Home Posts Tagged "vegetables"


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Research scientist Wieger Wamelink and student Line Schug of Wageningen University & Research have been conducting research into finding suitable locations to grow vegetables on Mars. Using data from a series of maps of Mars, they drew up a 3-D map showing the best sites for growing vegetables on this faraway planet. Information about suitable cultivation sites is crucial for the possible colonisation of Mars, because growing food crops will be one of the key tasks for the first astronauts.

To obtain the necessary data, the research team made use of several maps of Mars that were made freely available by NASA, Arizona State University and JPL. “This research was made possible by the abundance of data about Mars that is now available,” explains Wieger Wamelink.

Key figures from outer space

The maps used by Wamelink and Schug provided insight into such information as the mineral composition of the soil and the presence of heavy metals. In addition to this, they also provided information about the calcium content of the soil, the climate and temperature, the terrain elevation and the radiation levels on the planet.

No open field cultivation

According to the data gathered by Wamelink and Schug, they were able to calculate the suitability for growing crops for each location individually. Food will, however, be grown indoors on Mars because the outdoor circumstances on the planet make growing crops in the open field impossible. “There is almost no atmosphere, the outdoor temperature is 50 to 60 degrees below zero on average and cosmic radiation is intense,” explains Schug. Growing vegetables will therefore probably be easiest underground.

Positive cultivation factors

Despite the fact that crops cannot be grown on Mars in the open field, the terrain conditions and the temperature will nevertheless have an impact on choosing the best possible site for plant growth. “High levels of heavy metals in the soil and strong radiation make a location unsuitable for growing vegetables,” says Schug. “Relatively high temperatures or calcium content and a relatively flat terrain are positive environmental factors with a view to establishment and growing vegetables.”

Landing site

An inventory made by Wageningen UR reveals that a number of favourable sites for vegetable cultivation overlap sites where landings have been made, or are planned. This is good news for projects whose objective is the colonisation of Mars. If the planet were to be colonised, it is crucial that vegetables are grown near the landing site. The 3-D map created by Wamelink and Schug shows that the Mars Pathfinder and Viking 1 both landed on sites that are suitable for growing crops.

Food for Mars and Moon

Charting out suitable locations for growing food on Mars is part of an overarching research project called ‘Food for Mars and Moon’, and for which Wageningen UR is investigating possibilities for growing vegetables on Martian and lunar soil. Up until today, the University succeeded in growing ten different types of vegetables on Martian and lunar soil simulants.

Source: Wageningen UR. Photos: SAIC.

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Organic wholesaler Eosta in Waddinxveen is labelling more and more fruits and vegetables using a laser. Others are also discovering this sustainable labelling method. Not only will this save tons of waste, there are more advantages to laser branding.

Eosta from Waddinxveen was the first to start using this technology, called natural branding. Michaël Wilde of Eosta: “We have been delivering ‘natural branded’ products to various supermarkets in Sweden, Belgium, Germany, Austria and the Netherlands (Hoogvliet and Albert Heijn) for six months now. These products include courgettes, squash, sweet potatoes, avocados, ginger, mangoes and cucumbers.”

Less waste

He continues: “For one customer – ICA in Sweden – we calculated how much plastic we are saving. This is 750,000 items of packaging a year! That’s enough foil to wrap around the entire globe – twice!” The Hoogvliet supermarket also calculated how much plastic they will be saving by applying natural branding to 85,000 organic avocados and 20,000 pieces of organic ginger. “That’s more than 100,000 a year. As an innovative company, we consider this to be very important. An innovative invention that will allow us to achieve considerable savings on packaging”, says Ed van Venrooij of Hoogvliet. Nevertheless, plastic also has its advantages. They recently conducted a test at Hoogvliet supermarkets: sweet peppers packaged in plastic remained in good condition for four to five days longer than unwrapped sweet peppers. “We had to discard 17% fewer sweet peppers. That is also worth something”, says Van Venrooij.

Higher inventory turnover

According to Michaël Wilde of Eosta, not using plastic foil has another advantage: “Various studies – including one conducted by Wageningen Research University – revealed that consumers are more inclined to buy organic produce if it is unpackaged. This means a higher turnover rate, and therefore eliminates the problem of perishability. Additionally, 70 to 80% of all organic products are packaged. This is not so much to extend their shelf life, but to make the distinction between organic and non-organic products. Only a few products are packaged in plastic with a view to extending shelf life or to keep small fruits together, like blueberries, cherry tomatoes and grapes.”


