How urban farmers are learning to grow food without soil or natural light

Mandy Zammit/Grow Up, Author Provided

This guest blog was written by Silvio Caputo, Senior Lecturer in the School of Architecture, University of Portsmouth.

Growing food in cities became popular in Europe and North America during and immediately after World War II. Urban farming provided citizens with food, at a time when resources were desperately scarce. In the decades that followed, parcels of land which had been given over to allotments and city farms were gradually taken up for urban development. But recently, there has been a renewed interest in urban farming – albeit for very different reasons than before.

As part of a recent research project investigating how urban farming is evolving across Europe, I found that in countries where growing food was embedded in the national culture, many people have started new food production projects. There was less uptake in countries such as Greece and Slovenia, where there was no tradition of urban farming. Yet a few community projects had recently been started in those places too.

Today’s urban farmers don’t just grow food to eat; they also see urban agriculture as a way of increasing the diversity of plants and animals in the city, bringing people from different backgrounds and age groups together, improving mental and physical health and regenerating derelict neighbourhoods.

Many new urban farming projects still struggle to find suitable green spaces. But people are finding inventive solutions; growing food in skips or on rooftops, on sites that are only temporarily free, or on raised beds in abandoned industrial yards. Growers are even using technologies such as hydroponics, aquaculture and aquaponics to make the most of unoccupied spaces.

Something fishy

Hydroponic systems were engineered as a highly space and resource efficient form of farming. Today, they represent a considerable source of industrially grown produce; one estimate suggests that, in 2016, the hydroponic vegetable market was worth about US$6.9 billion worldwide.

Hydroponics enable people to grow food without soil and natural light, using blocks of porous material where the plants’ roots grow, and artificial lighting such as low-energy LED. A study on lettuce production found that although hydroponic crops require significantly more energy than conventionally grown food, they also use less water and have considerably higher yields.

Growing hydroponic crops usually requires sophisticated technology, specialist skills and expensive equipment. But simplified versions can be affordable and easy to use.

Mandy Zammit/Grow Up, Author Provided

Hemmaodlat is an organisation based in Malmö, in a neighbourhood primarily occupied by low-income groups and immigrants. The area is densely built, and there’s no green space available to grow food locally. Plus, the Swedish summer is short and not always ideal for growing crops. Instead, the organisation aims to promote hydroponic systems among local communities, as a way to grow fresh food using low-cost equipment.

The Bristol Fish Project is a community-supported aquaponics farm, which breeds fish and uses the organic waste they produce to fertilise plants grown hydroponically. GrowUp is another aquaponics venture located in an East London warehouse – they grow food and farm fish using only artificial light. Similarly, Growing Underground is an enterprise that produces crops in tunnels, which were originally built as air raid shelters during World War II in London.

The next big thing?

The potential to grow food in small spaces, under any environmental conditions, are certainly big advantages in an urban context. But these technologies also mean that the time spent outdoors, weathering the natural cycles of the seasons, is lost. Also, hydroponic systems require nutrients that are often synthesised chemically – although organic nutrients are now becoming available. Many urban farmers grow their food following organic principles, partly because the excessive use of chemical fertilisers is damaging soil fertility and polluting groundwater.

To see whether these drawbacks would put urban growers off using hydroponic systems, my colleagues and I conducted a pilot study in Portsmouth. We installed small hydroponic units in two local community gardens, and interviewed volunteers and visitors to the gardens. Many of the people we spoke to were well informed about hydroponic technology, and knew that some of the vegetables sold in supermarkets today are produced with this system.

Many were fascinated by the idea of growing food without soil within their community projects, but at the same time reluctant to consume the produce because of the chemical nutrients used. A few interviewees were also uncomfortable with the idea that the food was not grown naturally. We intend to repeat this experiment in the near future, to see how public opinion changes over time.

And while we don’t think hydroponic systems can replace the enjoyment that growing food in soil can offer, they can save water and produce safe food, either indoors or outdoors, in a world with increasingly scarce resources. Learning to use these new technologies, and integrating them into existing projects, can only help to grow even more sustainable food.

