Bokashi soil factory – see what to do with Bokashi waste

Go to Home Page

Bokashi soil factory

Also: What is bokashi composting?

How much Bokashi bran to use?

How long does it take for Bokashi to break down?

How do I use my Bokashi?

Bokashi in winter

Can you feed Bokashi to worms?

Bokashi composting in an apartment

A Bokashi soil factory is a very simple arrangement and easy to do. The Bokashi treated waste is placed as a layer in a conventional compost bin on top of a layer of good quality soil. The Bokashi treated waste is often referred to as ‘pre-compost waste’. Another layer of soil is put on top of the waste. When more Bokashi waste is available you have a ready made place to put it, on top of the soil as the next layer.

This is then covered with another layer of soil. You just have to repeat the process until the bin is eventually filled. You will find that long before the bin fills, you will be able to start extracting ready to use compost from the base of the bin. It will take about 4 to 6 weeks for the Bokashi treated material to convert into anything usable.

Set up a bokashi soil factory

You only need a basic compost bin.

Bokashi soil factory_01

What is bokashi composting?

Bokashi composting is the fermentation of food waste in an air-tight container. This is more commonly known as anaerobic digestion. The Bokashi composting system will generate acidity that will neutralize most, if not all, potentially dangerous pathogens that are associated with decomposing food.

Bokashi composting isn’t actually composting. You need to see it as the first stage in a complete composting process. You have a constant supply of green kitchen waste coming to you, this is a given. When you use the Bokashi composting method of waste disposal you subject this waste to a fermentation process.

The fermentation occurs as a result of adding specially selected yeasts and bacterial pathogens which function in an anaerobic environment, that’s in an airtight container. The Bokashi composting process doesn’t need oxygen.

As the fermentation occurs a selection of lactic acids are generated which actually preserve the waste. You may ask ‘why preserve kitchen waste when we want to break it down into compost?’.

This is a relevant question. By putting Kitchen waste through the Bokashi composting process the acids that are generated will kill any potentially harmful pathogens which may be found in parts of the collective waste.

The focus here can be on cooked meat waste.

We are being told that we mustn’t put cooked meat waste in a conventional compost bin because of the risk of disease and this is right. When this type of material is thrown into a compost bin we have no control of what happens next. In most composting cases it will rot down quickly and disperse but there is a risk that it won’t and somehow emerge to affect the wider environment.

The Bokashi method will immerse everything in acid and effectively ‘cleans’ the waste of anything harmful.

Another reason why people choose the Bokashi composting system is that there is less smell involved compared to the aerobic method of conventional composting. 

There is one thing that you can do that will make it safe to put cooked meat waste in any conventional composting system and that is to add hydrated white lime. This will reduce any acidity to a point where decomposition will happen quickly. This method is the exact opposite of Bokashi composting.

The lime will deter rodents from exploring and removing anything that they may fancy. We have a post that explains how using hydrated white lime can help with conventional composting. You can see it at ‘What does lime do to compost?’.

Hydrated lime must not be used in the Bokashi composting process. Here, we want the acid level to be as high as possible.

The Bokashi composting process will generate a bonus. Unlike conventional composting where moisture escapes as water vapour, all of the moisture in the food waste is retained in the Bokashi composting bucket. The liquid can be drained from the bucket and can be used as a fertilizer but you need to be aware that it will be very acidic. 

Specially made Bokashi composting buckets will have a tap at the base for draining the liquid away.

Bokashi bin

So If you want to give the Bokashi method a go, you really need to set yourself up with a Bokashi bin. These are very easy to use. A Bokashi bin consists of a bucket with a tight-fitting lid to keep the air out. It is possible to make your own container for this but be aware that the process generates an effluent liquid which must be drained off to avoid bad smells. This is best achieved by installing an outlet tap or spigot for ease of draining.

It may be easier to buy a ready-made kit. The kit will include the bucket with the sealable lid, the outlet spigot or tap and tools needed for the Bokashi process.

