Throughout history, underutilised plots of land have been repurposed into gardens – for instance for recreational purposes, for aesthetic reasons, but also for harvesting food or medical products like herbs. The practice of turning fallow land into gardens also presents valuable opportunities for sustainable urban development and public spaces. Typically, gardening activities take place on private grounds by the respective owners/legal tenants or – if on public land – are formally authorised and planned, e.g. through stakeholders such as municipal stakeholders. However, some take a more subversive approach through “guerilla gardening” – the act of greening spaces without legal ownership or consent. The different motivations for guerilla gardening range from improving the quality of life in the neighbourhood by creating climate-resilient spaces and providing food to a community in need to protest against on-going land-use policies and fighting “wasted opportunities”. From the early days of guerilla gardening to the contemporary context, this article explores the motivations behind this subversive practice, culminating in a case study of the Horta da Bananeira in Porto.
The Beginnings of a Global Movement
The first celebrated people to engage in the activity to appropriate land that was not theirs for gardening include Gerrard Winstanley with the agrarian socialist group “The Diggers” (or: “True Levellers”) in 1649 in England . Regarding the earth as “common treasury” , they cultivated public land in order to promote their political claim to restructure land ownership. Likewise, nurseryman Johnny “Appleseed” Chapman is considered a guerilla gardening pioneer who, in the beginning of the 19th century, introduced apple trees to several states in the US by selecting pieces of land just outside different towns, fencing them and opening nurseries there . Winstenley’s and Chapman’s activities were taking place in rather rural contexts where land was generally quite available and the people were more familiar with gardening activities than in the urban realm.
The term “urban guerilla gardening” was only introduced in the early 1970’s to describe Elizabeth Christy’s and the Green Guerillas’ activities [4, 5]. Christy was the first New Yorker to envision and realise a little park in one of the many vacant lots owned by the city in New York’s then deprived East Village. The collective Green Guerillas was founded by Christy – and is still active today in providing more New Yorkers with access to gardens and opportunities to grow their own vegetables and fruits. While in the 1970s, the collective followed transgressive patterns by throwing so-called seed bombs (mixture of clay, compost, water and plant seeds) to fenced and abandoned or neglected plots, they are today engaged in rather “formal” activities like education programs and the encouragement of communities for urban gardening in general. This is also because the city authorities responded quickly to the guerilla appropriation of the East Village plot in 1974 by offering a lease to the Green Guerillas for just $1 per month. This move effectively made it the first community garden in NYC to gain approval from the municipality. Soon after, many other community gardens started to implement the same payment strategy and they started popping up all over the city. 
Liz Christy (Photo by Jack Clarity)
Notwithstanding, there is a multiplicity in history and motives of guerilla gardening. For instance, another guerilla gardening movement emerged in Germany, in the context of 1970’s Turkish Gastarbeiter (immigrant workers) appropriating empty lots, having no garden of their own, to grow pole beans and other familiar vegetables from their homeland . In that case, the guerilla gardening was an important means to feel at least a bit at home in a strange country.
Another well-known guerilla gardener is Ron Finley and the LA Green Grounds with a guerilla garden project that he started in 2010 in South Central Los Angeles, a part of the city that is considered a so-called food desert. Food deserts describe certain regions or urban neighbourhoods that are affected by a lack of accessibility of healthy fresh food, resulting in diabetes, obesity and other malnutrition diseases . With his garden and educational practices, Finley encourages other people to engage in growing their own vegetables so that they can feed their children fresh produce.
The Effects of Guerilla Gardens
Generally, urban guerilla gardening has sprouted as an answer to the increasing number of people living in cities who lack access to land and green areas. Summarising the variety of motivations, guerilla gardening can be interpreted as a battle for resources, a fight against land scarcity but also a protest in opposition to environmental abuse. Within, the fight against wasted possibilities and towards beautifying spaces can be identified.
It is worth highlighting, though, that guerilla gardeners cannot be defined as a homogenous group of people. Even within certain organisations, different members might have their own personal motive forces for their gardening actions. While the motivations tend to vary, there is an intersection of effects that often emerge from guerilla gardens. The effects can be located on different scales: from individual to collective, from neighbourhood or block scale to global, from grassroots initiative to municipal administration. Four common effects will be highlighted in the following.
Guerilla gardening oftentimes contributes to increase urban productivity through local food production. Growing food can be out of necessity, a wish of self-sufficiency or an activism accomplishment. For instance, the Zapatistas movement in Mexico, the Tacamiches in Honduras or the Movement of Landless Rural Workers in Brazil are all examples of informal food production initiatives driven by necessity. The battle for food is not restricted to massive campaign initiatives or populous groups, there are numerous stories of very successful individuals. Initiating factors behind guerilla gardening movements focusing on food production can be traced to poverty caused by unemployment and political injustice or rising prices. Ron Finley, the guerilla gardener from Los Angeles, famously asserts that “growing your own food is like printing your own money.”
Furthermore, in the context of many western cities, the idea of self sufficiency and the residents’ wish to know more about the fruit and vegetables they consume is becoming quite popular, serving as another momentum for urban gardening initiatives. The wish of easier access to healthy grown produce and of detaching from large supermarket chains are frequent goals within contemporary urban communities. In an effort to boycott industrial agrobusiness, guerilla gardening projects are initiated in the name of ecological and political aspects.
In urban ecosystems, manifold issues and challenges can be tackled with greening and gardening interventions: Firstly, fallow land in its typical, dry and contaminated form has little carbon sequestration possibilities. Planting a variety of plants or even grass can help capture CO2. Secondly, the often polluted air in traffic-dense urban areas is cleansed through plants that can act as an efficient urban pollutant filter by binding the nitrogen dioxide (NO2) and particulate matter on their leaves . Thirdly, greening spaces contribute to the reconnection of potentially isolated habitats that are quite common in urban contexts. In doing so, they fulfill an important role in the conservation and promotion of biodiversity.
In times when scarce land in cities is sold to private developers at high prices, more and more places of consumption are emerging by private developers – shopping malls, cafés, co-working spaces, gyms. In those places, the wealthy people gather, while those who can not afford the respective services tend to dwell elsewhere. Low-threshold public places without compulsory consumption and admission, on the other hand, are becoming scarce. Against this backdrop, a common call is rising in many cities, demanding public places that are accessible at all times and to all, so that people of different backgrounds can mingle. This call for recreational community spaces also contributes to the development of guerilla greening interventions. Beautifying the neighbourhood as a joint project of residents can be a bonding moment for them and lead to convivial encounters amongst people who otherwise, without a shared goal, would not get to interact with or meet each other. Gardening is furthermore an activity that people can engage in without special skills or previous knowledge.
In the process of making use of a space that looks like it was forgotten, citizens, gardeners or neighbors become activists. Therewith, the guerilla gardeners are stakeholders that can no longer be forgotten when discussing the developments of the area that the garden is located in. By individuals joining forces, the gardeners increase their chances of getting a seat at the table, when the area they use is discussed in terms of development plans. So, the phenomenon of taking responsibility and planting over abandoned areas in urban contexts can be interpreted as an effort towards co-designing the city.
A rather involuntary side effect of guerilla gardening that cannot be forgotten is its contribution to gentrification. Enhancing the aesthetic appeal of an underutilised space can have a ripple effect, improving the value of the surrounding area and potentially attracting the attention of real estate developers. This is referred to as green gentrification or eco-gentrification . Such process evolves into a threat for the transformed space which might be dismantled to develop more economically profitable urban elements.
Political / Administrative Responses
It can be said that the “formalisation” as in the case of the Liz Christy Community Garden is quite typical for today’s developments: many of the guerilla gardens are eventually legalised by the municipal authority buying the land and then formally leasing it to the community, oftentimes for a symbolic price or through public money that keeps these projects alive by paying the lease of private lands. Oftentimes, the ecological transformation or the “beautifying” within the gardening projects are in line with the city’s development plans in certain neighbourhoods. The guerilla gardening movement grew out of citizens’ frustration with municipal financial neglect and disinvestment. Interestingly, this protest movement is slowly declining in popularity, while municipally-supported community gardens in urban areas are becoming increasingly popular.
Oftentimes, formalising guerilla gardens by the authorities goes hand in hand with certain obligations or interests by the public stakeholders, risking to change the grassroots and self-organised character of the gardens. However, these formalisation processes as well can be relieving to the guerilla gardening groups, since many of them have fought their battles with maintaining or defending their space towards private real estate developers. One of the main drivers of guerilla gardening projects is the protest to land use practices or to fight for change, especially when the land was left lying fallow for many years before. In entering a partnership or formalisation process of productively gardening on a piece of land that had been neglected with public authorities, this change occurs. Consequently, a formalisation can be seen as a success.
Case Study: Horta Comunitária da Bananeira in Porto
The Horta da Bananeira is another famous example of guerilla gardening. Located on the steep slope in Porto’s central neighbourhood Fontaínhas in the Freguesia do Bonfim, framed by rocks and train tracks, the area of the garden expands over a stretch of roughly 300m. A typical lavadouro publico (communal washing points), as known from Portuguese villages or urban ilhas, forms the entrée to the garden from Alameda das Fontaínhas (upper entrance). It can also be accessed from “below”, from the Avenida Gustavo Eiffel. The gardens are visible from the Douro and Gaia’s riverside. Most of the plot’s land is owned by the Camara Municipal.
Comparative view on the area of the Horta da Bananeira (left photo by Nuno Morão – Urbano 15518, Porto, 2010.04.24)
The Horta project is quite young, as the land has for a long time been used for housing. The steep topography resulted in a landslide in 2001, destroying some of the houses. Over a decade later, in 2015, the 13 families that still resided here were relocated to council housing elsewhere and the houses were demolished. For five years, the plot was left to itself – and informally used as a garbage dump. It was initially appropriated by a group of locals in May 2020, in the beginning of the Covid-19 pandemic. They cleaned up the space, in order to decontaminate and cure the soil so that plants could be cultivated. However, this group of people had not initially planned on sticking to the project for a long time. What they were aiming for was rather an activation of the plot that would invite other people to continue with the gardening process. Since then, the community garden “[…] aims to promote the community and active participation of people in the requalification of urban space, the accountability of citizens in the direct care of the land and the development of egalitarian and horizontal social dynamics”. 
Today, the garden has an extremely high level of biodiversity, proving once again that any urban wasteland, no matter how contaminated, is suitable for guerilla gardening. On the site visit, fig trees, palm trees, herbs like rosemary, mint or thyme, beds with strawberries, lettuce, spring onions or cabbage could be found. Gardeners lovingly built climbing aids for vines, peas and other tendrils. Some areas of the garden are more structured than others. Some used small fences to protect their beds from dogs or to mark the area where they garden. Other parts of the garden are rather wild. For instance, large areas outside the different garden “plots”, towards lower levels of the garden, are covered in grass and nasturtium. The ruins left over from the time of residential use on the site structure the garden in a meaningful way. Stairs connect the different terraces, which are roughly divided into three levels. Footpaths run through the site and provide access down to the douro riverbank. This ensures sufficient sunshine in all the beds. Water supply is also ensured: a fountain, relatively far up in the community garden, offers the possibility to fill watering cans. Likewise, a carefully laid network of water hoses runs from there through the gardens. Here and there in the garden you can also find objects that can be used and shared by the public. For example, there are a number of self-made seating arrangements that also invite the public to relax in the garden and enjoy the great views.
Nowadays, the Horta da Bananeira is only loosely – if at all – organised. There was no contact person to reach out to and it seems like whoever wants to garden there, just goes and appropriates unused parts and starts planting. At some point in time, “seed banks” were built, where the gardeners were invited to exchange seeds. These wooden shelves were overgrown and empty at the time of the site visit. This gives the impression that the spirit that once drove a group of people to actively make use of this unused plot is sort of gradually dissolving into more individual gardening.
The practices of the Bananeira gardeners, both the initial guerilla gardeners but also the people who are active there nowadays, can be interpreted as a political act: the face of Porto as a city is currently characterised by numerous abandoned buildings and plots of land – an issue that municipal actors and policy makers do not really act upon. Vacancy can have negative effects, like impoverishment and divestment. At the same time, rents have been skyrocketing so that Porto’s residents are either pushed out of the centre or have to give in to rents that they actually cannot afford. Furthermore, tourism has become an important economic pillar of the city, leading to more and more services, businesses and apartments catering to tourists. The practice of “squatting” a central location on the Douro riverside with sunset views can be seen as a subtle Right to the City  act, where gardeners also claim their slice of the pie. But as has been stated before, the motivations to do urban gardening can as well be pure necessity for food or the will to find some balance to the stressful everyday life through gardening.
Conclusion: Self-efficacy through gardening practices
An increasing global and specifically urban population together with exploitation pressure weighing on urban land are stressing the available land as a finite resource to satisfy human needs. Unequal distribution of land, with few people owning large areas of land, worsens the land scarcity issue for many. If all the cultivated land in the world would be reassigned equally there would be half an acre per person and when including uncultivated land (without Antarctica) the number would reach up to 5 acres per individual. The fact that most people are far from owning / being able to cultivate 5 acres gives a feeling of injustice. Cities play an important role in the uneven use of land since more than half of the world population live in urban settings. Coexisting densely in spaces is considered efficient and sustainable in many ways, however, it often comes at a high cost for gardening and opportunities to cultivate.
This scarcity of land motivates guerilla gardeners who want to prove wrong the idea of cities being garden-scarce spaces and spaces where the way that land is used is dictated through money flows. Land is not distributed based on needs but as an economic asset which causes the presence of many neglected pieces of land, since revenue is not only linked with usage. Neglected spaces are the main targets and starting places for guerilla gardeners.
By appropriating a neglected piece of land, gardeners experience a large degree of self-efficacy. They see the transition of a seemingly dead soil or unnoticed pieces of land turning into oasis that provide fruit, herbs and vegetables, low-threshold spaces for the people to relax and hang out, important educational hubs, etc. The spatial manifestation of their own hands, pro-activeness and courage is a large accomplishment that empowers their sense of being able to shape the urban environment they live in according to their needs. It also has to potential to give them a reputation in the neighbourhood which might later on – i.e. at a point where the land they appropriated is at stake – be useful.
 Working Class Movement Library. n.d. ‘Gerrard Winstanley and the English Diggers’. WCML. Accessed 9 March 2023. https://www.wcml.org.uk/our-collections/protest-politics-and-campaigning-for-change/gerrard-winstanley-and-the-english-diggers/;
 Plant, David. 2014. ‘Diggers or True Levellers’. 3 March 2014. http://bcw-project.org/church-and-state/sects-and-factions/diggers.
 Wills, Matthew. 2016. ‘The Real Story Behind “Johnny Appleseed”’. JSTOR Daily (blog). 22 October 2016. https://daily.jstor.org/the-real-story-behind-johnny-appleseed/.
 Wilson, Peter Lamborn, and Bill Weinberg, eds. 1999. Avant Gardening: Ecological Struggle in the City and the World. Brooklyn, NY: Autonomedia.
 Loggins, Donald. 2007. ‘Garden History’. 2007. http://lizchristygarden.us/.
 Vox. 2021. How Radical Gardeners Took Back New York City. Vol. Missing Chapter. Vox. https://www.youtube.com/watch?v=_g2CaF12xxw&t=721s.
 Baier, Andrea, Christa Müller, and Karin Werner. 2013. Stadt der Commonisten: Neue urbane Räume des Do it yourself. 1st ed. Urban Studies. Bielefeld, Germany: transcript Verlag. https://doi.org/10.14361/9783839423677.
 Kelli, Heval M., Jeong Hwan Kim, Ayman Samman Tahhan, Chang Liu, Yi‐An Ko, Muhammad Hammadah, Samaah Sullivan, et al. 2019. ‘Living in Food Deserts and Adverse Cardiovascular Outcomes in Patients With Cardiovascular Disease’. Journal of the American Heart Association 8 (4): e010694. https://doi.org/10.1161/JAHA.118.010694.
 Pugh, Thomas A. M., A. Robert MacKenzie, J. Duncan Whyatt, and C. Nicholas Hewitt. 2012. ‘Effectiveness of Green Infrastructure for Improvement of Air Quality in Urban Street Canyons’. Environmental Science & Technology 46 (14): 7692–99. https://doi.org/10.1021/es300826w.
 Hawes, Jason K, Dimitrios Gounaridis, and Joshua P Newell. 2022. ‘Does Urban Agriculture Lead to Gentrification?’ Landscape and Urban Planning 225 (September): 104447. https://doi.org/10.1016/j.landurbplan.2022.104447.
 n.a. n.d. ‘Perguntas e Repostas’. Accessed 9 March 2023. https://hortadabananeira.hotglue.me/.
 Lefebvre, Henri. 1968. Le Droit à La Ville. Paris: Anthopos.