. We have done tests with Philips, and found that products grown under LED lighting are many times better than products grown in the open soil in bacteriological terms."
Continuity also plays a role. “With vertical farming, we obviously know exactly when to sow and when to harvest, and the quality to expect," said Panneman.


In addition to the demand from supermarkets, the cooperation with lettuce grower Deliscious and developments in Japan have inspired investments in vertical farming, as Panneman explains, "Consumer prices in Japan are much higher than here, enough to make it viable there, in contrast to the Netherlands. We contacted a number of partners for discussions; Philips, Rijk Zwaan, HAS Wageningen, CAH Vilentum University of Applied Sciences in Dronten, and development company Flevoland. We sat down with them round the table, and explained that we want to set up something unique in Dronten. We are now working hard on it. A completely new factory is being built, scheduled for completion in March/April 2017. The vertical farm area is now being engineered, and is expected to be operational in June."


Staay Food Group’s new Fresh-Care Convenience Centre covers a total of 27,000 m² of floor space. The main area consists of high-care and low-care rooms. The entire hall in which the vegetables will be cut and packaged will be cooled. This includes the vertical farm, a conditioned space where lettuce is grown hydroponically under LED lighting without daylight. A 70,000 m2 plot is available next to the factory, where phase 2 can be built. Panneman, “We will be rolling out phase two as soon as we feel confident about growing under LEDs, guaranteed costs, and quality levels."
However, the ambition goes beyond the creation of a state-of-the-art production facility. "The new building is also an auditorium, where lessons can be given. We will also train foreign students. That gives us, and our partners, an advantage of course."

Income model

The cost of growing prime lettuces in a vertical farm is currently double that of current methods of cultivation. "However, the advantages are obvious and this is something our customers, the supermarket chains, recognise," says Panneman. "In addition, the cost of the lettuce component is limited, so our customers will gladly accept a limited price increase. After all, they receive a higher quality, safe and sustainable product for their money, with which they can distinguish themselves from the competition."
Staay Food Group is already thinking about setting up vertical farming projects outside the Netherlands. Panneman says, "You see more and more local-for-local and region-for-region agriculture, which means that we will eventually lose a lot of our export markets in the future. I think we should respond positively. We have to maintain our knowledge advantage in the field of fresh food production, and create a new model for generating income. State Secretary Van Dam recently said, ‘Let's stop dragging commodities around, and focus on exporting chain and production knowledge.’”
Staay Food Group is willing to share new knowledge. “Ultimately, we will also benefit from this; we need people who know how to grow under LEDs, who we can put to work both in the Netherlands and beyond." To conclude, he says, "We are convinced that this will be a success story. Our customers are very enthusiastic, and next year we will be able to produce profitably from day 1."

Follow the construction of the Fresh-Care Convenience Centre via the Heembouw website.

Text/Photo: Mario Bentvelsen. Artist Impressions: Heembouw/Habeon Architecten.

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Arjan Boer of the Boer & Den Hoedt lettuce farm in Ridderkerk has been using the latest generation Lemnis Oreon LED lighting for the past two years. As a result, he loses fewer plants and is able to deliver premium quality lettuce all year round, even in winter. ‘Our lettuce even tastes better than ever before.’

Almost six year ago today, Boer & Den Hoedt was one of the first lettuce farms in the Netherlands to start using LED lighting. Co-owner Arjan Boer currently has three generations of LED lighting in his four-hectare greenhouse, in addition to a big section that is still illuminated by SON-T lamps. These are, however, due for replacement. Investment costs for LED lighting are high - almost three times as high as for SON-T lamps - but Arjan Boer assures us that the benefits far outweigh the disadvantages. We ask him to explain this to us in greater detail.

Water cooling

One of the unique features of the Oreon Grow Light 2.1 - Lemnis Oreon’s latest generation LED lighting - is the water cooling system, which prevents any excess heat from being discharged into the greenhouse. As a result, crops can be illuminated longer than when SON-T lamps are used, and greenhouse windows can remain closed for longer periods of time. All of this produces positive effects on the quality and growth rate of the lettuce grown at Boer & Den Hoedt.