You will also need the Bokashi bran which the dried form of the Bokashi culture. This is what you will be adding to the waste

What is in Bokashi?

Bokashi bran is what you will be using in a Bokashi system. The bran is the inert medium that the Bokashi culture is absorbed onto. The Bokashi culture is derived from a fermentation process that selectively generates the specific yeasts and bacterial microbes.This is also known as EM ( effective micro-organisms). The bran portion is often a bi-product of the seed milling industry. This may be from wheat or rice. Dried leaves and sawdust can also be used.

After being absorbed on to the medium, the mix must be dried down to a storable moisture level. It is made available to you to use in convenient sachets of Bokashi bran. This is safe to handle.

How much Bokashi bran to use.

Knowing how much Bokashi bran to use will secure success or a smelly failure. As an easy guide, you need to sprinkle 2 tablespoons of Bokashi bran on every inch of depth of food waste that you add to your Bokashi composting bucket. Er on the side of using more Bokashi bran than less.

Bokashi bran can be used to process large quantities of food-waste. If we take a round figure of 1000Litres (250gal.) of food-waste, this would require approximately 40Kgs (88Lbs) of Bokashi bran. For large quantities to work efficiently you would need to add the Bokashi bran as you build layers of  food-waste.

When you first set up a Bokashi bucket system, you will need to know how much Bokashi bran to use with your first consignment that’ll be going into the bucket. All the advice that I can find has it that it’s better to go for overkill and add more rather than less.

If adding 2 tablespoons of Bokashi bran is enough for a 1 inch depth of food waste when you’re making regular additions, then you would be safe if you double this amount at the startup stage.

There are clear indicators that will show that you’ve added enough Bokashi bran. These will include a yeasty smell coming from the Bokashi bucket when you lift the lid. You may also see a white mould appear on the surface; this doesn’t always happen.

If there’s a foul smell accompanied with a blue and green mould on the surface, this can be taken as a failure of the system due to not enough Bokashi bran being added.

The Bokashi bran contains the microbes that start and maintain the fermentation that we need for food-waste to break down. Your Bokashi bran needs to be relatively fresh. If it’s been hiding in a cupboard for some time, you need to check the smell of it. 

If there’s a smell of ammonia coming from Bokashi bran that’s been around for a while, this would indicate that it’s no longer of use. It can’t be relied upon to work for you as an effective Bokashi bran when added to food-waste in a Bokashi bucket.

Bokashi bran has been known to store for up to 2 years. This can only be possible if you store it in an airtight container, keep it out of direct sunlight and maintain it at room temperature. To have any chance of long-life storage the Bokashi bran that you have, will need to be of good quality.

If you have Bokashi bran that you know you won’t be using for a while, make sure that it’s completely dry. The slightest amount of moisture in Bokashi bran will encourage it to start working within itself. If this happens in storageyou won’t know that it’s happening.

A lot will depend on whether your Bokashi bran was acquired from a store or whether you made your own mixture. Store-bought Bokashi bran tends to be fully dried. Professional Bokashi bran suppliers will have the facilities to make sure that it’s dried to a constant.
When you make your own mixture of Bokashi bran, you can’t be sure that you have dried it enough. This isn’t a problem. You just need to use your home-made Bokashi bran a bit faster than anything that you buy.

How long does it take for Bokashi to break down?

You need to allow 14 to 20 days, after your last addition of food-waste to your Bokashi bucket, for it to break down. Earlier additions will have had time to break down fully. It’s the last addition, which will fill the Bokashi bucket, that needs time to break down before you can use it.

Provided that you have added enough Bokashi bran when you make your last addition of food-waste to the Bokashi bucket, there are unlikely to be any limiting factors that will affect the outcome.

When the required time has passed, you should have a batch of accumulated food-waste which the Bokashi bran has worked on to the fullest extent. It will not be able to break down any further. 

There are things that you can do to help the Bokashi mass in the bucket to break down. It’s important to extract as much air from the food-waste material as possible. Bokashi composting is an anaerobic process. 

Every time you add fresh food-waste to the Bokashi bucket, you need to press the fresh layer down to extract air. Then sprinkle the measure of Bokashi bran that you need, on top of the fresh layer. 

Some suggest that you could use an old plate to apply even pressure over the layer of food-waste that you’ve added. Then add the Bokashi bran. The plate could be left on the surface of the Bokashi bran and food-waste to maintain continued pressure.

There is an argument that drawing off liquid from the Bokashi bucket will help the microbes that affect the fermentation of the fermenting mass. The liquidity of the mass as a whole should, in theory, help with the mobilising of the required microbes. This would help to ensure an even fermentation throughout the mass in the Bokashi bucket. The removal of liquid from the base of the Bokashi bucket is more about providing capacity for more solid fresh food-waste. 

How do I use my Bokashi?

If we’re referring to Bokashi as being the Bokashi bran preparation and how we use it, there is only one use for it that will have any meaningful effect. The aim is to efficiently break down food-waste. By using Bokashi bran we can break down food-waste in a confined space through fermentation.

In the confined space of a sealed bucket, food-waste will succumb to the full force of the fermentation process that Bokashi microbes provide. The important point to note is that you must use enough Bokashi bran for there to be a viable fermentation. 

If you use more Bokashi bran than is actually needed for the volumes of food-waste involved, the extra portion will effectively go to waste. Once the maximum level of fermentation has been achieved and the acidity level that goes with it, adding yet more Bokashi bran will have no extra effect. 

You need to be mindful that the Bokashi process generates acidity wherever it succeeds to create a fermentation.

Some people are suggesting that using Bokashi bran in a conventional composting system would improve the process. Here, we’re looking at an aerobic decomposition of food-waste as opposed to the anaerobic confines of a sealed Bokashi bucket.

The aerobic route of turning food-waste into compost requires that we aim for a low level of acidity. Acids will preserve, rather like pickling. In conventional composting we want food-waste to rot as quickly as possible. 

If you use your Bokashi bran on a conventional aerobic composting mass, you may achieve some fermentation. If this happens, you will also generate acids which will preserve items of food-waste which need to rot down.

The point is, you should only use your Bokashi bran for processing food-waste in a sealed Bokashi bucket. Don’t attempt to use your Bokashi bran in a compost bin because it will create a conflict between the non-acidity that aerobic composting requires and the acidity that a Bokashi fermentation will try to generate.

Bokashi in winter

Bokashi treatment of food-waste will be a problem in winter if your Bokashi bucket is subjected to very cold winter-temperatures. The Bokashi system involves fermentation. This can’t work at low temperatures. A Bokashi bucket maintained at room temperature will allow fermentation to happen.

If your Bokashi bucket needs to be outside during the winter months and you want to continue adding fresh food-waste to it, you need to apply layers of insulation before any cold winter-temperatures begin to take any effect. 

With careful preparations, Bokashi in winter can be as effective as Bokashi being used at any other time of the year. Depending on where you are in the world, you may be lucky. Not everywhere gets a cold winter. Where we do tend to have a cold winter there’s always the chance that the winter-months may be mild. In this case Bokashi in winter can work for you seamlessly through the year.

If you leave a Bokashi bucket outside during winter it may become so cold that the fermentation process slows down or, perhaps, stops completely. This won’t be a disaster.

Winter won’t go on forever. The Bokashi bucket will go into a suspended state during really cold winter weather, while it lasts. When the weather changes and the air warms up, the temperature in the Bokashi bucket will rise and normal fermentation will be resumed.

It won’t be just Bokashi in winter that will be affected by a drop in temperature. A conventional compost bin or heap will often go into a dormant state during the winter months. Very often a large mass of compost will continue to decompose in the innermost regions as this part will be insulated from the winter-cold by the outer layers.

The winter time is when we can expect most things in the natural world to go into a degree of hibernation. Your compost bin or Bokashi in winter will be no exception.

Can you feed Bokashi to worms?

If you try to feed Bokashi to worms, they will move away from it. Anything that comes out of the Bokashi bucket will have been fully fermented and will be highly acidic. Feeding this to worms won’t be a problem to them provided that they can escape into a non-acidic mass.

This isn’t to say that you can’t feed Bokashi to worms at all. The high level of acidity needs to drop to the point where it’s near a neutral point. This may take some time. 

Unless you’re watching proceedings in your wormery all the time, you won’t actually know how long it will be from the point when you feed Bokashi to worms and the point at which they actually start to feed on it. 

Worms won’t consume Bokashi waste straight away

Some people seem to have the idea that worms don’t dive straight into Bokashi that’s being used as feed directly from the Bokashi bucket because they aren’t used to it.

Worms are very sensitive. If the conditions aren’t agreeable to them, it can make the difference between a very strong population of worms and no worms at all.

Worms are delicate and fussy

Worms have very thin skin. Worms are delicate. This is why worms are, usually, only found underground or in a mass of rotting organic material where the moisture level is high enough, the acidity level is low enough and there is a food source that’s immediately digestible to them.

So, worms won’t identify fresh Bokashi waste as feed. They will assess it and move away from it because of the high level of acidity. They will come back to it when the acidity level has dropped. In the fermentation process, Bokashi waste has been fermented and become preserved. 

When air can get at fresh Bokashi, it will begin to change but until those changes start to occur, fresh Bokashi treated food-waste will be just like fresh food to worms.

Everything needs to be rotten for worms 

Worms will only ingest rotten organic material. They are prepared to wait as long as it takes for any organic material to rot down. Rotten, wet organic waste can be easily digested by worms. 

Some people seem to think that, because fresh Bokashi is wet and soft, this type of material can be ingested and digested by worms in the same way as rotten material. Fresh Bokashi will need to rot enough for worms to be interested. 

There is one thing that you can do to accelerate the rotting of fresh Bokashi treated food-waste. Add hydrated white lime. This is a powder that can be sprinkled over the Bokashi treated material. It will reduce the acidity and thus remove the preservation factor that any acidity provides.

With the acidity reduced, the Bokashi waste will begin to rot. This process will begin with mould appearing on the surface of the Bokashi treated waste. The worms will graze on this mould. As the mould works its way through the Bokashi waste the worms will be able to follow through and consume the now rotten material.

Hydrated lime will help worms digest organic waste

White hydrated white lime is safe for worms and it will allow for decomposition to commence earlier than it would have done. Worms can make use of the particles of white lime. As worms digest soft rotten organic waste, the fine particles that make up white lime, help to grind and break down any ingested material.



Bokashi composting in an apartment

Bokashi composting is a simple way of processing food-waste. It can easily be done in the confines of a small apartment. Note that this isn’t actually composting in the fullest sense. The Bokashi system is all about processing and containing, for now. It will have to be fully disposed of later.

Making conventional compost in an apartment isn’t going to be an option. A compost bin needs to be outside in the open air. Composting food-waste in the traditional style generates smells, liquid run-off, flies and if you’re really unlucky, rodents. And dare I mention, possibly, snakes. None of this would be welcome in your apartment.

In the smallest of apartments it should be possible to find a place where you can hide a Bokashi bucket. They hold about 20 Litres and, until you’ve got the thing anywhere near full, you can move it if you want it somewhere else in your apartment. A Bokashi composting bucket is a sealed entity. You only need to take the lid off when you add fresh food-waste together with the required amount of Bokashi bran. 

So, the only time that you’re going to expose your apartment to any possible smells will be when you lift the lid. This needn’t be a bad experience. If you use enough Bokashi bran, the food-waste will break down as it should and there will only be a yeasty smell.

The Bokashi system of processing food-waste doesn’t involve worms. Most recommendations out there are for people, in apartments, to feed food-waste to a wormery. This may be an option for some. A wormery won’t take up much more space in an apartment than a Bokashi bucket.

A Bokashi bucket isn’t a wormery. The fully fermented contents of a Bokashi bucket can be fed to a wormery but you need to mix it with hydrated white lime and leave it for a couple of weeks. Then you could feed this into a wormery system. 

