The Greenhouse Challenge Grand Finale

Courtesy Guy Ackermans.

A few days ago, the Grand Finale of Wageningen University’s Greenhouse Challenge took place. It was a great day of discussing urban agriculture, showcasing new ideas, pitching, and celebration.

Here’s my experience of that day.

The Stand

At 10 AM, the first members of Green Spark arrived at the Orion building on Wageningen Campus to make our stand as attractive as possible and collect votes from the public.

Our stand had two centrepieces: the spirulina-shrimp system, and an architectural model of our tower.

The spirulina-shrimp system was built by inLoops Tech with the help of Emilio from our team. This was no puppet show – it contained live shrimp and spirulina.

Emilio showing off our newest set of gadgets to the ladies.

The model of our tower had been built overnight and into the late morning by our tenacious German architects. The parts were laser cut in Aachen and brought to Wageningen a day earlier. They were still gluing it together at the stand and it attracted quite some attention.

The tower, with its glue still drying, was the second centrepiece of Green Spark’s stand.

Opening Symposium

Our host Tracy Metz and the panel of experts. Courtesy Guy Ackermans.

The opening symposium was hosted by Tracy Metz. There were a number of talks and discussions about the challenge and policy surrounding urban agriculture. Speakers and panel members included:

  • Ernst van den Ende, director of the Plant Sciences Group at Wageningen University
  • Nona Yehia, co-founder and CEO of Vertical Harvest and principal at GYDE Architects
  • Dr. Nevin Cohen, Associate Professor at the City University of New York (CUNY) Graduate School of Public Health, Research Director of CUNY’s Urban Food Policy Institute
  • Dr. Jan Willem van der Schans, urban farming superstar and researcher at Wageningen Economic Research
  • Prof. Gert Spaargaren, professor of Environmental Policy for Sustainable Lifestyles and Consumption at Wageningen University

Breakout Session on Energy

Left to right: Mariëlle, Gert, Rosanne, and Leo.

This breakout session was moderated by Gert Spaargaren. Three points were discussed. After hearing three experts’ opinions on this, we voted with our feet and discussed. The three experts were Leo Marcelis, Mariëlle de Sain, and Rosanne Metaal. It was interesting to see that the group was quite evenly balanced on all three points, which created an open discussion.

Point 1: It will be (almost) impossible to realise zero-carbon greenhouses that can produce climate-friendly food in a high-tech, sustainable way.

My thoughts: Firstly, ‘almost impossible’ is an interesting concept! I disagreed with this statement. Those who disagreed with this statement said that there are already examples of greenhouses that are carbon neutral. I also thought it depended on the system boundaries. If you think of the land saved, which could be reforested, urban greenhouses might be carbon-negative.

Point 2: Urban greenhouses should become lead actors in growing and producing low-carbon food, but by also actively organising the energy transition at the neighbourhood level to green cities.

My thoughts: I was neutral on this one. It depends on the local context. Smart cities need to make best use of all energy sources and sinks. In some places, urban greenhouses will play a large role. In others, they won’t. Either way, having them participate isn’t a bad idea.

Point 3: The power of the green tower over its connected local residents should be restricted to activities with voluntary participation.

My thoughts: This was more a policy-based point than a technical one. I agreed with it. Of course it depends on what ‘voluntary’ is, which brings up the democracy paradox (is voting against democracy something that should be done?), but making things voluntary is more sustainable and arguably more ethical. After all, local residents are the ones living with the consequences of the decision. Forcing things on people only widens the gap between the intellectual elite and everyone else, as Leo Marcelis said.


Max and I pitching Green Spark’s concept to the jury. Courtesy Guy Ackermans.

This session was opened by Arthur Mol, Rector Magnificus at Wageningen University. Before the pitches, Cindy van Rijswick from Rabobank gave a talk on Rabobank’s view on vertical farming. One of her main points was that vertical farming had more opportunities in the Middle East and East Asia than in Europe.

All 14 groups pitched in front of the jury:

Green Spark was one of the last groups to pitch. You can see Max and me present here:

The video doesn’t always load at the right time reliably, so you may need to manually set it. Our pitch starts at 1:42:30.


And now, the final moment we had been waiting for.
Overall award: GreenWURks – congratulations!

Audience award: Technotitlan
Outstanding architecture award: ThanksWork
Innovative substrate award: Green Spark (that’s us!)

The innovative substrate award was awarded by Sjors Beijer from Klasmann-Deilmann, a company making substrates. One of my favourite moments was when the host asked Sjors how he could make the term ‘innovative substrate award’ sound more sexy. His response was something along the lines of nobody cares, if we want all of this urban greenhouse malarkey to happen we’re going to need substrate. Touché, Sjors. Our innovative substrate award was largely down to the work of Sean, who had spent months researching biochar/sawdust/soil combinations with proper experiments. Kudos to Sean!

Sean and Sjors discussing biochar, which Klasmann-Deilmann have also been researching.

When we were given the award, the host also told us we should ‘work on our gender balance’. Many of us found this very strange and silly. Let’s just grow food in a healthy and sustainable way. I’ll leave it at that because it would be ironic to spend too many words on it here, but too much of this blue church politically-correct rhetoric permeated the event.

Afterparty and Beyond

After tidying up our stand, the next stop was Droevendaal for a fire-lit party with the other teams.

Look closely and you’ll see that some of the flames are green. This is none other than a sign from the cosmos.

What’s next for Green Spark? The next Greenhouse Challenge will take place in 2 years’ time and will be focused on China. 2 years is a lot of time to refine our ideas, and I’m happy to say that a strong core in our team is willing to carry on improving our concept for then.

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