The technology works as follows: using the low-energetic carbon dioxide laser, the outer layer of the peel or skin is heated locally. This causes the pigment to evaporate. According to Eosta this process is extremely superficial and has no impact on the flavour, aroma or perishability. Laser-branded peel or skin is perfectly edible. The method is suitable for all sorts of fruit and vegetables, but not for oranges, mandarin oranges, lemons and pomegranates due to the self-restorative property of the peel. After a few days, the markings would therefore no longer be visible on these fruits.

Other businesses

Besides Eosta, wholesalers in the UK and Spain have also started laser branding. In the Netherlands, the Cool Port Packing Rotterdam (CPPR) packaging company plans to start using this technology in the last quarter of 2017. Laser branding devices can be used to burn a logo, text or message into the peel of the relevant fruit or vegetable. The thickness of the peel is of no consequence. Up until now, the laser has been tested on ginger, avocado, citrus fruits, melons and pumpkins. According to CPPR the method is environmentally-friendly, safe and EU-approved.

Source: NOS/Eosta/CPPR. Photo and video: Eosta.

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I’m writing my first column for In Greenhouses sitting in the departure lounge at Schiphol Airport in Amsterdam. The reason for my three-day trip to the Netherlands was a joyous one: our daughter Wendy turned 30 yesterday, and as her proud father, naturally I had to be there. All the children and grandchildren were there this afternoon, and now I’m already on my way back to South Africa.

South Africa has been our home since 2014. After many years of travelling and deliberating, we ultimately decided to follow our dream: to be there for the people of Africa. We live and work in South Africa. Anne, my wife, is involved in development work for disadvantaged children, and I am a consultant for Delphy specialising in covered vegetable growing in eastern and southern Africa. Basically that means advising and training people in safe food production to enable them to create jobs and produce safer food.

Horticulture, and in particular covered crop production, has been gaining rapidly in significance in Africa in recent years. There are many reasons for this, with water shortages topping the list. As many people are aware nowadays, it takes five times less water to grow a kilogram of tomatoes in a greenhouse or tunnel than it does in the open air. Protection against wind and rain and keeping pests out are other reasons for growing crops under cover.

It’s much easier to grow food safely and sustainably under cover. Funnily enough, it has mainly been private initiatives and not government ones that have set this movement in motion here. Supermarket chains like Woolworths have been setting the trend for years with the Farming for the Future programme. As a result, growing in an environmentally sound way now tends to be the rule rather than the exception for modern GlobalGAP certified growers. But there are still a lot of smallholder farmers growing for the wholesale markets where certification is not yet a requirement, although it is a USP for them. In my next column I will be looking at how this works in practice and what role I can play in it myself.

Herbert Stolker
Senior Consultant Africa

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Although they only started growing fresh algae commercially less than a year ago, Hendrik Staarink and his partner Stefano Canziani are fully confident about the future of their business, which they called Algreen. ‘Algae are the vegetables for the future.’

Starink started his studies in Agricultural Water Management at Wageningen University in 2008 and conducted the research for his final project near the Oosterschelde tidal basin in the province of Zeeland. A few visits to crustacean and seaweed farms further kindled his enthusiasm about algae. After reading several books on the cultivation of algae that summer the ball started rolling rapidly.

"We saw some excellent commercial opportunities, taking into account the high prices paid these days for Spirulina algae."

While he was at university he met Stefano, who was studying biotechnology and shared his fascination for algae. ‘We visited algae farms in France together. These are commercial farms, but they were very open about what they were doing. We studied their cultivation system, which they call raceway ponds. Almost all commercial algae are grown in raceways these days. We saw some excellent commercial opportunities, taking into account the high prices paid these days for Spirulina algae. So, we decided to try our hand at this, too!’


‘We first grew Spirulina on an experimental scale in 2014, which marked our first step out of the lab. A great deal of research has been done on the cultivation of Spirulina and we worked with tested techniques and a type of algae that was adapted to the climate in the Netherlands. As a result, we started production on a bigger scale in 2015. We now have an office in Wageningen and grow our algae on a nearby cultivation site.’

"We are directing our sales primarily at the market for healthy juices and good restaurants."

Spirulina is primarily eaten on account of its relatively high protein content. ‘I would like to call it a superfood, but that applies to other vegetables as well. To me, it’s a very special vegetable.’ Spirulina is also chock-full of easily absorbed protein, is an important source of vitamins (e.b. potassium), minerals (particularly iron) and antioxidants (phycocyanine). As a result, it can easily be included in a healthy diet.

