“We grow food here that is quite expensive in the supermarket,” says 36-year-old Maribel Lopez from Poblenou’s urban garden with its large, inviting gate and neat signage in Barcelona’s hippest neighbourhood on the east side of the city. 

“This neighbourhood used to have a ghetto vibe before. Now, over the past two decades, it has changed. There is a really nice community and loads of cultural events. We have several urban gardens. Some have popped up, and some are managed with the help of the city government. Some people I know are members of several gardens and participate in seed exchanges. Some are also involved in guerrilla gardening.”

“The value here is the process, the commitment, and for sure the distraction from everyday problems.”

Lopez explains that people come here to spend time during their lunch breaks, read a book, and enjoy time with their families and friends. “Growing food together and taking care of the plants, doing something with someone who you maybe wouldn’t have otherwise met is what brings community to this space,” she continues. “Here, we can learn and teach different skills, not only in relation to gardening but also about nutrition and upcycling. I joined to be closer to nature and my community. There is no greater joy than harvesting your own tomato, someone said. Well, I think it is an even better experience when you share this joy.” 

Lopez shows me different beds and what is being grown there. “Of course, not everything works out. We have had our fair share of plants dying,” she laughs. “I think the value here is the process, the commitment, and for sure the distraction from everyday problems, the horrors of the world, and long working hours.” Maribel explains that each urban garden collective decides on its structure, workload, and food distribution: some donate the harvest to those in need, some share everything among members.

Last summer it was often unbearably hot, and urban gardens were looked at as refuges from the heat even though they have few trees. “This neighbourhood does not have big parks. People have to go quite a distance for them or to the crowded beach to cool down. Urban gardens are mostly managed as temporary infrastructure; growing tall trees that provide a lot of shade is quite difficult,” says Lopez. In my home country, Georgia, a cradle of winemaking, grapevines are often planted around kheivani, a type of trellis, which offers both delicious fruit and shade. Could similar solutions help Barcelona and other cities in the hot season by making up for the scarcity of trees?

As I leave the garden in Poblenou, I think of everything Lopez has told me, and wonder whether urban and guerrilla gardening can be an effective strategy to collectively organise around the impacts of the climate crisis. 

Greening urban heat islands

Cities contribute significantly to climate change and are heavily affected by its impacts. According to the Intergovernmental Panel on Climate Change (IPCC), urbanisation increases annual surface air temperature in cities and their surroundings, and this urban heat island (UHI) effect makes heatwaves more intense, particularly at night.¹

Barcelona and the broader Catalonia region have been hit hard by warming temperatures and other climate impacts. The Catalan capital has been suffering from drought for more than two years. In February 2024, the city of Barcelona introduced a water-saving regime. Posters on public transport and all over the city warned inhabitants about the water shortage and empty reservoirs, and advocated an individual 200-litres-per-day limit. The government invested around 500 million euros in water desalinators to tackle the immediate problem. However, desalination is very energyintensive and produces brine waste and toxic chemicals that negatively affect marine life in local bays. 

City planners and governments need to take urgent action as matters get worse in urban spaces the world over. According to research carried out in Mexico City, transport infrastructure, especially roads, contributes significantly to UHI. Urban canyons of concrete and glass also add to cities heating up. In the longer term, shifting towards more eco-friendly construction materials and building a sustainable transport infrastructure are some of the strategies that could help Barcelona and similar cities adapt to the climate crisis.

City planners and governments need to take urgent action as matters get worse in urban spaces the world over.

Another strategy is re-greening. Unlike demolishing a skyscraper, planting trees and developing urban gardens takes significantly fewer resources. Introducing diverse flora, such as wildflowers, shrubs, and grasses ensures that moisture from the soil evaporates more slowly. Applying the principles of permaculture to build self-feeding systems contributes to urban water preservation and air quality improvement. Instead of a few square-metre areas containing only one plant species, permaculture advocates the benefits of planting different species. This method also minimises the efforts required to maintain a garden or green area. The climate crisis could be significantly mitigated if cities maximised the available space for growing beneficial plants, be it for food, pollination, or improving the soil, instead of keeping green lawns or covering areas with asphalt and concrete.

Environmentalism vs tourism

“The city of Barcelona has experienced great changes in its urbanisation over the last couple of decades,” says Quique Gornés. As a civil engineer and member of the left-wing Barcelona en Comú party, Gornés became chief of staff of the Council for Climate Emergency and Ecological Transition between 2019 and 2023 during the second mayoral term of Ada Colau, a former housing rights activist. He was responsible for urban services, such as water, waste, renewable energy, green area management, and biodiversity in the city, as well as the climate emergency and its mitigation.

Once Spain had been restored as a democracy in the late 1970s, Catalonia’s capital was transformed into a large, service-driven city concentrating on tourism. From the impetus of the 1992 Olympic Games until well into the 2000s, Barcelona’s urbanisation followed the criteria of architectural beauty, functionality, or maintaining efficiency. 

Cars circulated at the expense of green areas. Some symbolic actions were carried out in that period to reduce the presence of cars, such as the pedestrianisation of Avinguda del Portal de l’Àngel and the centre of the Vila de Gràcia neighbourhood, but these were actions favouring commerce rather than the reduction of emissions. “The economic crisis from 2011 to 2015 caused the right-wing government to bet on the city becoming a major tourist destination once again,” says Gornés. 

When Ada Colau became Barcelona’s mayor in 2015, the fight to establish government action in response to the climate emergency became central. Barcelona Energia, the city’s first municipal public electricity company, was created in 2018, supplying Barcelona City Council and more than 5000 families and companies with renewable energy. The city government also adopted the Climate Emergency Plan, and started transforming towards a Doughnut economic model and implementing a sustainable urban drainage system.

