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.
What is bokashi composting?
Bokashi composting isn’t actually composting in itself. 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 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 aerobic environment, that is in an airtight container. The Bokashi 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 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 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.
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. 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 making compost. You can see it at ‘What does lime do to compost?’.
About bokashi soil factories
The Bokashi method will immerse everything in acid and effectively ‘cleans’ the waste of anything harmful.
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?
The more of this you use the better but it’s wasteful to be too excessive. As a general rule aim to add about 2 tablespoons to every one-inch depth of waste in a standard Bokashi bin. Sprinkle it around for even coverage and lightly stir it into the waste to get it working throughout as quickly as possible.
You will know if you aren’t using enough Bokashi bran because there will be a distinctive foul smell. You will also notice a selection of bright coloured moulds appear on the surface of the waste.This is an indication of stagnation rather fermentation. In the event of this be prepared to add more Bokashi bran, this is something that you will develop a feel for over time.
Without a full fermentation of the waste you will probably see evidence of vermin visiting the the compost bin because some of the food waste is attractive to them.
To get the best out the Bokashi method chop any large items of waste. The smaller the particles of waste the more surface area there is available to the Bokashi micro-organisms.
Use the tools provide with your Bokashi bucket kit to press down the waste to remove as much air as possible and securely fit the bucket lid to keep air out. This is an anaerobic method of fermentation.
How long does it take for Bokashi to break down?
If you are adding the optimum amount of Bokashi bran for the waste involved, the waste material is chopped or particulate enough, you’ve done everything needed to remove excess air then you can expect full fermentation in 2 to 3 weeks. This means that when you load in the last deposit into the Bokashi bucket, you need to put the lid on and leave it for, ideally, 3 weeks before you can empty the bucket and start again.
How do I use my Bokashi?
When you empty your Bokashi bucket there are a couple of choices. You can load it into a compost bin with layers of soil as described earlier. This will give you the Bokashi soil factory.
The other options include:
Dumping it in a compost bin and just leaving it there for as long as it takes to convert into compost.
Loading it into a compost tumbler giving it the advantage of regular aerating which will accelerate decomposition.
Digging a trench in a managed part of the garden where you want to grow things and bury it.
If you go for any of these options it’s worth mentioning, again, that using hydrated lime will make a huge difference. Remember that the contents of the Bokashi bucket will be acidic because of the fermentation process. The hydrated lime will neutralize this acid allowing for effective decomposition.
You could put the entire production from the Bokashi-bucket system in either a conventional compost bin or compost tumbler, with the addition of hydrated white lime. To help you chose which type of composter to use, we have a post that looks at static or tumbler style bins. You can see it at ‘Tumbler composter vs bin’.
Bokashi in winter
Temperature can play a big part in the fermentation process. If you are culturing your Bokashi bucket indoors there shouldn’t be a problem because the fermentation process works best at room temperature. If you have it outside then you may need to cover it with adequate insulation against cold weather. In freezing cold weather it is likely the the whole process will stop.
The same applies, although to a lesser extent, if the weather is very hot.
The ideal place for your Bokashi bucket is in the kitchen where the temperature is likely to be suitable for the system and constant.
Can you give Bokashi to worms?
Do not expect worms to be interested in pre-compost material that has come straight out of a Bukashi bucket. They won’t go near it. The best way to approach this is to place it in a basic plastic bucket with no lid but just a loose cover so that air can get in.
Add a generous sprinkling of hydrated lime and mix it in, then wait and watch. After about one week you should see evidence of the acid ph level rising to a neutral level. You should see a variety of mould and fungi appearing on the surface. This won’t happen if there is a high level of acidity. If you don’t see mould after a week then you probably need to add more hydrated lime.
The mould is food for worms they graze on it because it’s easy for them to bite at and digest. So when you see this you can safely assume that the worms will benefit from it and you can feed it to a wormery knowing that they will dig their way in.
Because of the fermentation process that Bokashi pre-compost material has gone through, the worms will find it very easy to consume. It will be soft and moist to the worms. They will quickly convert this to worm-casts.
Bokashi composting in an apartment
A Bokashi bucket takes up very little space and, because it involves a sealed container, there is little risk of being troubled by bad smells. The risk of smells is kept to a minimum if you stick to a regular routine of draining off the liquid.
The question is, what do you do with the contents of the bucket when it’s time to empty out? One option is to run a layered wormery and feed the Bokashi fermented material to that but you will need to treat it with hydrated lime as we’ve already discussed.
Assuming that you have no garden area of your own at all then another option is to find someone who has a garden and let them have the benefit of it. Anyone who has a garden and knows anything about growing anything will appreciate the value of what you have.
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.
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’.
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.