Rond BlueCity

Three new experimental green walls in BlueCity – Green Wall Hackathon


During Dutch Design Week, BlueCity Lab and Scape Agency organized a Green Wall Hackathon. 15 design professionals took on the challenge to realize three green or living walls in or around BlueCity in Rotterdam. The experimental green walls resulting from the hackathon will continue to grow for one year with the aim to grow into scalable solutions that can be applied to many walls across multiple cities.

In this article we’ll summarize our key take aways of the hackathon and share the three concepts. If you want to more about these green walls, don’t forget to follow BlueCity Lab on Instagram. Or jump on your bike and come take a look yourself!

Three walls, three different solutions

1. Living Curtain: a natural climb of four plant types

Living Curtain is a concept by a team of designers (Christina Michael- Inbo, Kasia Horodynska – Urban Hedera, Nafsika Efklidou – Inside Outside and Tom Schouw- Studio Tom Schouw), which explores the ambiguous relationships between man, nature and the city.  The concept consists of four different groups of climbing plants that are competing in a green race to reach the top of a 7m grey, uninteresting, corner wall. Which one will reach the top first? The plants are assisted by a ‘’curtain’’ hanging from the top of the wall, made of chains of different materials and thicknesses. The chains act not only as a climbing support for the plants, but also as a way of collecting and directing water to the plants.  Reused nets will also be implemented as fog harvesters to collect water during dry periods in the summer.

Through a minimal structure that will have an immediate and big scale impact, both architecturally and in terms of greening, this project aims to completely transform a previously neglected part of the BlueCity façade.

2. Inhabistad: creating space for biodiversity

Inhabistad is a testing ground for a brown facade concept. It is a miniature city that creates habitats for urban biodiversity. Inhabistad is a low-tech, low-maintenance and cost effective solution. Beautiful in its early brown state, the facade becomes greener over time. As a modular system it can be arranged in different compositions and applied at various locations. The modules are shaped from contoursheets; holed steel sheets and waste products from the steel-cutting industry close to Rotterdam. For this prototype, 3 kinds of soil are tested; one based on construction waste, one based on Blue City organic waste and a forest-like soil.

Design and execution team: Karola van Rooyen, Anneloes Kattemölle, Alice Berten and Joris Maes Supported by: BlueCity Lab, Blacon, Scrap, Superuse and RD onderhoud.

3. Blue Season: Green Wall as a Service

The plan Blue Seasons is a concept for a green façade which opens the gates of BlueCity to the public. Carel Soer (RainBlocks), Huub Looze (OmLab & Avans Hogeschool), Laura Prinzen (student IPO), Bart Keunen (SimpelSedum) and Krista Werker (Stichting Miep) created this modular wall with green content searching for interaction with visitors, passer-by and curious community. Blue Seasons is a façade with tangible lush living green. They anticipated the difficult climate on this northern façade. It’s designed in a technical realistic way (built in search for an eco-friendly construction) with the potential for an innovative economic model: Green Wall as a Service. They connect nature friendly organisations and invite schools to participate.

Seven learnings from the hackathon

1. High tech solutions cost lots of material (and money, and maintenance).

When making a green wall, you can basically go two ways, @Lars van Vianen (@Scape Agency) explained in our kick-off: planting along the wall (living walls) and planting against it (a green wall). The easiest and most natural solution is to put the right plants for the location in the soil and provide them with the optimal conditions to grow up, supporting some of them with a climbing rack or wire. The most technical solution was presented as inspiration to our group by @Robert Geurts and Coen van Vreden from @Inbo Architects. They explained how they engineered the green in the Vertical Forest of the Valley (@MVRDV) and the skyscraper designed by Stefano Boeri in Utrecht ”

2. Climbing plants do not harm a modern wall.

Fear of many real estate managers is that strong climbing plants like ivy (hedera) and vine (parthenocissus) harm their wall. These risks can be easily tackled by choosing the right plants. Only old walls are harmed by the climbers, since the cement wasn’t strong enough. Walls created after 1950 have little to fear from climbing plants.

3. Supporting materials: biobased or fossil?

To keep nature in place, you need a barrier that does not degrade to ensure a safe construction or moist not to harm the wall (in case of the brown wall, the team used second hand pvc banners to protect the wall from the soil. The chains of the living curtain will most probably be made from iron (since in the coming years, they need to uphold the climbing plants). A chain or wire along the wall can stay there for many years, offering the support the plants need to climb up. What would be the biobased solution for this, one of the jury members Pascal Leboucq from Biobased Creations wondered.  The point with using biobased materials for natural solution is of course the biodegradability. Hemp rope is amazingly strong, yet who checks when the rope is degraded and what it does for safety of the construction. Anyone having great ideas on this respect?

4. It’s the soil, stupid.

Max de Corte, one of the initiators of the Food Forest Kralingen and member of Coöperatie Ondergrond (Cooperation Underground) explained to the group during a corona proof walk in the food forest that healthy plants start with healthy soil. Also Hans Engelbrechts, the gardeners behind the Nieuwe Tuin, an experimental garden for wild nature in the city, enhanced the importance of this. Ilya Toornvliet, with her company “De Stadstuinier” helped the group to create a strong soil and showed how she determined the recipe of mycorrhiza, clay, compost, sand and of course: attention and love to give the plants a great start. The Habistad team created various mixes of soil as a test of what would work best, including one with mycelium from Rotterzwam (a BlueCity-based company growing oyster mushrooms on coffee waste).

5. The right plants for the right place.

Some plants like shadow, others like sun. Most of them like space and no interference by us humans. Interestingly, most climbing plants are forest plants, wanting to climb up to the sun. All experts helped the team during the design process to think like plants and animals they want to provide shelter to. What do these species need to flourish? The Habistad team created an invitation for nature to start growing in the soil they made available, inspired by a concept that is called brown roof.

6. Designing with living organisms requires totally different skills.

To be able to go behind a “boring” ivy green wall that will still flourish over time, you need to know a lot about plants and the conditions they need to grow in. What distinguishes the designers from the gardeners when working with nature? The learning here is that we realized jobs and assignments will change and we need each other’s knowledge to create smart solutions.

7. Who is responsible for the maintanance?

Since it is alive (plants!), someone needs to care for them, especially when it is a hot summer, or the soil is new. Teresa van Dongen, biologist and artist with many biodesigned projects on her name shared how one of her green facades was supposed to be managed by a company that in the end was not involved with her facade any longer. The question of ownership is also in the experiments that grow around BlueCity a pressing one: although we are a circular example city, it is not as if we have a person available for managing all green.

Action needed to grow more green walls

The only way to get more green in our cities is to make space for green in our cities. As simple as this sounds, it requires participation from many disciplines to get this into action. Thanks to all participants for their dedication, to all speakers and experts who joined this hackathon to share their experiences and to our partners Biobased Creations, World Embassy Circular and Biobased Buildings and Creative Industries Fund for their support. Next step is to organize an experts meetup to share learnings on this topic with relevant partners like the municipality and construction partners of BlueCity to engage them in this dream of creating space to grow more green walls.

What are your experiences with vertical green? Do you recognize our learnings of valuable knowledge to add? Please drop it at or leave a comment under this article. We aim to create a growing committed group of actors in this topic around BlueCity and would like to connect with best (and worst) practices in other parts of the Netherlands too.