Who will be buying your fresh algae?
‘One of our first steps was to conduct market research. We discovered that the market is growing, and that our product is healthy, not too expensive and has numerous uses. You can put it in virtually everything. Many people eat it as a dietary supplement. We are directing our sales primarily at the market for healthy juices and good restaurants. We are a supplier to various small-scale juice bars and shops in Amsterdam. Businesses like that often use powdered Spirulina, and are now replacing this with our product. They tell me that it tastes much better.’

Why do you consider algae to be the vegetable of the future?
‘Because it’s such an easy crop to grow! Harvesting is simple: there’s nothing that needs to be picked or cut. Also, the cultivation of algae can easily be automated and up or downscaled. You don’t need a lot of energy; just a little sunlight. We produce our algae in an unheated greenhouse. Also, we don’t use any crop protection agents. Algae have few requirements with regard to the quality of water (salt content) and don’t emit any greenhouse gases. It’s a very sustainable crop.’

"We distinguish ourselves from the competition by offering a product that is not only fresh, but also sustainably grown."

‘In a conventional greenhouse you need ventilation, which we have no need for. We already apply the principles of Next Generation Cultivation. You see a lot of technology applied to algae that look very interesting on paper, but that are simply not feasible from a commercial perspective. We keep it as simple as possible and make it as complex as necessary. We distinguish ourselves from the competition by offering a product that is not only fresh, but also sustainably grown.’ By offering the algae while they are fresh they not only taste better, but also retain more of their nutrient content, adds Starink. ‘Plus, it cuts costs, because drying the algae requires extra energy.’

Will every grower with access to a tank of salt water be able to grow algae in the future?
‘It’s not quite that simple. Growing algae requires a certain degree of craftsmanship. There’s actually a lot you need to know about: cultivation, certification, biological testing, microscopic testing, harvesting, processing, and so on. We studied the entire process in minute detail. In addition to that, we optimised the cultivation conditions for our algae. We prepare our own nutrient mix. Still, what we do can easily be compared to what other commercial growers of vegetables do.’

"If you operate on a large enough scale you should be able to produce algae profitably in the Netherlands with the variety we developed."

When asked what his production yield is, Starink keeps silent. ‘Even in a cold greenhouse we can earn a little. However, cultivation at this scale takes a lot of labour, relatively speaking. If you operate on a large enough scale you should be able to produce algae profitably in the Netherlands with the variety we developed. We grow an adapted Spirulina variety obtained through selection.’

What will your next step be?
‘Our next challenge is to start operating on a larger scale, cultivation-wise. We would like a bigger greenhouse, preferably with residual heat, to eliminate our winter dip in production. Our most serious competitors are producers of dried algae. We can say that our product is better, but if our fresh algae will become much more expensive, we will be fighting a tough battle,’ explains Starink.

"There is a lot left to discover in the underwater cultivation of vegetables."

‘We are also engaged in expanding our product range. There is a lot left to discover in the underwater cultivation of vegetables. Additionally, our customers keep asking for more varieties of healthy and tasty algae. We are currently busy developing an exceptionally tasty variety of seaweed (a type of macro-algae) and keep our knowledge and expertise about micro-algae up to date through projects like the ‘Luteine 2.0’ project, which won us a prize from the Netherlands Organisation for Scientific Research (NWO). We are currently speaking to investors to enable the business to continue growing and so that more people will be able to enjoy locally grown, super-fresh algae produced by Algreen in the future.’

For more information, have a look at this video about fresh Spirulina (English subtitles) or visit the Algreen website (Dutch only).

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Key points for attention in the online sale of fruit and vegetables are quality and food safety. Another factor to take into consideration is packaging. Can standardised packaging guarantee the desired product quality, food safety and customer experience standards?

Although no specific rules apply to online sales - as opposed to traditional sales methods - online sales channels will need to observe the same quality and food safety regulations as other food suppliers. ‘Food safety is a priority issue,’ says Nicolette Quaedvlieg, policy officer for Quality & Food Safety at het GroentenFruit Huis.

'People are less disappointed when they pick up a product at the supermarket with a quality defect than if they had bought the same product with the same quality issues online.'

