Christ en Jacqueline Monden of De Kruidenaer in Etten-Leur had hybrid lighting installed in their new high-tech greenhouse, in which they grow basil, just over a year ago. Until now, their experiences have only been positive: a higher production yield, better quality, a longer lifespan and improved plant resilience.
Last year, Christ Monden had a new 14,000 m2 greenhouse built with diffuse glazing, a humidifier and hybrid lighting for the cultivation of basil on water (hydroponics). The basil is grown in six 2,100 m2 containers, which Christ refers to as ‘ponds’. The young plants are started in this greenhouse as well. They are transplanted to ‘floaters’ with plant holes after 1 to 2 weeks. The ponds are located parallel to one another, without any aisles in between. As a result, optimum use is made of the available space.
Short cultivation cycle
On one side of the greenhouse, the floaters with the young plants are set to drift in the water and – after 3½ to 5 weeks – they are lifted out at the other side of the greenhouse for harvesting. This is a short cultivation cycle, thanks to the intensive lighting, which ensures a constant supply of fresh basil six days a week. In addition to basil, the Brabant-based nursery also grows 23 other types of herbs, lettuce (grown hydroponically) and sweet peppers (amounting to a total of 8.5 hectares of greenhouse cultivation and 23 hectares of open-field cultivation with tunnels) for the retail, food service and export industries.
Basil likes warmth, but not too much. In this case, LED lighting is the ideal solution.
In addition to diffuse daylight, the plants also receive artificial light provided by Oreon Grow Light (260 KVA) LED fixtures, in combination with Gavita SON-T (460 KVA) lighting, with a maximum output of 100 μmol/s (the output of the LED system alone is 50 μmol/s). The light fixtures are suspended above the crop in a chequerboard pattern. Their design (lighting plan) and the installation of the system were carried out by Voshol Warmte-Elektrotechniek. Oreon LED fixtures have been installed, among others, at lettuce grower Boer den Hoedt and Koppert Cress.
One of the unique features of the Oreon LED fixtures is its water cooling system. This has various advantages according to Jos Duijvesteijn of Voshol. ‘Basil likes warmth, but not too much. In this case, LED lighting is the ideal solution LED is composed of diodes, which get very hot at the back. Heat is, of course, detrimental to the useful life of electronic devices. Thanks to the cooling system, we can keep the temperature of the lamp between 35 and 45 degrees Celsius, thus substantially extending their useful life (L90 = 35,000 hours, ed.). The heat discharged through this process (50 degrees Celsius) is reused by De Kruidenaer – for heating the ponds, for example. This means that no energy is lost.’
The heat discharged through this process is reused – for heating the ponds, for example.
Christ explains why he chose to install the Oreon LED fixtures: ‘They came out best in a test that was conducted prior to the construction of the greenhouse. The plants grew very uniformly and were super strong. In the end, we opted for 50% SON-T and 50% LED because basil can really use this extra heat. We can light the plants exclusively with SON-T, or exclusively with LED, or with both types of lighting. Thanks to the LED fixtures we can give the plants light for much longer, both in the morning and in the evening, particularly at this time of the year.’
The lighting is switched on as frequently as possible, up to a maximum of 20 hours per day. ‘Last year, I used more SON-T lighting than I had expected. The crop was able to tolerate the extra heat very well. We use SON-T exclusively or in combination with LED, but have not used exclusively LED all that often yet.’ Christ thinks that the LED fixtures were switched on for 2,000 hours last year. Thanks to the LEDs he can give his plants prolonged light and start earlier in the season – four to six weeks each season, he estimates.
We were able to produce the anticipated volumes, and the quality is better. The plants also have a longer lifespan.
The result after growing plants under hybrid lighting for one year is positive. We were able to produce the anticipated volumes, and the quality is better, says Christ. Additionally, judging from customer response, Christ noted that the plants have a longer lifespan. He also has to purchase less product in addition to what he grows in order to meet customer demand. ‘They prefer basil grown in the Netherlands, with a PlanetProof Hallmark (previously Milieukeur). We were able to get through last summer – with temperatures above 35 degrees Celsius – much better than I had anticipated.’
Christ is convinced that the LED lighting contributes to improved plant resilience: ‘During the tests, we noted stronger plans, with sturdier leaves and shorter internodes. The colour was better, too. I am sure that this gives the basil has greater vigour. These results are also reflected in our crops. Basil is a highly demanding crop, a real “prima donna”. Things can be completely different from one day to the next.’
