Want to get rid of cooked food at home or in the garden? Don’t have enough waste for a hot composter, and don’t like the idea of having a worm bin?
If that’s you, you might well be considering getting a Bokashi bin.
But hold your horses!
First off, you might want to know how to use a Bokashi bin and how it works.
If you’re a gardener, you’ll also want to know how it affects your soil.
We’ve put this comprehensive, research-based introduction to Bokashi bins together so you can choose if it is right for you.
- What is a Bokashi Bin?
- The history of Bokashi
- Who are they for?
- How do you use a Bokashi bin?
- What food waste can you put in?
- How do you use Bokashi ‘compost’?
- Does it work?
- What does the research say?
- Pros & Cons
- Which Bokashi bin should you choose?
- Alternatives to Bokashi bins
- Can you make your own?
What is a Bokashi bin?
A Bokashi Bin is an airless fermentation system that essentially pickles your waste.
Bins typically contain a grill on which waste sits. They also have a spigot to drain liquid.
The system uses microscopic organisms called ‘Effective Microorganisms’ (EM). This is a mixture of bacteria and yeast which ferments kitchen waste while avoiding the odour of rotting food.
These organisms are held in a carrying material called Bokashi bran. When the bran is added to food scraps, they start breeding and ‘digesting’ the food scraps.
The Bokashi system is often referred to as composting.
That’s not strictly correct. What you’re actually doing is fermenting the food before composting it or digging it into your garden. The finished result is sometimes called ‘pre-compost’.
The history of bokashi
The system was created by a Japanese agricultural scientist Dr. Teruo Higa.
The story goes that Higa had thrown out some waste after conducting experiments with microorganisms. He then noticed that the surrounding plants began to flourish.
Higa went on to develop and commercialise Bokashi. The system was first used in Japan in 1982, but is now sold around the world.
The term Bokashi may be new, but the principle is not. According to Park and Dupont, the deliberate collection and cultivation of micro-organisms has been used in Asian countries like Korea for centuries.
The Korean Natural Farming method also makes use of microorganisms to improve soil and reduce pathogens and odours.
Who is the Bokashi bin for?
The Bokashi bin is great for people who want to get rid of cooked waste at home but don’t have sufficient material for hot composting and don’t like the idea of a worm bin.
It’s not suitable for people who need large amounts of compost or who want finished compost from a single system.
How do you use the Bokashi bin?
Typically you have two Bokashi bins. These are air-tight, as Bokashi bins use an anaerobic fermenting process.
- Break up any large pieces of food waste to increase the surface area the bacteria can work on.
- Add a thin layer of bran to the bottom of the bin..
- Add 3-4 centimetres of waste food.
- Add a sprinkling of bran.
- Push down to reduce the amount of air and water content in the waste. A potato masher is good for this.
- Close the lid, ensuring it is airtight.
- Drain the liquid every other day. You can dilute this and use it as a fertiliser.
- Continue this process until the bin is full.
- Leave for 10-14 days, then either dig into your soil, your compost bin or add to your worm bin.
When the first bin is full and has been left to ‘brew’, you can then start filling the second bin.
What can and can’t you put in a Bokashi bin?
You can put most food waste in, including:
- vegetable and fruit peelings
- cooked and uncooked meat
- tea bags (ideally ones with no plastic in them)
You shouldn’t put in:
- larger meat bones
- food that is mouldy/rotten
- liquids such as milk or juice
There are also specific Bokashi systems designed to deal with pet waste.
How do you use Bokashi ‘compost’?
When the process is finished you are left with what is called ‘pre-compost’.
There are a number of ways to use this:
- Dig the pre-compost into the soil.
- Add it to a worm bin.
- Dig it into your compost.
Bokashi pre-compost is very acidic. If you dig it into your soil, avoid planting anything there for several weeks.
You can also use the ‘Bokashi tea’ produced during the Bokashi composting process as a liquid fertilizer.
However, this is acidic and needs diluting first. Some research suggests that Bokashi tea is not effective when it comes to increasing crop yields (see below).
Does the Bokashi bin system work?
The Bokashi Bin effectively ferments most kitchen waste, as long as you follow the instructions.
You do have to seal off the air, and you have to add sufficient Bokashi bran.
Some users have reported a smell. When I attempted to put food waste in the ‘compostable’ plastic bags our council provides us with, I ended up with a sticky mess. After following the instructions more carefully, though, I ended up with some fermented waste which I dug into my compost heap.
In general, as long as you follow the instructions to the letter your Bokashi will ferment food waste without any foul smells. (There will be a pickled, fermenting smell when you open the bin. Most people find this inoffensive.)
It will also produce compost tea which can be used as a fertiliser. It won’t, however, produce finished compost. The pre-compost need to be either dug into your compost heap or your soil.
If you have a large garden, the quantity you make won’t be significant. I’ve found it too much fiddle for the results myself, and I’ve gone back to adding my kitchen scraps to my hotbin composter.
What does the research say?
Research has looked at:
- if Bokashi increases crop yields
- if the microorganisms can reduce diseases in the soil
- if Bokashi tea can impact crop yields.
The research shows positive benefits on yields and inconsistent results on the ability to reduce pathogens.
For example, a study by Lasmini et al found a significant increase in the yield of shallots after adding Bokashi pre-compost. However, research by Shin et al found inconsistent results in the ability of Effective Microorganisms to suppress diseases in the soil.
There has also been limited research into the use of Bokashi compost tea, with a study by Knewtson et al finding no impact on crop yields.
There is controversy surrounding at least some of the research into Bokashi. For example, Planet Natural writes:
Most of the studies cited by these companies, especially by the U.S. company with close ties to Higa, appear to have been presented exclusively at the conferences his group sponsored and to have been published exclusively on his websites.
Pros & cons of Bokashi bins
It’s fun: I don’t know about you, but I certainly enjoy the process of fermenting. (I do, however, prefer it when the result is alcoholic rather than pre-compost.)
It takes a wide variety of waste: You don’t want to be putting cooked waste on an open compost pile, unless it is hot and you can dig it in. So having a closed system which doesn’t produce a rotting smell is a definite advantage.
Can be used inside or outside: Most composting systems are designed to be used outside. Having something which can be used inside is definitely a bonus.
Produces a liquid fertiliser: Do note, however, that there are some questions about whether this actually has any effect. (See the section on research above.)
Ongoing costs: You either have to buy Bokashi Bran or make it yourself. That contrasts to most compost systems which have no ongoing costs.
Doesn’t produce finished compost: Unfortunately, when the process is finished extra work is required in order to turn it into compost.
Benefits for soil may have been exaggerated: Again, that’s particularly the case for the liquid. Many Bokashi fans advise diluting it 100:1 with water to deal with the acidity. At this level of dilution, it may have little or no effect.
Which Bokashi bin should you choose?
Biolan Bokashi Starter Kit
The Biolan Bokashi starter kit is an attractive bucket with an insulated body and lid, and is suitable for both outdoor and indoor use. This device is both built to last and ensure that rodents are kept out.
It also has impressive eco credentials. It’s manufactured using solar and wind energy in Finland, and has managed to avoid the problems with clogging taps that people have reported with other brands.
Skaza Bokashi Organico Kitchen composter
Slovenian company Skaza also mind their ECO credentials, manufacturing their products from recycled plastic whenever possible.
A popular option in the UK, the Skaza Bokashi Organico Kitchen Composter package brings you two sturdy bin. It includes everything you need to get started including bokashi bran and a drainage cup.
Green Johanna: An impressive system which can compost cooked food waste. More expensive (at least initially), requires larger amounts of compost material.
Worm Bins: Wormeries can deal with a lot of kitchen waste, but not quite the same range as the Bokashi Bin. Unlike the Bokashi bin, worm bins create fine, finished compost.
Green cone: The Green Cone is a great solution for people who don’t need finished compost. It can get rid of cooked food waste, but requires digging into the ground.
Can you make your own Bokashi bin?
Yes, it’s easy and you can use any airtight containers – even large ice-cream containers.
You’ll need two containers to make a bin. The first one needs an air tight lid.
- Drill holes in the first container.
- Place it in the second container.
- Add your food scraps and Bokashi bran and place the lid on it.
- Place the first container in the second container.
- When you want to drain the liquid off, simply remove the first container and pour off the liquid. If you want to get fancy, you could also use a spigot to drain the liquid away.
Bokashi Bins can also be scaled up – some Bokashi bin fans even use dustbins to make large quantities.
Why isn’t it working?
Reasons why your Bokashi bin might not be working include:
- rotten or mouldy food
- larger meat bones
- not enough bran
- too much liquid
- oxygen getting into the mix.
Can you add worms to the Bokashi bin?
The system is designed to be airless, so it’s probably not advisable to add worms when used as designed.
However, I have used my own bokashi bins for collecting waste in the greenhouse, and have found worms happily munching on the results when the lid has been left ajar. Worms are also quite happy to eat fermented bokashi waste.
Why am I not getting liquid?
You’re probably adding dry food – moist food will produce more liquid for use as a fertiliser.
Can you make Bokashi bran?
Yes, although I haven’t tried it myself! You can find a recipe and instructions on the Compostess blog.
Bokashi Bin Set by Pfctdayelise