She also believes that the quality of online products should be better than what is offered by supermarkets. ‘You have to take it one step further. People are less disappointed when they pick up a product at the supermarket with a quality defect than if they had bought the same product with the same quality issues online. That’s simply not acceptable to them.’ Additionally, Quaedvlieg points out that consumers purchasing produce online need information about the product’s country of origin. Online sales platforms are also required - just as shops and restaurants - to provide information about allergens, both on their websites and upon delivery to the customer.

Best quality

Martijn van Andel of JEM-id is also convinced that consumers should get the best possible quality when they order something online. ‘And that’s possible, because you leave out several links in the distribution chain. Going grocery shopping three times a week is actually ridiculous, since 90% of the products you buy are identical. Neither is grocery shopping a particularly interesting experience. There are few people who genuinely enjoy shopping for groceries.’

'Consistency in quality and freshness is only possible through short lines and foolproof chain cooperation with preferably local suppliers.'

Harrij Schmeitz of the Fresh Informationmanagement Center emphasises that the quality of online groceries not only needs to be good; it must also be consistent. ‘The consumer must not be disappointed. If consumers fail to find the quality they seek online, you will lose them and they will purchase their products elsewhere.’ Consistency in quality and freshness is, according to Machiel Reinders, senior researcher at LEI Wageningen University Research Centre, only possible through short lines and foolproof chain cooperation with preferably local suppliers. ‘Good customer service is also of paramount importance.’


The range of packaging currently available can only partially guarantee the desired standard of quality and consumer experience, says Reinders. He indicates that there is a demand for better packaging, particularly for more delicate products. ‘Special packaging is also needed for the cooled transport of products. PostNL has conducted several experiments with Vershuys.com, for example, in which they explored the possibility of using special coolers for the shipment of fresh food products.’

'The range of packaging currently available can only partially guarantee the desired standard of quality and consumer experience.'

The researcher also points out that packaging can also enhance consumer experience through the addition of supplementary information, or visual materials, for example. ‘On the other hand, one of the trends in modern society is to desire to curb the amount of packaging waste. To put it briefly, there are still plenty of opportunities for innovation in the field of packaging fir the online market. This is one of the issues on which the Fresh ONLINE Pack project will be focusing in the next few years to come.’

Text: Tuinbouwteksten.nl/Ank van Lier. Photo: HelloFresh.com

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The consumption of fruit and vegetables is declining. The purchase of fresh vegetables by consumers dropped by three per cent and the purchase of fresh fruit by half a per cent in 2015. This trend has been growing for some time. According to Nicolette Quaedvlieg of GroentenFruit Huis there is still a world to conquer in this respect. ‘The online market offers a lot of new opportunities. Businesses are looking for new markets and models for their distribution.’

However, Quaedvlieg is also aware that the online sale of fresh produce is lagging behind the sale of other consumer and other goods. ‘People buying fresh products want to be able to see, touch and smell them first. Additionally, one type fruit or vegetable can easily be replaced by another; the internet offers more added value in the sale of consumer goods.’


Nevertheless, Quaedvlieg believes there to be ample opportunities with regard to the online sale of fresh produce. ‘There are outstanding opportunities if you can offer a unique product that is not available anywhere else, for example. Or if you can add something interesting to your products, like a recipe. Customer loyalty is also very important; people will come back once they know how tasty your products are. Consumer experience is a key factor in this.’

'Customer loyalty is also very important; people will come back once they know how tasty your products are. Consumer experience is a key factor in this.’

Quaedvlieg is also convinced that selling your products online enables you to enter into closer contact with your customers, which is a considerable advantage. ‘It’s easier to get feedback, from which you can gain a great deal of information. However, if you don’t make use of this it won’t be any help to you. This service is very important to consumers.’

Text: Tuinbouwteksten.nl/Ank van Lier. Photo: GroentenFruit Huis.

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JEM-id is based in Honselersdijk and develops websites and software. Ninety-five per cent of its clients are active in the fresh produce and ornamental plants sectors. Account manager Martijn van Andel has experienced the rapid growth in online sales achieved in the past few years by the ornamental plants sector, while according to him the the fresh produce sector lagged notably behind.

Van Andel explains that the diversity of the products in the ornamental plants sector is much greater than that of the fresh produce sector. Apart from this, consumers want to see fresh food products before buying them. ‘Even if you’re speaking about the same product, there are notable differences. No two moth orchids (Phalaenopsis) are alike. The number of branches will be different, as well as the quality, the packaging, and many other aspects. You really buy a specific article. This is why people are looking for ways to clearly and efficiently present the diversity of their products. Good photographs, taken at the growers’ place of business, are very important in this.’

