From green waste to fertile soil: our new Bokashi station!
06/05/26
At Stadsjochies, we are constantly working on the question: how can we be even more circular? A big step in this direction is our new Bokashi Station, a place where we convert our own green waste into food for the soil.
Our cultivation manager Koen enthusiastically talks about the process, the benefits and why this fits perfectly with how we want to work: local, sustainable and fully connected to nature.
What is Bokashi anyway?
Bokashi is a natural way of fermenting. Instead of composting, where oxygen is actually important, Bokashi works without oxygen. This is called an anaerobic process. By adding fermentation bacteria, organic material is slowly broken down into a nutritious soil improver.
“It's basically completing the cycle,” Koen explains. “All the green waste that comes out of the garden during the year, you end up giving back to the soil.”
An on-site circular system
Large concrete walls are currently being installed on the site. Here we are building several compartments where we will separate and collect waste streams.
We also store compost from Agterberg here. We buy this compost locally, literally five minutes away. That makes it not only affordable, but also sustainable: the compost is made from green waste from Utrecht and its surroundings.
Three types of green waste
The Bokashi Station will soon consist of three separate compartments:
1. Prunings: Branches, bushes and other pruning material are first made smaller with a shredder. “The structure of the Bokashi is important. The smaller you make the material, the better the fermentation process works,” Koen explains. “If you throw a whole branch in the heap, it will also come out largely as a branch in the end.”
2. Garden waste: In the second compartment, we collect leaf cuttings, grass clippings, trimmings and other green waste that does not require shredding and which comes from our own garden.
3. Cressen waste from our vertical farm: The residual material from our vertical farm also gets a second life. This is because the used soil in which the cresses grow still contains a lot of nutrients. “We don't throw those nutrients away,” Koen explains. “We reuse them in the Bokashi heap.”
A living layer cake
From the three compartments, we will soon build up the Bokashi pile layer by layer:
- pruning waste first,
- then garden waste,
- then cressen waste
Building up these layers creates a fermentation process. There will also be a Bokashi street with solid walls, so that the heaps can be built up higher and pressed down better. This pressing is important, because with Bokashi you want as little air in the heap as possible.
Why Bokashi is so special
Whereas composting produces heat through bacterial activity, Bokashi remains relatively cool. This also means that the process is slower in winter. On average, fermentation takes about 12 to 16 weeks, depending on the season. But the result is worth it: a nutritious, living soil improver that is eventually broken down again naturally by the soil life in our garden.
Coming full circle
For us, the Bokashi Station is more than just waste processing. It shows exactly what Stadsjochies stands for: working locally, dealing smartly with residual flows and letting nature do its work as much as possible.
What once started as trimmings, grass clippings or cress leftovers ends up feeding new vegetables, herbs and flowers. And that, perhaps, is what we like best of all.