I am convinced that the LED lighting contributes to improved plant resilience.
Although the investment in a new greenhouse ended up being much greater due to the purchase of the LED lighting fixtures, Christ and Jacqueline Monden are very satisfied about the results. ‘We grow almost all the basil ourselves, particularly in the season. What I am most satisfied about is the quality of the crop. We aim to grow the best basil in Europe. In about five years’ time we want to stop growing sweet peppers entirely. It has been going really well until now,’ he says with a wink that shows his marvellous feeling for understatement.
For which types of growers is hybrid lighting interesting? ‘The product range is becoming increasingly broad,’ says Jos Duijvesteijn of Voshol. ‘There are plenty of possibilities in the cultivation of herbs, particularly if heat is a problem. The same goes for growing lettuce. Hybrid lighting is really on the rise among tomato growers. We are currently rolling out the first projects, with LED top lighting in combination with SON-T. A gigantic advantage is that the LEDs will give you a much greater output, with a smaller capacity. This means that you can get more micromoles from the same capacity.
We are very enthusiastic about Oreon’s water-cooled fixtures. This product is stable, and has pretty much be reached the highest level in terms of engineering. Also, once it has been installed there is nothing you need to do. You can also generate a diversity of light patterns with LEDs, for the vegetative and generative growth of the crop. The latter still requires a lot of research, but I can certainly identify opportunities here.’
Medicinal cannabis is excellent for growing in greenhouses with LED lighting. Some varieties of cannabis plants which receive LED light produce substantially more active medicinal substances than those receiving equally intense lighting from SON-T lamps. A study by Wageningen University and Research showed that medicinal cannabis is easy to grow under strong light.
The worldwide demand for medical cannabis is growing rapidly, so there is also an increasing demand for safe, reliable and efficient production methods. Greenhouse horticulture experts from Wageningen University and Research therefore carried out a study in the spring of 2016 to study the impact of growing conditions on the growth and yield of medicinal cannabis. This involved measuring the quantities of cannabidiol (CBD) and tetrahydrocannabinol (THC), among other aspects. Cannabidiol (CBD) is used in the Netherlands to treat various diseases, including Multiple Sclerosis. THC is used to treat disorders such as Gilles de la Tourette syndrome, therapy-resistant glaucoma and symptoms such as weight loss, nausea and vomiting.
The study was commissioned by Lemnis Oreon, developer and manufacturer of LED lighting concepts, and PB Techniek, a supplier to the international horticulture sector.
Source/Photo: Wageningen UR.
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.
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.’
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.’
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.
Holland America Line is entering into collaboration with the acclaimed Dutch grower Koppert Cress. The horticulture specialist aims to start growing micro-vegetables aboard HAL’s new cruise ship, the MS Koningsdam. The cresses will be grown in the ‘Cressomatic’, where the passengers can watch them grow during their cruise.
Cresses are the shoots of individual plants, each with a surprising impact on the senses. The micro-vegetables will be grown at the Culinary Arts Center aboard the MS Koningsdam, a new ocean liner with a capacity of 2,650 passengers. The cress grown in Koppert Cress’ vegetable garden will be added to the dishes ‘a la minute’ by the ship’s chefs, who will be preparing their unique meals in the open-plan kitchen. The cuisine is based on simple techniques based on traditional craftsmanship, allowing the guests to enjoy meals made with freshly grown ingredients during special dinners in ‘farm-to-table’ style.
The Cressomatic for Holland America Line (HAL) will comprise three climate chambers with three cultivation tiers each. This will provide enough space for 441 containers that are filled by Koppert cress with seeds and cultivation medium. The crop will then finish growing practically on its own. The Cressomatic features an advanced climate control system, which regulates the temperature, humidity, light intensity (LED lighting) and irrigation fully automatically. The control systems and settings are based on Koppert Cress’ high-tech production greenhouse in Monster. The Cressomatic was developed in collaboration with PB Techniek. The system satisfies the stringent demands placed on hygiene and food safety applied by the cruise ship sector. Once sown, the little plants can be harvested in just about a fortnight. The various cresses have unique flavours, such as garlic, mustard and liquorice, for a special and outspoken culinary sensation.
Click here for a virtual tour of the Culinary Arts Center of MS Koningsdam.
Bron/foto: Koppert Cress.