Make your own bokashi bucket: two buckets, some holes, a tap and a good airtight seal

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A bokashi bucket is nothing complicated: an airtight container, a perforated base that lets the liquid drain away, and a space underneath to collect it. With two recycled buckets, a drill and an hour to spare, you can make your own for just a few euros.

The DIY part is simple; the airtight seal, however, needs care. It is what makes the difference between a bucket that ferments cleanly and one that smells bad. Here is the step-by-step method, the pitfalls to avoid and an honest comparison with a shop-bought bucket.

The principle: two nested buckets

The classic set-up uses two identical buckets, one slotted inside the other:

• the upper bucket, with holes in the base, takes the waste and the bran;
• the lower bucket, left intact, collects the liquid that drains through the holes;
• an airtight lid closes the whole thing.

As an option, a tap fitted at the bottom of the outer bucket lets you drain the liquid without taking anything apart. As with a shop-bought model, ideally you will need two sets: one fills up while the other ferments, as we explain in the guide Why use two bokashi buckets? In the diagram: the perforated upper bucket that takes the waste (1), the space where the liquid drains (2) and the drainage tap (3).

What you need

• Two identical buckets of 10 to 20 litres that nest together well, with at least one lid that closes airtight, ideally fitted with a seal. Choose food-grade buckets (marked with the glass and fork symbol): bakeries, pizzerias, caterers and restaurants often throw them away. Avoid buckets that have held paint, filler or chemicals.
• A drill with a 3 to 6 mm bit, plus a craft knife or a hole saw if you are fitting a tap.
• A plastic tap (optional), with its seal and nut: a tap from a barrel, a water container or a wine box does the job very well, as do those sold for home brewing.
• A waste press: a potato masher, a saucepan lid smaller than the bucket, or a plastic plate.
• Sandpaper to smooth the edges of the holes.

As for size, allow around 10 litres for one or two people and 15 litres for three or four: ideally the bucket should fill up in about two weeks.

Drilling the upper bucket

Turn over the bucket that will take the waste and drill twenty to thirty holes of 3 to 5 mm, spread evenly across the whole base. There is no need to be very precise: tutorials range from around thirty small 3 mm holes to around fifteen holes of 6 to 8 mm. The smaller the holes, the more you need, but the less waste falls through. Two precautions:

• do not drill too close to the edge or too close together: a base riddled with tightly packed holes can crack;
• smooth each hole with sandpaper so that no small bits of plastic are left hanging.

Holes of this size let the liquid through but hold back most of the waste. To stop them clogging, spread a centimetre of rinsed fine gravel or pozzolana, or half a sheet of scrunched-up newspaper, over the base before the first layer.

Leaving space for the liquid

This is the most common pitfall. Many buckets are slightly tapered: once nested, the base of the upper bucket sits almost at the bottom of the lower one, leaving only a few millimetres for the liquid. The liquid then rises back into the waste, which ends up sitting in it and smelling bad.

Before drilling anything, nest your two buckets and measure the free space underneath. You need several centimetres, and more if you are fitting a tap. If there is not enough, there are two solutions:

• cut a third bucket of the same model to make a spacer: cut off its base to keep a ring a few centimetres high, which you slide between the two buckets;
• rest the upper bucket on a small, stable support placed in the bottom of the lower bucket, for example an upturned plastic flowerpot.

Emy's tip

Nest your buckets while empty and pour water into the upper one before you start using them. You will see straight away whether the liquid drains properly, how much the lower compartment can hold, and whether the tap leaks.

Fitting a tap (optional)

Without a tap, you have to lift out the upper bucket to empty the liquid, which becomes heavy and messy when it is full. A tap makes draining much easier:

1. Choose its position as low as possible on the outer bucket, while leaving room for the nut on the inside and without stopping the bucket from standing flat. Mark it with a felt-tip pen.
2. Drill a hole the diameter of the tap's thread, using a hole saw or a craft knife, working gently: thin plastic cracks easily.
3. Fit the tap with its seal on the outside, then the nut on the inside, and tighten firmly without forcing.
4. Carry out a leak test: fill the bucket with water, with the tap closed, and leave it for an hour. Not a single drop should appear around the fitting.

Remember to close the tap after each draining: left open, it lets air in. If the tap ends up a little high, tilt the bucket slightly to finish emptying it. For how often and how to drain, see the guide Looking after your bokashi.

The airtight seal: the critical point

Bokashi is an oxygen-free fermentation. A bucket that lets air in produces coloured mould and bad smells, however good your bran is. Three areas need watching:

• The lid: it must close firmly, ideally with a seal. A poorly fitting lid can be remedied by placing a clean cloth or cling film over the bucket before clipping it shut.
• The join between the two buckets: if air can get between the two rims, it rises through the holes in the base. Wrap the join with adhesive tape, or slip a cut bicycle inner tube around the rim of the lower bucket to act as a seal.
• The tap, with its seal tightly fitted, and always kept closed.

Inside, also limit the air in contact with the waste: after each addition, sprinkle on the bran, press down, then place a plate or a smaller lid flat on the surface. You can add a clean weight on top, such as a jar filled with water.

Key points

A successful homemade bucket means a perforated base that drains well, a proper liquid compartment, and a careful seal at the lid, the join between the buckets and the tap. Test it with water before using it.

The three-bucket version

A clever variation, very popular in DIY workshops, uses three small 5-litre food-grade buckets with lids:

• the first, drilled with numerous 3 mm holes, takes the waste on a thin layer of gravel or pumice;
• the second, with its base cut off at around 7 cm, acts as a spacer and creates the liquid compartment;
• the third, left intact, collects the liquid and holds the tap.

This format is compact and well suited to a single person or a small flat. On the other hand, it fills up quickly: plan for two sets, or empty it more often.

Homemade or shop-bought: a comparison

The homemade bucket

• It costs next to nothing if you use recycled buckets.
• It lets you choose the capacity and reuse materials.
• On the other hand, you have to take care of the seal yourself, the liquid compartment is often small, and the whole set-up is bulkier and less discreet in a kitchen.

The shop-bought bucket

• It is designed for the job: a lid with a seal, a grid, a well-placed tap or plug, a suitable press, and a format designed for the kitchen.
• Our Comfort Bokashi composter, for example, has a double-sealed lid, a tap and a compactor; the Skaza Organko 2 relies on a pressing system and a compact, easy-to-carry format.
• It costs more, but saves you the trial and error.

To compare models in detail, see our guide How to choose your bokashi composter. And whatever your bucket, fermentation depends first and foremost on good bran: you can use our Bokashi EM compost activator or make your own with our guide Making your own homemade bokashi activator.

In summary

A homemade bokashi bucket is made with two identical food-grade buckets: the upper one, drilled with twenty to thirty holes of 3 to 5 mm, takes the waste; the lower one collects the liquid, possibly via a tap fitted as low as possible. Check that there are several centimetres left for the liquid, adding a spacer if necessary, and take care with the seal at the lid, the join and the tap, before testing with water. It is economical and effective; a shop-bought bucket mainly offers convenience, discretion and a seal already designed for the job.

Related products

Skaza Essential Bokashi Composter

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£53.53 €64.17

Kit to make your own Bokashi & Compost Activator | 4 kg Kit

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20 ml measuring spoon

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Best Seller

Bokashi Confort Composter

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Other topics in the guide

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