Join us in Ljubljana (Slovenia) at Krater on May 22nd for a Soil Assembly gathering at the Festivities under Siege conference (20-22 May).

Across three days, the feral grounds will bloom into a planetary garden of unruly kin: architects holding parks open through occupation, lawyers plotting paths toward nature’s liberation, artists dwelling in the neglected zones of administration, landscape architects guiding walks through the feral undergrowth, curators turning residencies into commons, tiger mosquitoes redrawing the city with their bites, and many others — all reclaiming the city and its many natures otherwise.

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Krater’s Soil Assembly: Unpaving the Urban Ground for Human–Soil Entanglements in Ljubljana
Date: 22 May 2026
Location: Krater, Ljubljana, Slovenia

Soil Assembly in Ljubljana holds a community of artists, researchers, ecologists, and local practitioners on Krater after two days of Festivities Under the Siege Conference to explore soil as a living commons through practical workshops, critical walks, lectures, organic surplus transformations and collective food experiments. Based in Krater, a transdisciplinary urban ecology laboratory and community space situated in a rewilded construction pit near the city centre, the programme is situated across a unique site dedicated to emergent regenerative practices, urban ecology, creativity and experimental forms of collective production.

Moving between discussions of extraction and celebration, the gathering approaches soil not as an inert resource, but as a dynamic living system shaped by microorganisms, plants, infrastructures, waste streams, and social cooperation. Through critical research of management and administration of urban soils, sonic listening walks, Bokashi composting, fertiliser-making from invasive Japanese knotweed, and shared meals, participants are invited to reclaim the urban space and engage with ecological maintenance as a collective civic right.

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Morning Programme: Soil Commons
The morning programme unfolds around the theme Soil Commons: Organic Surplus Transformations, Reciprocity, and Urban Food production, bringing participants together around communal practices of soil care, fermentation, and sustainable food production.

The day opens with a Bokashi composting workshop led by Andrej Koruza, introducing fermentation as a collaborative ecological process that transforms kitchen waste into living soil. Participants prepare Bokashi bran, build fermentation containers, and explore how fermented organic matter can support resilient food systems, vermicomposting, and no-dig gardening.

This is followed by a master thesis presentation by Enja Grabrijan exploring human relationships with soil ecosystems through questions of reciprocity, care, environmental perception, and the vitality of soil as a living entity embedded within microbial, geological, and social processes.

The morning concludes with a collective fertiliser-making workshop using invasive Japanese knotweed biomass. Participants harvest, shred, and ferment plant material to produce local organic fertiliser for urban food cultivation while reflecting on how ecological maintenance can become a shared urban practice.

 

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Afternoon Walk: The Earth: Stolen and Reclaimed x Sonic Acts of Noticing
In the afternoon, The Earth: Stolen and Reclaimed guides participants on a walk from Ljubljana’s central railway station to Krater through the layered political ecology of land and soil in the city.

Developed in collaboration with Sonic Acts of Noticing, The Earth: Stolen and Reclaimed is a walk exploring the political ecology behind the management and administration of soil and land in Ljubljana. From the central railway station — the site of the Emonika development, the case study at the heart of this research — to Krater, a reclaimed urban ecosystem, we trace the dynamics of systemic soil and land exploitation through practices of Deep Listening, using ambient microphones and geophones to attune to the city’s layered soundscapes. As a guided inquiry, the walk invites us to consider whether the struggle over land and extraction might well be the central question we must collectively address.

The walk is the culmination of a three-month-long site-specific mapping process, administrative digging, and critical research led by architects Tina Božak and Altan Jurca Avci, joined this time by Julia Udall’s sonic explorations.

 

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Evening Programme: Off the Books Tasting
The evening concludes with Off the Books Tasting, a participatory gathering by Aki Namba and Andrea Stevens from NOTNOT Atelier.

Off the Books Tasting is a participatory event that uses invasive/native taxonomy to reframe food, knowledge, and ecological histories. Through ingredient cards, shared reading, and light food offerings, participants will trace the colonial and political contexts embedded in what we eat, moving into collective discussion and reflection around classification, care, and shared sustenance.

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Programme Schedule

10:30 – 11:00 Registration & Coffee
11:00 – 11:10 Introduction to Soil Assembly
11:10 – 12:00 Bokashi Workshop
12:00 – 12:50 Hands in the Soil: Relationship to Soil with Regards to Care, Enja Grabrijan
12:50 – 13:00 Coffee Break
13:00 – 13:50 Japanese Knotweed Fertiliser Workshop
13:50 – 14:00 Morning Session Wrap-Up
14:00 – 15:00 Lunch
15:45 – 19:00 The Earth: Stolen and Reclaimed x Sonic Acts of Noticing
19:00 – 21:00 Off the Books Tasting by NOTNOT Atelier
The programme situates soil regeneration not only as an ecological process, but as a cultural, social, and political practice grounded in cooperation, maintenance, and shared responsibility toward more-than-human urban ecosystems.

About the participants:

NOTNOT Atelier is a collaboration between Andrea Steves and Aki Namba, working across performance, installation, and research-based practices. Their work explores food, ecology, and knowledge systems through participatory formats that blur art, pedagogy, and collective inquiry.

Tina Božak is an architect working across design and research. She completed her master’s degree at the Faculty of Architecture in Ljubljana with a thesis on Krater as a model for integrating spontaneous urban ecologies into urban planning through multi-species alliances and contributed to the Slovenian pavilion Master Builders at the 2025 Venice Biennale.

Altan Jurca Avci is an architect based in Ljubljana whose work operates through cooperative and collective forms of practice. His recent projects explore questions of land, stewardship, and collective organisation. Through such practice, he examines the socio-political conditions shaping architectural production.

Julia Udall is an architectural researcher, educator and practitioner based in Sheffield, UK. Her work explores urban commons, feminist community economies and ecosocial design through collaborative and transdisciplinary methods. Recent projects including Snorkelling in Soil and Sonic Acts of Noticing bring together artists, scientists and architects through deep listening and collective enquiry into ecological and social urgencies. She is a director of Studio Polpo.

Enja Grabrijan is an emerging ethnologist, musician, and illustrator whose work engages with environmental perception, reciprocity, care, and practices that foster positive relationships with the living world. Her anthropological research often intersects with illustration and musical interventions.

Gaja Mežnarić Osole from Krater Collective is an eco-social designer working at the intersection of urban nature, multispecies entanglements, and cultural production, highlighting interdependence and collective practices amid ecological and cultural precarity. Her work critiques assumptions around invasive plants, degraded sites, and sustainability measures—and examines how these shape cultural and ecological perceptions. She engages post-colonial and post-industrial approaches to nature through regenerative material cultures (Notweed Paper, Feral Flowershop), urgent pedagogy (Feral Palace, with Danica Sretenović), community infrastructure (Krater, Trajna, with Andrej Koruza), and policy initiatives (Mechanisms of Protection). Her practice is disseminated through exhibitions, publications, and teaching, fostering transdisciplinary engagement and transformative workplaces for emerging cultural practitioners. She co-curated this year’s programme of Soil Assembly in Ljubljana.

Andrej Koruza from Krater collective is an intermedia artist and designer working across DIY culture and sustainable infrastructures. Currently he is focusing on bio-based materials as a way to engage with community economies and more-than-human collaborations. Since 2017, he has co-led Trajna, co-produced Krater infrastructure, led on-site soil enriching activities and co-curated this year’s Soil Assembly in Ljubljana.

Access:
By bus: 6, 8, 11, 19 (“Astra” stop)
By car: parking garage Bežigrajski dvor (Peričeva ulica 15)
By bike: the nearest BicikeLJ city bike rental service station is located on “Astra” bus stop
On foot: walking distance from the city centre (20 minutes)

SoilTribes (101157729) is funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Executive Agency (REA). Neither the European Union nor the European Research Executive Agency (REA) can be held responsible for them.