This is different in the fresh produce sector, and the differences are less obvious. ‘If you order a five-kilogram box of red sweet peppers, diversity will be very limited. Everyone knows what you mean and nobody actually needs to look at the products before buying them. In this respect, ordering fresh produce is easier than ordering ornamental plants.’


JEM-id developed the FloraXchange online communication platform especially for the potted plant sector. This platform provides support to growers in advertising their offering of potted plants. There are currently 1,059 growers affiliated with FloraXchange who present their products on the website. JEM-id makes this information available to more than 300 buyers, who in turn forward this information to their own customers. ‘It is quite revolutionary in the market. I venture to claim that this initiative has given the entire sector a boost. It provides in a demand; we have obtained a lot of positive response.’

According to the ICT specialist, trade companies really wanting to boost their sales have to make sure that their internal automation and logistics processes are in order. This means that a lot of their old systems will need to be replaced. Of course, not everyone is equally enthusiastic about this. ‘If you are a leading exporter of fresh produce or ornamental plants and you have to replace your internet systems, this will cost you a lot of money. This will, of course, have a huge impact, while the success ratio can be called quite exciting in terms of feasibility. There are many companies who keep putting this off. However, you have to embrace change rather than avoid it; at this point you have no other choice. You have to change with the times. This is the only way to survive in a world where the only constant is change.’

Purchase moment

According to Van Andel, there are still plenty of opportunities in the consumer market, both in the ornamental plants sector and the fresh produce sector. Logistics plays an important part in that respect. ‘Although there are special boxes available these days for shipping plants, shipping shoes is still a lot easier. Besides this, plants are impulse products. You don’t decide to buy a plant when you’re sitting on the couch in the evening with your laptop; you decide to buy one when you’re at the garden centre or the supermarket.’

However, the ICT specialist is surprised that the trend of buying groceries online is lagging so far behind. At the same time, he offers some plausible explanations for this. ‘Ordering a packet of macaroni, a jar of pasta sauce or a carton of yoghurt online is easy. But it’s different when you’re buying fruit or vegetables. If you regularly buy produce at a supermarket, you know that the freshest mushrooms aren’t the ones stalled out in front, and that the quality of green beans is variable from day to day. This is preventing a lot of consumers from buying these products online.’

One of the aspects that should be taken into consideration is customer perceptions at the moment of sale. ‘Buying a computer online is a lot more fun than buying one at a shop. Mediamarkt may have the lowest prices, but when you buy a computer there you will be helped by an eighteen-year-old in an ill-fitting jacket. On the other hand, when you buy a computer via Coolblue, you are not being pestered by anybody trying to sell you a more expensive product, you can consult hundreds of user reviews and your computer will be delivered to your home the next morning. It’s clear who will be winning this race.’

Text: Tuinbouwteksten.nl/Ank van Lier. Photo: JEM-id.

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The online market for fresh produce and ornamental plants is growing. However, while the ornamental plant sector is making giant steps forward in this respect, the food market is lagging distinctly behind, particularly with regard to fresh produce. How can this be explained, and what are some of the opportunities and threats facing the online sale of horticulture products? Four parties engaged in this field present their vision on the developments, each based on their own expertise.

The number of consumers preferring to make their purchases online is constantly growing. Not only do they buy their clothes and shoes online; they also buy their food on the internet. The percentage of fresh produce sold online, however, lags far behind that of other product groups.

This can in part be explained partly by the high supermarket density in the Netherlands and partly by a lack of consumer confidence in the quality of fresh fruit and vegetables offered online: they prefer to see - and even touch - these products before buying them. Additionally, they are reluctant to pay additional shipping and delivery costs. On top of that, many suppliers of fresh produce lack a successful business model, particularly due to the logistic complexity associated with online sales. There are still many challenges ahead!

Online groceries

Nevertheless, various people engaged in the online sale of food products believe this to be a highly promising market. A study conducted by LEI Wageningen University Research Centre at the beginning of 2015 showed that approximately 12% of all Dutch consumers order their groceries on the internet from time to time. Another study, conducted by Deloitte in 2015, revealed that 8% of all consumers have, at one time or another, made use of an online ordering service. This service is used once or twice a month and the average amount per online order is approximately 69 euros.

