Urban farmers are learning to grow food without soil or natural light

Hydroponics at work. Image: Getty.

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 $6.9bn 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.

They grow up so fast. Image: 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.

A simplified hydroponic frame in Portsmouth. Image: Silvio Caputo/University of Portsmouth/author provided.

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.

The ConversationAs 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, Senior Lecturer, University of Portsmouth.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

Green roofs improve cities – so why don’t all buildings have them?

The green roof at the Kennedy Centre, Washington DC. Image: Getty.

Rooftops covered with grass, vegetable gardens and lush foliage are now a common sight in many cities around the world. More and more private companies and city authorities are investing in green roofs, drawn to their wide-ranging benefits which include savings on energy costs, mitigating the risk from floods, creating habitats for urban wildlife, tackling air pollution and urban heat and even producing food.

A recent report in the UK suggested that the green roof market there is expanding at a rate of 17 per cent each year. The world’s largest rooftop farm will open in Paris in 2020, superseding similar schemes in New York City and Chicago. Stuttgart, in Germany, is thought of as “the green roof capital of Europe”, while Singapore is even installing green roofs on buses.

These increasingly radical urban designs can help cities adapt to the monumental challenges they face, such as access to resources and a lack of green space due to development. But buy-in from city authorities, businesses and other institutions is crucial to ensuring their success – as is research investigating different options to suit the variety of rooftop spaces found in cities.

A growing trend

The UK is relatively new to developing green roofs, and governments and institutions are playing a major role in spreading the practice. London is home to much of the UK’s green roof market, mainly due to forward-thinking policies such as the 2008 London Plan, which paved the way to more than double the area of green roofs in the capital.

Although London has led the way, there are now “living labs” at the Universities of Sheffield and Salford which are helping to establish the precedent elsewhere. The IGNITION project – led by the Greater Manchester Combined Authority – involves the development of a living lab at the University of Salford, with the aim of uncovering ways to convince developers and investors to adopt green roofs.

Ongoing research is showcasing how green roofs can integrate with living walls and sustainable drainage systems on the ground, such as street trees, to better manage water and make the built environment more sustainable.

Research is also demonstrating the social value of green roofs. Doctors are increasingly prescribing time spent gardening outdoors for patients dealiong with anxiety and depression. And research has found that access to even the most basic green spaces can provide a better quality of life for dementia sufferers and help prevent obesity.

An edible roof at Fenway Park, stadium of the Boston Red Sox. Image: Michael Hardman/author provided.

In North America, green roofs have become mainstream, with a wide array of expansive, accessible and food-producing roofs installed in buildings. Again, city leaders and authorities have helped push the movement forward – only recently, San Francisco created a policy requiring new buildings to have green roofs. Toronto has policies dating from the 1990s, encouraging the development of urban farms on rooftops.

These countries also benefit from having newer buildings, which make it easier to install green roofs. Being able to store and distribute water right across the rooftop is crucial to maintaining the plants on any green roof – especially on “edible roofs” which farm fruit and vegetables. And it’s much easier to create this capacity in newer buildings, which can typically hold greater weight, than retro-fit old ones. Having a stronger roof also makes it easier to grow a greater variety of plants, since the soil can be deeper.


The new normal?

For green roofs to become the norm for new developments, there needs to be buy-in from public authorities and private actors. Those responsible for maintaining buildings may have to acquire new skills, such as landscaping, and in some cases volunteers may be needed to help out. Other considerations include installing drainage paths, meeting health and safety requirements and perhaps allowing access for the public, as well as planning restrictions and disruption from regular ativities in and around the buildings during installation.

To convince investors and developers that installing green roofs is worthwhile, economic arguments are still the most important. The term “natural capital” has been developed to explain the economic value of nature; for example, measuring the money saved by installing natural solutions to protect against flood damage, adapt to climate change or help people lead healthier and happier lives.

As the expertise about green roofs grows, official standards have been developed to ensure that they are designed, built and maintained properly, and function well. Improvements in the science and technology underpinning green roof development have also led to new variations on the concept.

For example, “blue roofs” increase the capacity of buildings to hold water over longer periods of time, rather than drain away quickly – crucial in times of heavier rainfall. There are also combinations of green roofs with solar panels, and “brown roofs” which are wilder in nature and maximise biodiversity.

If the trend continues, it could create new jobs and a more vibrant and sustainable local food economy – alongside many other benefits. There are still barriers to overcome, but the evidence so far indicates that green roofs have the potential to transform cities and help them function sustainably long into the future. The success stories need to be studied and replicated elsewhere, to make green, blue, brown and food-producing roofs the norm in cities around the world.

Michael Hardman, Senior Lecturer in Urban Geography, University of Salford and Nick Davies, Research Fellow, University of Salford.

This article is republished from The Conversation under a Creative Commons license. Read the original article.