Make your own Bokashi bucket – composting the Japanese way

Bokashi – useful background information

Before you start making your own Bokashi bucket, we’ll answer the most frequently asked questions about the Japanese alternative to compost here. So, before the actual building instructions, here’s a little Bokashi guide.

What actually is a Bokashi bucket?

The word ‘Bokashi’ is Japanese and means something like ‘fermented material’. In a Bokashi bucket you can produce high-quality fertiliser with the help of kitchen waste and ‘effective micro-organisms’ (EM) without much effort, even if you are short of space at home. The micro-organisms decompose your kitchen waste. You can use both the resulting liquid and the Bokashiferment as fertiliser.

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What do I need to make Bokashi?

All you really need to make Bokashi ferment yourself is an airtight bucket from which you can let out moisture, and the commercially available effective micro-organisms. The size of the bucket depends solely on the space you have available.

Ready-made Bokashi buckets are available in stores for €30 to €80. If you want to build your own version, you will need two buckets (see instructions), and the whole thing will cost you just €15.

What can and can’t you put in a Bokashi bucket?

You can feed your Bokashi bucket with garden and kitchen waste that has been cut up as small as possible, including plant waste, fruit and vegetables, including peel, stones and seeds, cooked food, eggshells, bread, meat and fish or even coffee grounds. A mixture of different materials in each layer is ideal.

How exactly does a Bokashi bucket work?

The Bokashi bucket as a composter or alternative: You stack your material, i.e. the kitchen waste, in the Bokashi bucket to form different layers and compact each layer down, e.g. with a masher or a ladle. You spray each 3 to 4 cm high layer with the effective micro-organisms until it shines with moisture. You can weigh down each new layer with a bag full of sand, water or pebbles. The layer must be completely covered.

No air should get to the ferment, so it’s important to close the lid tightly again after each opening. If the bucket is already almost full with layers, making it airtight by closing the lid is sufficient  – there is no need to additionally weigh the layers down.

Now, all you have to do is wait. You should check every 2 to 3 days whether you can draw liquid from the tap. We’ll explain what to do with it in a moment. When hardly any Bokashi juice is coming out, the ferment is also almost ready.

What is the difference between fermentation and composting?

In a conventional compost heap, the organic material rots in the air. Kitchen and garden waste decomposes over time into an soil-like substance. The finished compost contains only a few nutrients and is therefore less suitable as a fertiliser for demanding plants such as roses. In a separate article you can find out more about composting. If you have a free corner in your garden, you can build your own compost bin.

Bokashi and compost are not the same, because in Bokashi the airtight material is enriched by fermentation. It retains all the nutrients of the original organic material and, thanks to the effective micro-organisms, also takes on nutrients in the form of vitamins, minerals and enzymes. In addition, fermentation progresses much faster than decomposition in composting.

What does Bokashi smell like?

Unpleasant odours are often cited as a problem when it comes to composting or fermentation. If you want to keep your Bokashi bucket in the kitchen, this aspect is, of course, particularly important. But rest assured: While composting actually produces unpleasant odours due to the rotting process, the Bokashi ferment does not have a bad smell – it smells a little ‘sour’, but it’s not off-putting.

How long does the fermentation process take?

A full, tightly sealed Bokashi bucket should ferment for around 14 days. You can then open the bucket and check the ferment – does it smell slightly of apple cider vinegar and look a bit glassy? Then it’s ready. If not, close the bucket and check again after a week.

How do I use the Bokashi ferment as fertiliser?

You can take the ready Bokashi ferment directly from the bucket and mix it with soil. The content of a 16-litre Bokashi bucket is enough for about 100 litres of soil. You can also fertilise high nutrient-demanding plants such as tomatoes or potatoes with 1 kg of Bokashi per m2 or 250 g per plant.

If you want to fertilise existing plants, simply make 10 cm deep furrows in the soil between them and bury the Bokashi ferment in them. You can also draw a 10 cm deep circle around trees or shrubs, which should be about 30 to 40 cm from the root diameter. Finally, it is essential to cover the ferment again with soil.

What else can I do with the Bokashi ferment?

• Because Bokashi contains so many nutrients, you can also spread the ferment on cleared beds as fertiliser, where it quickly becomes valuable humus. Then wait two weeks before sowing new seeds or planting plants; they could be damaged by the fresh ferment.
• Mixed with other organic materials in an ordinary compost heap, Bokashi also acts as a compost accelerator.
• You can also enrich old soil with Bokashi to make nutrient-rich potting soil.

How can I use the Bokashi juice?

• The liquid you take from the Bokashi bucket is a first-class liquid fertiliser for plants. You can dilute 1 part Bokashi juice with 100 parts water and use it once a week for about three to four weeks.
• Bokashi juice has also proven to be an effective liquid cleaner, preventing dirt and odours from building up in drainage pipes and toilets. Dilute 1 part Bokashi juice with 100 parts water and apply it once every one to two weeks.