Bokashi and garden compost: how to add your fermented bokashi to the compost bin

Print

Do you have a compost bin at the bottom of the garden and a bokashi bucket in the kitchen? That's an excellent combination. The bucket takes almost all your meal leftovers, meat and fish included, and the compost bin completes their transformation. The fermented contents finish breaking down there in about a month, among the other materials.

Provided you add it properly: a bucket tipped out in one lump onto the heap stays acidic and wet, and can slow down the whole compost. Here's how to make bokashi a valuable addition to your compost bin.

Bokashi: a "green" addition

In a compost bin, you balance moist, nitrogen-rich materials, the "greens", with dry, carbon-rich materials, the "browns". Fermented bokashi is undoubtedly a green: it is moist and rich in nitrogen and easily decomposed matter. So, like peelings, it needs a good dose of brown materials: dead leaves, shredded material, brown cardboard, straw. If this principle is new to you, our guide Green and brown materials explains everything.

What sets it apart is its acidity. Compost gets off to a poor start in an overly acidic environment, yet it easily digests an acidic addition buried in material that is already active. Hence the three rules that follow: spread, mix, cover.

Did you know?

The acidity of food waste is a well-known problem at composting facilities: in trials, a mix that stayed below pH 6 did not heat up and almost stopped decomposing. The solution turned out to be very simple: add enough already active compost, whose micro-organisms consume the acids and raise the pH.

Spread and mix, don't tip it out in one lump

1. Dig a hollow in the centre of the heap or bin, where the material is most active.
2. Empty the bucket, spreading out the contents rather than leaving them in a single compact lump.
3. Mix it in with a fork, together with decomposing compost and one or two spadefuls of soil.
4. Add brown materials, at least the same volume as the bokashi.
5. Cover everything with a good layer of brown materials or compost, about twenty centimetres deep.

Unlike the bucket, which you never stir, the compost bin needs air: once the bokashi has been added, manage the heap as usual, turning it regularly.

Emy's tip

Keep a bag of dead leaves or shredded material next to the compost bin, set aside for the days you empty the bucket. A good armful per bucket, and you'll never be caught short.

Cover: against smells and animals

Well covered, bokashi keeps a low profile. Left on the surface, it gives off a sour smell that can attract flies, neighbourhood cats, foxes and sometimes rodents, especially if it contains meat or fish. A closed compost bin with a lid is therefore preferable to an open heap. If you've already had unwelcome visitors, lay fine wire mesh under the bin and always bury the bokashi deep in the material. Bokashi is in no way a repellent: what keeps visits down is the way it is covered. Our guide Pests in the compost bin details good practice.

Correcting the acidity

In a compost bin that is working well and already rich in decomposing material, the acidity of a bucket of bokashi is absorbed without difficulty. If your compost bin is small or just getting started, you can give it a helping hand:

• a handful of crushed eggshells or crushed shellfish shells;
• a small amount of gentle liming material, such as dolomite or agricultural lime.

Avoid quicklime or slaked lime, which are too caustic: they slow down the micro-organisms you need. And don't add it every time: a well-balanced compost regulates itself.

How long until the compost is ready?

In an active compost bin, bokashi is one of the fastest materials to disappear: allow about a month until it is no longer recognisable. The compost, however, follows its own pace. It generally takes several months to obtain mature compost, depending on the season, the size of the heap and the care taken with additions and turning. The stages of this transformation are described in our guide The phases of composting.

Bokashi doesn't shorten these timescales dramatically, and we prefer not to promise you compost that is "twice as fast". Its real benefit lies elsewhere: it brings into the compost bin leftovers you would otherwise have thrown away, meat, fish, dairy products or cooked dishes, already stabilised by fermentation. As for effective micro-organisms sprayed directly onto the heap, we take stock in the EM guide article Speeding up your compost with EM.

In winter

The compost bin is a good solution when the ground is frozen or too waterlogged to dig. Bokashi breaks down more slowly there in cold weather, but it is sheltered under the brown materials, and the transformation resumes in spring. A closed compost bin, such as the Compostys wooden composter, also protects it from rain and animals.

Large volumes, rotating composters and community compost

Several buckets at once

If you empty several buckets at the same time, after a holiday or at the end of winter, spread them throughout the heap rather than concentrating them in one place, and double the amount of brown materials. For very large volumes, burying in a trench in the vegetable garden is often simpler: see our guide Burying your bokashi in the garden.

The rotating composter

In a rotating composter, pour the bokashi into the compartment currently being filled, along with a good handful of dry material. Turning the drum mixes it effectively, and the already fermented leftovers break down well.

The shared compost bin

Before emptying your bucket into a neighbourhood or apartment block compost bin, ask the person in charge for permission. Many charters refuse meat and fish, even fermented, to avoid pests. If yours accepts bokashi, follow the same rules as at home: in the centre, mixed in, well covered.

Key points

In the compost bin, bokashi is a green material: spread it in the centre of the heap, mix it with active compost, add at least the same amount of brown materials and cover it well.

In summary

A garden compost bin is an excellent outlet for fermented bokashi. Treat it as a green material, acidic and moist: spread it in the centre of the heap, mix it with fully active compost, add at least the same amount of brown materials and cover it carefully. It disappears in about a month, without dramatically shortening the compost's maturation, but it lets you add all your meal leftovers. If in doubt about acidity, a few crushed shells are enough.

Related products

Compostys wooden composter | 305 litres

PEFC-certified spruce wood

€142.47

Bokashi Composter Skaza Organko 2

Capacity 9.6 litres, sold individually or in a set of 2

€83.01

Maze 180L Dual Chamber Rotating Composter

Effortless outdoor composting

€183.48

Best Seller

Bokashi EM compost activator | 1 kg bag

Individually or in sets of 2 or 3 bags

€8.15

Other topics in the guide

Vermicomposting30 sheets →Composting25 sheets →EM micro-organisms26 sheets →