As with many technological advancements, it could be that a period of slow acceptance will be followed by rapid, widespread uptake. Perhaps the fact that IKEA is selling portable hydroponic units, while hydroponic cabinets are on the market as components of kitchen systems, is a sign that this technology is primed to enter mainstream use.

Silvio Caputo is Senior Lecturer in the School of Architecture, University of Portsmouth.

This article was originally published on The Conversation website and has been republished with permission under a Creative Commons licence. Read the original article.

If you enjoyed this blog, why not read some of our other blogs:

ReGen Villages: is this the future of sustainable living? 


‘Illustration © EFFEKT’

The Netherlands covers an area of 41,543 km², and has a population of 17 million people. That works out at 488 people per square kilometre, making Holland the most densely populated country in the European Union. By comparison, the UK has a population density of 413 people per sq km, while the figure for Scotland is just 68 people per sq km

Statistics like that matter when it comes to waste management. Lack of space in the Netherlands has prompted successive governments to divert waste from landfill, and encourage more recycling. The waste management movement was strongly influenced by Ad Lansink, a chemistry lecturer turned politician, who developed “Lansink’s Ladder”. This tool has six “rungs”, with disposal on the bottom, then recovery, recycling, reuse and on the top rung prevention.

The Dutch approach has reaped impressive benefits, with high rates of recycling and most of the remainder being incinerated to generate electricity and heat.

However, there is a growing sense that recycling in the Netherlands may be close to its limit. In 2015, Green Growth in the Netherlands reported that since 2000, the percentage of recycled waste has remained more or less constant.

“Recycled material reached 81% in 2012, a high share that has been fairly constant over the years. This may indicate that the recycling percentages are close to their achievable maximum.”

The Dutch are now looking for further ways to create more value from recycled waste.

ReGen Villages

One such idea is the development of  “regenerative villages” (ReGen). These self-reliant communities will produce their own food, generate their own energy and recycle their own waste.

The ReGen model is the brainchild of California-based ReGen Villages, which is partnering with EFFEKT, a Danish architecture practice, to launch a pilot version in the Netherlands this year. 

Each ReGen community will contain a variety of homes, greenhouses and public buildings, with built-in sustainable features, such as solar power, communal fruit and vegetable gardens and shared water and waste management systems.  The five principles underpinning the concept are:

  • energy positive homes,
  • door-step high-yield organic food production,
  • mixed renewable energy and storage,
  • water and waste recycling,
  • empowerment of local communities

The first 25 pilot prefabricated homes will be located at Almere in the west of Holland. Almere has experienced exponential growth, rising from farmland in the 1970s to become the seventh largest city in the Netherlands.

Waste management is a key element in the ReGen villages, which will have  ‘closed-loop’ waste-to-resource systems that turn waste into energy.


‘Illustration © EFFEKT’

Prospects and problems

There are plans to roll out the model in other communities, in Europe, North America and the Middle East. Off-grid communities are not a new idea. But the necessary technology, falling costs and consumer demand have reached a point where the ReGen approach may become truly sustainable. The idea offers the promise of meeting the challenges of rising populations making unprecedented demands on limited resources.

Interviewed in The Guardian, Frank Suurenbroek, professor of urban transformation at the Amsterdam University of Applied Sciences, acknowledged the need for such projects, but also highlighted potential problems:

“A possible field of tension is how the technological demands of sustainability and circularity [interact with] spatial configurations needed to create attractive places and the desire to create new houses fast. Both worlds have to learn how to connect. Experiments with new sustainable quarters are interesting and needed, but a major issue is how to do this within existing built areas.”

All eyes on Almere

Once the first 25 homes are built, a further 75 will complete the village. It will take a lot of time, money, skill and muscle to make the project a success . We’ll be watching with interest to see if the vision can be turned into reality.

Our thanks to EFFEKT in Copenhagen for their permission to reproduce the images in this blog post.

If you’ve found this blog post interesting, you may also like our previous posts on recycling and the circular economy: