Bokashi Composting

Bokashi composting is an anaerobic fermentation process that converts kitchen waste into a nutrient-rich soil conditioner. 'Bokashi' is Japanese and means 'fermented organic matter' or literally ‘softening’. The Bokashi process involves fermenting waste organic matter in an anaerobic environment using a bran inoculated with beneficial microorganisms, known as Bokashi bran. These microbes produce bio-active substances like enzymes, vitamins, antimicrobials, and phytonutrients, which favour plant development and help prevent diseases. Unlike traditional composting, Bokashi composting occurs in an airtight container, producing a pre-compost that can be further decomposed in the soil.

Benefits of Bokashi Composting

  1. Speed: Bokashi composting is faster than traditional methods, typically taking 2-4 weeks to ferment waste.
  2. Odour Control: The anaerobic process significantly reduces odours compared to aerobic composting.
  3. Versatility: It can handle a wider range of organic materials, including meat and dairy, which are usually excluded from other composting methods.
  4. Nutrient Retention: The fermentation process retains more nutrients, enhancing the quality of the compost produced.
  5. Space Efficiency: Bokashi systems are compact, making them suitable for urban environments and small spaces.

What's Suitable/Unsuitable to Compost

Suitable:

  • Fruit and vegetable scraps
  • Meat, fish, and dairy products
  • Cooked and raw food leftovers
  • Bread and other grains
  • Coffee grounds and tea bags
  • Eggshells
  • Small amounts of paper and cardboard

Unsuitable:

  • Large bones
  • Excessive amounts of liquids (soups, oils)
  • Mouldy or rotten food
  • Plastics, metals, and other non-organic materials

How to Make Bokashi

  1. Sprinkle a bit of Bran first into the bottom of the bucket.
  2. Add chopped food waste (maximum 5 cm pieces) in layers.
  3. Sprinkle 1-2 tablespoons of Bokashi Bran per kilo of kitchen waste.
  4. Press food waste firmly with the presser and close the lid tightly.
  5. Continue layering until the bin is full.
  6. Finish with a final layer of Bokashi Bran. Seal with the air-tight lid.
  7. Drain the Bokashi liquid regularly.
  8. Allow the waste to ferment for 2 weeks before use.

Troubleshooting

  • Bad Smell: A strong, unpleasant odour indicates that air may have entered the bin. Ensure the lid is airtight and use enough Bokashi bran.
  • Pests: If you encounter pests, it could be due to improper sealing or exposure to air. Check the seal and ensure the bin remains closed.
  • Too Much Liquid: Excess liquid can hinder fermentation. Drain the liquid regularly and avoid adding overly wet materials.
  • Mould: White mould on the surface is normal and indicates successful fermentation. Green or black mould signifies spoilage; discard the contents and start over.

What to do with Bokashi Liquid

Bokashi leachate, also sometimes called Bokashi tea or Bokashi juice, is the liquid that accumulates in a Bokashi composting bin. It's a byproduct of the anaerobic fermentation process that breaks down food scraps.

This liquid is highly beneficial but should be handled with care:

  1. Drain Regularly: Collect the liquid every few days using the tap at the bottom of the Bokashi bin.
  2. Dilute for Use: Dilute the liquid at a ratio of 1:100 (one part liquid to one hundred parts water) before using it as a fertiliser for plants. Undiluted liquid can harm plants due to its acidity.
  3. Use as Drain Cleaner: Undiluted Bokashi liquid can be poured down drains to help break down organic matter and reduce odours.

What to Do with Bokashi Compost

Direct Soil Integration

To integrate Bokashi pre-compost directly into your garden, dig a trench about 20-30 cm deep and spread the Bokashi compost evenly. Cover the trench with soil and let it decompose over 4-6 weeks. This method enriches the soil with nutrients and beneficial microbes, creating a thriving soil ecosystem and enhancing plant growth.

Compost Acceleration

Incorporate Bokashi pre-compost into your standard compost pile by layering it with green and brown waste. The facultative nature of Bokashi microbes increases the pile's temperature and microbial activity, accelerating decomposition. This process not only speeds up composting but also reduces odours and enriches the compost with a diverse microbial population.

Wormery Enrichment

Add Bokashi pre-compost to your wormery by mixing it with bedding material. Worms benefit from the predigested nature of Bokashi compost, making it easier for them to consume and produce nutrient-rich vermicompost. However, because Bokashi compost can be acidic, introduce it gradually to allow the worms to acclimatise. This synergy enhances the vermicomposting process, resulting in a high-quality, nutrient-dense compost ideal for plant growth.

Soil Factory Rejuvenation

A ‘soil factory’ is a method for rejuvenating old potting soil using Bokashi pre-compost. To set up a soil factory, mix one-third Bokashi pre-compost with two-thirds old potting soil in a large container or bin. Allow the mixture to mature for a few weeks, turning it occasionally to aerate. This process restores the fertility and structure of the old potting soil, making it suitable to use for plants again.