Making your own Bokashi: How kitchen waste improves the soil

We throw away apple peels, empty coffee grounds into the general waste, and chop up vegetable scraps and put them in the bin. Yet these supposed waste products contain exactly what many depleted soils desperately need: organic matter, microorganisms, and the foundation for a living water reservoir.

Especially during times of heat and drought, the importance of healthy soil becomes clear. Sandy, compacted, or depleted soils often retain water poorly. Rain seeps away too quickly or runs off the surface before the roots can reach it. Despite proper care, plants then become stressed.

A simple do-it-yourself method for better soils is called Bokashi.

What is Bokashi and how does it help the soil?

Bokashi is a fermented substrate that... soil life It activates and returns organic matter to natural cycles. The term originates from Japanese and roughly translates to "fermented organic matter".

The principle: Kitchen waste is not composted in the traditional way, but fermented under exclusion of air with the help of lactic acid bacteria and other microorganisms, similar to sauerkraut or kimchi.

What results is not finished humus, but a ferment that is further transformed in the soil. This process activates microorganisms, attracts earthworms, and allows soil life to begin breaking down the material. Humus to rebuild.

And here lies the connection to drought and soil quality: Humus is one of the most important natural water reservoirs in the soil. Humus-rich soils can absorb significantly more water and retain it longer than depleted soils. At the same time, the soil structure improves, allowing rainwater to infiltrate better instead of running off the surface.

You can learn in detail how closely soil quality, moisture and plant health are related in our Guide to the interplay of water, soil and nutrients.

Bokashi vs. classic compost: The difference

compost Bokashi and other composting methods pursue a similar goal: both help return organic material to the soil. However, the processes differ significantly. Classic compost is produced through aerobic decomposition with oxygen. This process often takes several months. 

Bokashi, on the other hand, ferments in the absence of air and is usually ready after two to three weeks. The fermentation process preserves many nutrients and keeps the material highly biologically active. Both methods can complement each other very well.

Step-by-step instructions: How to make Bokashi yourself

You don't need a garden or a compost heap. All you need is:

• an airtight Bokashi bucket
• Bokashi ferment or effective microorganisms
• organic kitchen waste

These materials are suitable for Bokashi:

• fruit and vegetable scraps
• Coffee grounds
• Teabag
• eggshells
• Bread
• cooked leftovers

Less suitable for Bokashi are:

• large quantities of liquid
• heavily moldy food
• larger bones

And here are the instructions:

1. Shred kitchen waste: The smaller the pieces, the faster and more even the fermentation process.
2. Layer and press down materials: Layer the kitchen scraps in the bucket, pressing them down firmly each time. Avoid oxygen as much as possible. Then sprinkle each layer with Bokashi ferment.
3. Seal airtight: Close the bucket tightly and store it in a protected place.
4. Let it ferment: The Bokashi is ready after about two to three weeks. It typically has a slightly sour smell, similar to sauerkraut or vinegar.

Note: White coating is usually harmless. However, a foul odor or dark mold indicates that too much oxygen has penetrated the system.

Using Bokashi correctly in the garden

The finished Bokashi ferment should not be applied directly to sensitive roots, as it is initially quite acidic. It is best to lightly work it into the soil and then cover it with earth. There, microorganisms and soil organisms will begin to convert the material into humus.

Bokashi is suitable for, among other things:

• vegetable beds
• Raised beds
• garden plants
• fruit trees
• Berry bushes
• Tree discs
• Houseplants in small quantities

Bokashi is particularly interesting for dry, sandy or biologically depleted soils.

Use Bokashi for trees

Trees benefit particularly from healthy and vibrant soil. Especially in cities, on new building sites, or in dry regions, soils are often compacted, low in humus, and have limited water retention capacity. As a result, trees quickly become stressed during prolonged periods of drought.

Bokashi can help improve soil quality around the root zone in the long term. When the fermented organic material is worked into the soil, it promotes the activity of microorganisms and soil organisms. These gradually break down the material into humus, creating a loose, fertile soil structure.

A humus-rich soil can absorb and retain significantly more water than a depleted soil. At the same time, the aeration of the root zone improves, and nutrients become more readily available. Young trees especially benefit from this, as they have not yet developed a deep root system and depend on a good water supply in the upper soil layer.

Bokashi can also contribute to soil improvement in urban areas. By promoting soil life and building up organic matter, it strengthens the natural resilience of the site. This often helps trees to better withstand periods of drought and grow healthier in the long term.

Important: Bokashi should not be applied directly to the trunk or delicate fine roots. The best way is to lightly work the ferment into the soil at a distance from the trunk and then cover it with soil. There it can decompose undisturbed and exert its beneficial effects on the soil.

For optimal water supply, it is recommended to combine soil improvement with Bokashi with targeted irrigation. Watering rings, tree discs, and a layer of mulch also help to retain moisture in the soil longer and protect the root area from drying out.

Tool tip: Bokashi bucket and Bokashi juice

For the production of Bokashi, an airtight Bokashi bucket is usually used. Many models also have a drain tap. During fermentation, in addition to the solid ferment, so-called Bokashi juice is also produced.

This can be used, highly diluted, as a liquid fertilizer for garden plants, balcony plants or houseplants.

Combining Bokashi, worm compost and Terra Preta

Bokashi is just one of several methods for improving soils in the long term. While Bokashi primarily ferments organic material and activates soil life, it also provides Worm compost already finished living humus with many microorganisms and plant-available nutrients.

biochar This in turn improves the soil's ability to store water and nutrients, especially in the long term.

The methods complement each other very well:

• Bokashi activated
• Worm compost revitalizes
• Terra Preta stores

In this way, a living and resilient soil is created step by step.

Advantages and disadvantages of Bokashi

Like any soil improvement method, Bokashi has both advantages and some disadvantages. However, those who use the fermentation of kitchen waste correctly can achieve many positive effects for soil, plants, and the environment.

Advantages of Bokashi

• Fast production: Unlike traditional compost, Bokashi is produced within just two to three weeks. While a compost heap often takes several months, the fermented material is available much faster.
• Minimal odor: Successful fermentation produces a slightly acidic smell, often compared to sauerkraut or vinegar. This makes Bokashi suitable for households without a garden or for use on balconies and patios.
• Nutrients are largely preserved: Because the organic materials ferment rather than rot, fewer nutrients are lost. This makes Bokashi a valuable addition to vegetable beds, garden plants, trees, and other crops.
• Possible even without a garden: All you need to make Bokashi is a bucket and a suitable spot in your apartment, basement, or on your balcony. This allows even people without a garden to make good use of their kitchen waste.
• Promotes soil life: Bokashi introduces organic matter and active microorganisms into the soil. This promotes earthworms and other soil organisms that are important for humus formation and good soil structure.

Disadvantages of Bokashi

• Purchase of a Bokashi bucket: The production process typically requires an airtight Bokashi bucket. Bokashi ferment or effective microorganisms are also needed and must be purchased regularly.
• The material must be incorporated into the soil after fermentation: The finished Bokashi ferment is not immediately usable humus. It must first be worked into the soil, where it is further broken down by microorganisms. Therefore, those without a garden or plant containers have limited options for using it.
• The ferment is initially sour: Freshly fermented bokashi has a low pH value and should therefore not come into direct contact with sensitive roots. A short maturation period in the soil is recommended before planting.
• Slightly more effort than the organic waste bin: For fermentation to be successful, kitchen waste must be regularly shredded, compacted, and stored airtight. While the effort is manageable, it is greater than simply disposing of it in the organic waste bin.