'When you use SON-T lamps, the temperature becomes too high, which you have to counter with extra ventilation and an ensuing loss of CO2.'

‘Quality is our highest priority,’ explains Arjan Boer. ‘We aim to grow a consistent quality of lettuce all year round. With these LEDs we can illuminate the crop from September through April. When you use SON-T lamps, the temperature becomes too high, which you have to counter with extra ventilation and an ensuing loss of CO2. With this LED lighting system, heat is discharged to a heat pump. We use the pump to upgrade the heat for use later on. We can use it to heat the greenhouse, or to raise the temperature of our irrigation water.’

Illumination level

According to Koen Brabander of PB Techniek, who initially installed the Lemnis Oreon LED lamps, there are even more advantages to the water cooling system. ‘It allows more LEDs to fit in a light fixture, and they give a lot more light. This means that you need fewer light fixtures, which in turn results in less unwanted shade.

Brabander explains that LEDs are also more efficient than SON-T lamps. ‘LEDs emit 2.6 micromoles per second per Watt, while SON-T lamps emit only 1.8, approximately. This translates into electricity savings of 30 - 40%. LEDs also have a longer useful life than SON-T lamps. We think that water-cooled LEDs will last 10 to 15 times longer.’

'At Boer & Den Hoedt we use 90% red and 10% blue light. This LED recipe is the product of many years of testing.'

Boer expects to earn back his investment in six to seven years, despite the high price of 60 cents per micromole. He has distributed the latest generation LED at a distance of one lamp for every 18 m2. According to Brabander, most lettuce growers started with 40 micromoles emitted by SON-T lamps, and the current standard is 80 to 100 micromoles using LED lighting. Some growers even use 150 micromoles of LED light on their lettuce crops.


Apart form the illumination level, wavelength is also important, says Brabander. ‘At Boer & Den Hoedt we use 90% red and 10% blue light. This LED recipe is the product of many years of testing. Tomato growers often use 95% red and 5% blue light. There’s still a lot of research being done to identify optimum wavelengths. In two years, these studies could reveal that crops will perform better under more blue or green LED, for example, but we don’t know that yet.’

‘It saves energy, improves quality and increases production. Additionally, it has reduced plant loss by 10%.'

Boer confirms that his experiences with LED lighting have been very positive. ‘It saves energy, improves quality and increases production. Additionally, it has reduced plant loss by 10%. Our lettuce even tastes better than ever before. We keep abreast of all the latest developments, such as the LED tests currently being conducted in Bleiswijk. We plan to do some tests ourselves, with a different kind of LED light. The entire spectrum is represented in sunlight. Lettuce performs well when illuminated by blue and red LED lighting, but who knows? It could even get better! Of course, that’s the challenge. We want to get the most we can out of it.’

Mobile gutters

Boer & Den Hoedt grows its lettuce under diffuse glazing on mobile gutters, making it one of the most modern lettuce farms in all of Europe. The farm also uses robots that move the young plants to the cultivation area. Sustainability is also a key concern at Boer & Den Hoedt. The irrigation water is recirculated by 100% and the greenhouse features both a double screen and air handling units. Also, Boer & Den Hoedt started growing its lettuce according to Wageningen University Research Centre’s Next Generation Cultivation principle five years ago on account of the energy savings this would enable the growers to achieve.

Roughly twenty-five per cent of Boer & Den Hoedt’s harvest consists of root ball lettuce (lettuce trio) and the rest of several varieties of cut lettuce, including lollo rosso, lollo bionda, oak leaf and frisée. The products are sold directly to supermarkets in the Netherlands, Germany, Scandinavia and the Far East.

This article was published in collaboration with Boer & Den Hoedt, PB Techniek and Lemnis Oreon. Text and photos: Mario Bentvelsen. Video: BrokxMedia.