Groceries ordered by respondents (or that they would like to order) online are mainly products with a longer shelf life, dairy products and frozen food. There is, however, also a notable rise in the number of fresh products ordered online. The emergence of meal boxes, of which more and more are being offered by supermarkets and other retailers, plays an important role in this development. This relatively new concept is benefiting from the popularity of regional products, healthy nutrition, organic ingredients and several intensive marketing campaigns launched by leading international players.

Meal box increasing in popularity

The meal box is becoming increasingly popular among Dutch households: A recent survey by Multiscope showed that, as it stands today, 11% have tried out a meal box and one third of them will continue to order them. Two out of ten people in the Netherlands are interested in the concept, but have never ordered a meal box. These are generally households composed on one or two persons. What appeals to them in particular is the convenience, the variety in meals and the inspiration to try new recipes.

HelloFresh is the best-known meal box. Eight out of ten people in the Netherlands has heard of this brand. Users are most satisfied about the originality and good quality of HelloFresh box. However, the price and freedom of choice in the various varieties received a lower score. HelloFresh does not deliver its meal boxes on Monday, which is the preferred delivery date. Allerhande Box, however, delivers on Monday and is second to HelloFresh when it comes to name recognition (49%).

Text: Tuinbouwteksten.nl/Ank van Lier. Photo: Fresh Informationmanagement Center.

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Urban farming is currently a hot item, capturing the interest of people all over the world. The roof of a former Philips building in The Hague is currently the scene of a large-scale 1,500 m2 urban farming project developed by UrbanFarmers and Priva for the cultivation of exclusive vegetables in combination with fish farming. Will urban farming, with cultivation on rooftops or indoors assisted by LED lighting, help shape the future of horticulture?

‘Urban farming is a hype. I get questions about this every week, and sometimes even every day! Many people believe that this is the solution we have been waiting for to alleviate world hunger. I do not share this conviction; simply because it is too expensive for bulk production.

I do believe that marketing concepts in big cities, with rooftop cultivation or cellar cultivation by restaurants, for example, are feasible. Consumers who find this appealing would be prepared to pay twice as much. You could also produce crops with a higher vitamin and nutrient content, which could be achieved through better crop control by using LED lighting, for instance. Consumers might very well be prepared to pay a higher price for this.

‘Rooftop cultivation at standard prices? I doubt that this is possible. Greenhouse cultivation on 10 hectares of land with only one crop type for efficient production is no longer unusual, but you can’t compare this to rooftop cultivation on a very limited surface area. Even if it is easier to control all the cultivation factors, it still has to be economically feasible. This is only possible if added value is offered that the consumer is willing to pay for.

‘I once saw a television commercial in Japan for vegetables, grown using LED lighting by employees wearing full laboratory clothing. The concept of growing healthy vegetables is entirely different in Japan. I wonder how the average European consumer would respond to this? Would he consider it to be rather artificial? And I’m not even taking the economic feasibility of this option into consideration.

‘There are many urban myths about the possibilities offered by urban farming. There will, without a doubt, be a market for this - one where products are sold that contribute some form of added value. This would certainly be possible in metropolises such as New York and Shanghai, also in terms of consumer experience. However, you can grow food in greenhouses located on the outskirts of such cities very effectively, all over the world.

‘We are investigating the cultivation of plants using only artificial light. We have access to all the knowledge we need to do this, and this approach to cultivation approach may indeed be feasible. However, we are still faced with the social aspect and the economic feasibility. Aside from that, I believe it could be possible to carry out specific phases in the cultivation process in climate chambers; phases that have a higher probability of something going wrong in the greenhouse and where the volume of plants is not so big. This would be particularly useful in the early stages of cultivation.’

There are consumers who cherish romantic ideals with regard to open-field farming.

‘Those people forget that greenhouse horticulture offers distinct advantages with regard to the consumption of water. In the Netherlands, the availability of water is generally not an issue. There have, however, been instances where hosepipe bans were imposed on growers of open-field crops on sandy soil in Limburg and Brabant in dry summers. The collection of rain water in greenhouse horticulture is not always sufficient, and in those cases the alternatives available to growers are not always adequate.

‘The availability of water on a global scale is a much bigger problem. The cultivation of one kilo of tomatoes in Israel or Spain requires 60 litres of water. When grown in a greenhouse, 30 litres will be sufficient. In the Netherlands, this is only 15 litres. Cultivation in a closed greenhouse requires even less water, because you can cool down the air temperature and collect the condensed water.’

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.