Bokashi Composting in Small Apartments

What bokashi is

Bokashi is a fermentation method that processes kitchen scraps using a bran inoculated with effective microorganisms (EM). Unlike hot composting, which relies on thermophilic bacteria and requires outdoor space, bokashi works in an airtight bucket at room temperature. The process was developed in Japan in the 1980s and has since been adapted for residential use across Europe.

The name comes from the Japanese word for "fading away" or "gradual fermentation." The material in the bucket does not decompose during the fermentation phase — it pickles. Decomposition happens later, after the fermented pre-compost is buried in soil or added to a hot compost pile.

How the two-bucket system works

Most household bokashi setups use two identical buckets with lids and a tap at the base. While one bucket is being filled, the other sits sealed and fermenting. This alternating schedule keeps the process continuous without interruption for emptying.

Each time scraps are added, a tablespoon of bokashi bran is sprinkled over the material. The bran contains the microbial inoculant — typically Lactobacillus strains, yeasts, and phototrophic bacteria — preserved on wheat or rice bran. The lid is replaced immediately to maintain anaerobic conditions. Air exposure at this stage can introduce mould.

After two to four weeks with the bucket sealed, the contents are ready for the next stage. A white mycelium layer on the surface is a sign of healthy fermentation. Black or green mould indicates contamination, usually from excess moisture or air entry.

Bokashi tea

The liquid that drains from the bucket — drawn off via the tap every two to three days — is often called bokashi tea or bokashi juice. It is acidic, with a pH typically between 3 and 4. Diluted at roughly 1:100 with water, it can be applied to houseplants or garden soil as a microbial supplement. Undiluted, it is used to clear sink drains, where the acid and microorganisms suppress odour-causing bacteria.

The tea should not be poured neat onto plant roots. At full concentration it is too acidic for most soil organisms and can suppress plant growth rather than support it.

Processing the pre-compost in urban Poland

The most straightforward disposal route — burying in a garden plot — is not available to most apartment dwellers in Polish cities. Several alternatives exist.

Community gardens and allotments

Poland has a substantial network of rodzinne ogródki działkowe (ROD) — family allotment gardens administered under the Polish Allotment Gardens Federation. Many plots in Warsaw, Kraków, Wrocław, and other cities accept fermented kitchen waste from neighbours who do not hold their own plot, either informally or through organised schemes. The fermented material, buried 15–20 cm below the surface, breaks down in two to three weeks and improves soil structure.

Hot composting addition

If a hot compost pile is available — on a balcony in a tumbler, or in a shared yard — the bokashi pre-compost can be layered into it. The acidic, nitrogen-rich material accelerates the breakdown of carbon-heavy materials like cardboard and dry leaves.

Raised bed burial

Some Warsaw and Kraków residents with access to communal courtyard raised beds bury bokashi pre-compost between planting rows. Most Polish urban housing cooperatives (spółdzielnie mieszkaniowe) permit this, though it depends on the site's by-laws.

Odour management in an apartment

Correctly run bokashi bins produce a slightly sour, fermented smell — noticeable when the lid is opened, but not pervasive in a kitchen. The most common source of persistent odour is a lid that does not seal tightly, or scraps added wet without blotting. Placing the bin under the sink or in a cupboard reduces ambient odour further.

If the contents smell strongly of putrefaction rather than fermentation, the bin has been contaminated with air. The batch is typically lost, but the bucket can be cleaned with diluted white vinegar and restarted.

Equipment available in Poland

Bokashi bran and starter kits are available from several Polish suppliers as well as through pan-European online retailers. Sets typically include two buckets, a supply of bran for several months, and a measuring scoop. Replacement bran is the recurring cost. Polish composting retailers such as Bokaszeria and Sklep Ogrodnika stock both imported Japanese inoculants and domestically produced bran.

Some Polish municipalities — including several Warsaw districts — have offered bokashi starter kits as part of household waste reduction programmes. Availability varies by year and district budget cycles; checking the local gmina's environmental office website is the most reliable way to confirm current offers.

Source: Information on effective microorganisms sourced from publicly available technical documentation by EM Research Organisation (EMRO). Polish allotment garden information from the Polski Związek Działkowców (PZD).