Seed balls (Nendo Dango): how to sow biodiversity and transform cities
Urban Green Club SCASeed bombs, or Nendo Dango, are compact spheres made of clay, topsoil, and native seeds designed to revegetate urban spaces without the need for tilling the soil. It is an ancient, accessible technique with a real impact that any educational center, company, or city council can implement.
However, the context in which they are born is not insignificant: according to a study by ISGlobal published in The Lancet Planetary Health, 62% of the European population lives in areas with fewer green spaces than recommended by the WHO, a deficiency associated with nearly 43,000 avoidable premature deaths per year. In Spain, 58% of citizens consider creating green zones to be the most effective measure to improve urban biodiversity, according to the Sanitas Healthy Cities Monitor (2024).
In this context, techniques like Nendo Dango are not a creative curiosity. They are a practical, simple, and profoundly transformative response.
At Urban Green Club, an Andalusian B Corp specializing in urban gardens, we see it in every workshop: cultivating is a transformative act. And sometimes, that change starts with something as small as a ball of clay.
The philosophy behind Nendo Dango: sowing without tilling
Nendo Dango is a sowing technique that protects the seed inside a clay ball until environmental conditions are right for it to germinate, without the need to disturb the soil.
Its logic is based on non-intervention: letting nature lead the process.
The legacy of Masanobu Fukuoka and natural farming
This technique was popularized by Masanobu Fukuoka, a Japanese farmer, biologist, and philosopher considered one of the fathers of natural farming. His approach broke away from conventional agriculture:
- no tilling,
- no chemical use,
- no more intervention than necessary.
Seed bombs are born from this philosophy. The clay protects the seeds from predators and adverse conditions, and nature does the rest when the rain arrives.
This approach connects directly with what we now know as Nature-Based Solutions (NbS): strategies that use natural processes to solve urban environmental and social challenges, endorsed by the Ministry for the Ecological Transition of the Government of Spain. Instead of intervening aggressively, you accompany the process.
Step-by-step guide: how to make your own seed bombs
To make seed bombs, you need red clay, topsoil, worm castings, native seeds, and water. The process can be completed in less than an hour and requires no prior experience.
The ingredients and their functions
Each element plays a key role within the bomb:
- Clay → protects the seeds from birds, insects, and weather conditions.
- Topsoil + worm castings → provide nutrients and serve as a germination medium.
- Seeds → preferably native and adapted to the local environment.
- Legumes → improve the soil by fixing atmospheric nitrogen.
- Thyme or other natural repellents → reduce the risk of animals eating them.
- Water → gives cohesion to the mixture.
This balance is what turns a simple ball of earth into a potential living system.
The master ratio for success
According to the protocol used in Urban Green Club workshops in Andalusia, the proportions are key:
- 25 g red clay
- 15 g topsoil
- 10 g worm castings
To this, add:
- 1 tablespoon of flower or aromatic seeds
- 1 teaspoon of legumes
- a small amount of dried thyme
The mixing and modeling process
- Sift the substrates — Remove stones or clumps so the mixture is homogeneous.
- Mix dry ingredients — Clay, soil, humus, and seeds must be well integrated before adding water.
- Add water gradually — Until you achieve a texture similar to modeling clay.
- Form the balls — About 3 cm (golf ball size).
- Drying — Let dry for at least 48 hours before using.
- Sowing — Lightly bury or throw onto the terrain.
No machinery or prior experience is needed. Just an understanding of the process.
From the classroom to the earth: the Urban Green Club experience in Andalusia
The greatest value of seed bomb workshops in Andalusia lies in turning a simple technique into a collective experience with real impact.
On February 21, 2026, Urban Green Club held a workshop at the Ecohuerto Arabuleila (Armilla, Granada) where students and participants worked directly with natural materials.
During the session:
- seeds, clay, and soil were explored sensually
- the needs of a growing plant were understood
- seed bombs were made collaboratively
- there was reflection on biodiversity and nutrition
This type of workshop goes beyond the symbolic. They connect knowledge, practice, and community in the same space. This is where the garden becomes a living classroom.
Educational and environmental benefits of seed bombs
The educational benefits of seed bomb workshops include sensory development, fine motor skills, learning about the plant life cycle, and fostering respect for biodiversity.
Research published in the IberoCiencias Journal (2025) confirms that school gardens strengthen ecological awareness, promote responsible attitudes toward the environment, and encourage meaningful learning.
In our experience with workshops in schools across Granada and Andalusia, this translates into:
- Practical understanding of the plant life cycle
- Sensory development and fine motor skills
- Contextualized learning of scientific concepts
- Tangible introduction to urban biodiversity, soil regeneration, and sustainable food
And they do so through action, not theory.
Seed bombs as a tool for urban renaturalization
Seed bombs are one of the most accessible ways to apply Nature-Based Solutions in the city: they do not require large investments or complex infrastructure, but they do require real involvement.
At Urban Green Club, a B Corp based in Andalusia, we work with this and other methodologies within our environmental education programs in Granada and throughout Andalusia. We design experiences that:
- turn courtyards into living classrooms
- activate underused urban spaces
- generate community around cultivation
Because planting a seed doesn't change a city. But it can change the way a person relates to it. And that is where it all begins.
Planting a better future, even when hands get stained with clay
Nendo Dango is not a one-off technique or a single-day activity. It is a way of acting meaningfully in the city, with real impact and continuity.
At Urban Green Club, planting a better future is what we do every day.
Do you want to implement seed bomb workshops in your center or company in Andalusia?
We design environmental education workshops and tailor-made renaturalization programs for:
- Educational centers
- City councils
- Companies
With real guidance and adapted to the context of each project, in Granada and throughout all of Andalusia.
👉 Request information about Environmental Training and Workshops in Andalusia
Frequently asked questions about seed bombs
What are seed bombs?
Seed bombs are clay balls containing native seeds and nutrients, designed to protect them until they germinate under proper conditions. They are also known as Nendo Dango, a Japanese term meaning "clay ball."
How are seed bombs made step by step?
Clay, topsoil, worm castings, and seeds are mixed in specific proportions, water is added until a modeling clay texture is achieved, balls of about 3 cm are formed, and they are left to dry for 48 hours before use.
What seeds can be used in seed bombs?
Preferably native seeds, wildflowers, aromatics, and legumes adapted to the local climate.
Where can seed bombs be used?
In gardens, abandoned lots, degraded areas, schoolyards, or pots, always respecting the environment and local regulations.
How long do seed bombs take to germinate?
It depends on the species and weather conditions, but it can vary between a few days and several weeks.
Where to hire a seed bomb workshop in Andalusia?
Urban Green Club, a B Corp based in Andalusia, designs and conducts customized seed bomb workshops and environmental training for educational centers, companies, and city councils in Granada and throughout Andalusia. Request information here.