As the material from the Bokashi bucket begins to rot, the worms will take an interest. This double process may interest you but it will ultimately depend on how much room you have in your apartment.

Having a Bokashi bucket tucked away somewhere in your apartment is a highly convenient way of disposing of fresh food-waste. It will take any type of food. The microbes that emerge from the Bokashi bran don’t discriminate. 

Just remember that whatever is food to us will be food to something else. Bokashi microbes will break down everything that goes in the Bokashi bucket provided that it’s food.

Other than lifting the lid and adding food-waste together with the required measure of Bokashi bran, the Bokashi bucket needs very little attention. It can sit in an out-of-the-way position in your apartment for months, until the day comes when you need to empty it.

You can drain away some of the liquid that will be generated from the Bokashi process. This will help to make more room for fresh food-waste. If you have house-plants in your apartment, this liquid can be used as a plant-food. Be aware that the liquid will be acidic. 

One really effective way of reducing the acidity of the liquid would be to mix in some hydrated white lime. This will neutralize the acid and the lime won’t adversely affect non-acid loving plants.

Then we come to the question of what to do with the entire contents of the Bokashi bucket when we reach the point where it’s completely full. You may need to store your food-waste elsewhere for one or two weeks to allow the last addition that filled your Bokashi bucket to break down.

You need to plan for this moment in advance. If all you have is your apartment and no garden facility at all, then, you need to find someone somewhere to help you out. 

There should be a keen gardener out there somewhere who doesn’t live in an apartment who would appreciate the value of what you have. If you can dispose of the fermented waste from your Bokashi bucket this way, I think you will find it the simplest and least complicated way.

However, if you have a reasonably sized balcony attached to your apartment, you may be tempted to grow enough vegetation in boxes or pots, to be able to make use of it yourself.

You will need to mix some hydrated white lime with it to neutralize the acidity generated by the Bokashi fermentation process. This mixture will need to be left in a container that has plenty of air access because it needs to rot down.

The smells from this shouldn’t be too much of a problem but you won’t want it in your apartment. Find a place on the periphery of your balcony. Be prepared to wait for a month or two for the mixture to rot down enough to be able to use it for growing plants.

Maggots in Bokashi bin

If you ever lift the lid of your Bokashi bucket and see evidence of maggots or lots of flies then this means that you are failing completely at your attempt to make Bokashi compost. It simply means that you aren’t using anything like enough Bokashi bran and because of this the fermentation isn’t happening or, if it is, it’s happening at a very low level.

With a good fermentation of the material there will be a high level of acidity which means that maggots just won’t survive in it. See Maggots in my Bokashi bin to find out more.

Bokashi rats

This is another area where the high level of acidity deters any interest from pests including rats. Provided enough Bokashi bran is added in the fermentation stage there won’t be anything in the resulting compost that will be any use to them. If you know that there are rats in your immediate area there are things you can do to tackle the problem. See the post ‘How to deter rats from the garden.

Bokashi humanure

The idea of using the Bokashi system on human waste worries me. Here we are looking at composting toilets. If you add Bokashi bran to the growing contents of a compost toilet you will get a fermentation process. Depending on your outlook on life this may be something you would be proud of.

Let’s be clear, the adding of Bokashi bran will cause a fermentation that will generate acids which will effectively preserve rather than break down the waste. It will also generate liquid effluent which will need to be drained away, that sounds like fun. If you don’t drain it away there will be a smell.

So I say leave the Bokashi out of the composting bog for everyone’s sake. Instead use hydrated lime as this will do much to accelerate the decomposition of human waste. See our post ‘Composting toilet’ to find out a little more about how to set up a compost toilet.

Go to Home Page


 Compost flies  Find out about 'Brown' material in compost. What to put in compost bin to start. 

 Can you use compost for growing vegetables? Grow potatoes in a bin. Composting tea bags.

Hot composting in winter. Compost on clay soil Tumbler composter vs bin



Comments are closed, but trackbacks and pingbacks are open.