“Unfortunately, we did not quite manage to recover public ownership of the water supply company,” says Gornés with regret. “The metropolitan region of Barcelona consumes almost 300 million cubic metres of water in a normal year – even without a drought. The number of tourists is growing year on year, putting additional pressure on the city and the region as a whole. In my opinion, the posters that are in public places should be put in each hotel room and lobby.”

On a more positive note, Gornés attests to the “almost 90 hectares of urban land that were transformed into green areas during Colau’s eight-year mayorship. And the strategy for the increase and improvement of green areas by 2030 was approved.”

Barcelona already has approximately 360 urban gardens. Some are supported by Barcelona City Council. From school-yard projects for children to a special gardening programme established at the end of 1990s for senior citizens, the city has put a lot of effort into connecting generations and supporting biodiversity. Recent urban renewal projects, for example in Avinguda Meridiana and Passeig de Sant Joan, also enrich the streets: not only trees and grass but also flowers, grasses, and shrubs are now growing alongside pavements in these areas.

But there is still plenty of room for improvement. Like many cities, Barcelona has a significant amount of unused land: abandoned yards, empty patches of earth on streets, huge spaces in between buildings in so-called “sleeping districts”. Even the lawns around classic nuclear family homes could be put to better use. All this soil has great latent potential.

DIY exteriors

A Catalan gardening activist, who prefers to remain anonymous, explains to me that guerrilla gardening, like urban gardening, is not as complex as it might seem. They tell me about who they garden with and how they organise themselves: “We chat on Signal. It is mostly Catalan people. We do seasonal, evening actions. Sometimes we prepare seed bombs, sometimes we use seedlings from our own homes or urban gardens instead and throw them here and there. We always try to put several plants under one tree rather than one plant here and one plant there. Trying to do permaculture in a little square surrounded by concrete is difficult, but it is better than nothing.”

The activist, who studied botany at university, decided to apply their knowledge on a political and social level in the city. “There should be more radical and decentralised action,” they say. “Everyone could be doing more – much more.”

I want to have a list of takeaways and recommendations for guerrilla gardening. The activist gives me tips on how to get started:

• Make your group – you can be as few as four people as long as you are consistent; 

• Create a safe communication channel for discussing your first action; 

• Decide where you want to plant – best is somewhere nearby. Make sure there are no potential disruptions (police patrols, inquisitive neighbours, revellers from loud party venues or bars – anyone that you do not want to encounter while doing your action). You can skip this step if you work with seed bombs. Look for the spaces around trees, empty patches, and even private properties (for seed bombs); 

• Choose and prepare your plants and tools; 

• Plant. Always make sure to have two people watching the street – this really depends on where you live and how much the police and other people care about what you do. Some decide to do it during the day and wear “uniforms” so they are not bothered by passers-by; 

• Keep an eye on the plants afterwards – check on them every once in a while. 

“I wish more people were urban and guerrilla gardeners,” the activist adds. “I am a member of many collectives now and constantly see people having their lives changed through these activities. Even growing a flower on your balcony can be beneficial. Perhaps we cannot tackle climate change with this alone, but we can for sure have a more socially connected, pleasant, and nutritious environment in our cities.” 

Hands-on re-greening

Years ago, I felt inspired and decided to start experimenting with urban gardening by greening my balcony. Poblenou’s Maribel Lopez and the guerrilla gardening activist I spoke to were right when they said greening spaces is easier than people think. After learning some basics and experimenting, I achieved the results I wanted. Those with access to the internet can tap into urban and guerrilla gardening examples from all over the world, get educated, and share experiences. You might not aspire to produce all the food you consume or want to spend your time in urban gardens, but even planting some flowers and setting up a wild bee hotel on your balcony – if you are lucky enough to have one – can make a difference.

If everyone makes their surroundings as green as they can, the overall urban ecological environment will be much improved. Of course, voting and other types of participation on a city level as well as other eco-friendly practices are important, but urban and guerrilla gardening are two of the easiest methods to contribute to improving the life and climate of the city you live in.

In almost every district of Barcelona, I see areas covered with yellow, burnt patches of grass or vacant lots covered with concrete. Even though many balconies and terraces feature decorative plants, satellite imagery shows that green roofs are practically absent. As yet, there is no proof that urban gardening would be efficient on a massive scale. A city that has urban gardens in all available spaces – excluding rooftops used for other, vital purposes such as energy production from solar panels – is needed as a study example. But existing urban horticulture projects in many cities, regions, and countries already show that they can be at least a partial solution to food insecurity and food deserts.

After living in Barcelona, where everyone is happy when they see rain, I had the feeling that with time it will also become more and more crucial for people to grow their own food. Individuals, schools, collectives, communities, and families growing for themselves can empower themselves, others, and the planet. Urban activism in its various expressions has always been at the forefront of critical struggle, and now communities are building their collective and economic power through gardening.

Maribel Lopez and other urban and guerrilla gardeners are trying to achieve greater independence across Barcelona. Permaculture, green roofs, and other green infrastructure may come at a financial cost, but in the long run, the benefits are immense. And this investment is not just a tool to improve the life of urban residents but also a way to mitigate the effects of climate change.

1. The IPCC reports that urbanisation increases temperatures from 0.19 to 2.6°C, that UHI raises temperatures by 1.22-4°C, and that “there is a well established relationship between extremely high temperatures and mortality”. ↩︎