Vermicomposting vs Bokashi – the new kid on the block

Sooner or later any compost enthusiast comes along this strange sounding method and wonders how this fits in with more widely known ways of food waste recycling. For worm farm keepers vermicomposting vs Bokashi will be one of their first questions. What can Bokashi do, worms can’t? Or vice versa, what can worms perhaps provide that Bokashi composting is not able to deliver?

In this article we compare them side by side so you can decide whether one or the other is worth adding to your composting tool box and what you need to do next.

What is Bokashi?

The roots of the process are believed to date back to ancient Korean or Japanese farming methods, although the technique we know today was developed as recently as the early 1980s, in Japan. Interestingly the word Bokashi has several meanings in Japanese, but has come to be understood as ‘fermented organic matter’ in the English-speaking world.

There is some controversy among purists as to whether Bokashi is a true composting method, as although the finished ‘product’ can be used as fertiliser, the actual process itself employs fermentation, rather than decomposition, making it more akin to pickling organic waste.

The fermentation itself takes place in a sealed container, most commonly known as a Bokashi bucket, and as such is an anaerobic – or airless – process. Whereas aerobic composting involves oxygen-breathing microbes breaking down the waste, the microbes necessary in Bokashi flourish in an oxygen-free environment and release the acids needed to break down the matter. 

What does the Bokashi method involve?

Bokashi itself is essentially an organic ‘accelerant’, consisting of a mixture of a base material, most commonly bran, some form of carbohydrate sugar (often molasses) for nutrients and the necessary microbes. These microbes are the same kind, or similar, as you would find in active yoghurt.

You can create this magic mix yourself, but the process can be complex, and time-consuming, so it is more commonly bought. 

As well as this vital ‘starter’, you will also need a container or bucket to create your compost. Again these are generally bought as Bokashi composting bins, but you can make your own, as long as you ensure it is airtight and has a way to drain the liquid that is produced.

For the first part of the process it is simply a matter of layering your kitchen waste (which can include meat and dairy trimmings) with the Bokashi mix in the container and sealing it. Allow 10-14 days fermentation to complete, draining off the liquid every day or so. This liquid can be used as garden fertiliser, but will need to be diluted first.

At the end of this period, you have your stage 1 pickled compost. But before it can be used, you need to complete stage 2. Your fermented matter will be too acidic to use as compost immediately, so needs to be buried in a fallow patch of garden to allow it to neutralise.

So how does Bokashi compare to vermicomposting?

There are similarities. Both essentially involve an enclosed system, both can be carried out (at least in part in the case of Bokashi) in a small indoor space and the zero-waste benefits are much-vaunted by proponents of each method.

Of course vermicomposting is an aerobic process, so your worm team will need oxygen – no sealed container for them!

Both processes are faster than traditional composting methods, and both produce a liquid during the process that can be used as fertilizer straight away. However, after around two weeks your worms will have produced compost that can be used immediately, whereas the Bokashi requires an additional couple of weeks before you have usable compost. This second stage also relies on having an area of outdoor space to bury your pickled harvest.

 So let’s look at how they compare practically

BokashiVermicomposting
Anaerobic processAerobic process
Probable initial outlay on bran mixture and Bokashi bucketProbable initial outlay on worm enclosure, bedding and composting worms
These can both be made yourself, but the bran particularly can be complex and time-consumingEnclosure and bedding can be made at home relatively easily
Can be done indoorsCan be done indoors
Small area required for stage 1, but must have access to some outdoor space for stage 2Only a small area required
Quantities of compost produced quite smallQuantities of compost produced quite small
Not suitable for garden wasteNot suitable for garden waste
All kitchen waste can be processed, including meat and dairy scrapsNot all kitchen scraps are suitable – no diary, animal fats or meat trimmings
Quicker than traditional composting – around two weeks for stage 1 and a further 2 weeks for stage 2Quicker than traditional and Bokashi methods – around two weeks for first compost batch
Odour-free if done correctlyOdour-free if done correctly
Each new batch will require addition of more Bokashi branYour end result will be more worms which can be transferred to a new wormery
Can be done all year roundCan be done all year round

So we can see that in many respects the processes have similar outcomes. There is the potential for a larger initial cost with Bokashi, and a slightly longer process, but both will give you usable, stable compost in a relatively short time, and after initial set-up, little effort.

For a fuller picture, we should also look at how these methods compare to traditional composting.

Traditional composting
Aerobic process
No initial outlay needed unless you wish to compost in a bin
Compost bin can be easily made yourself
Must be done outdoors
Suitable for all but the smallest gardens
Can produce larger volumes of compost
Suitable for garden waste as well as most kitchen waste (but not meat or dairy scraps)
Slower process
Risk of nasty smells if not maintained correctly, and vermin if wrong waste added
Easy to add to and build
Decomposition will slow or stop in cold weather

So we can see that both Bokashi and vermicomposting have advantages over traditional methods in terms of space needed, timescale, frequency of harvest and maintenance.

While not practical for disposing of garden waste, or large quantities of any waste, they are both effective ways of disposing of most organic kitchen waste, thus reducing your need to add to landfill. On this front Bokashi may have a slight edge, as you can dispose of animal and dairy scraps also.

Where a healthy worm farm streaks ahead of Bokashi is the latter’s need for the acid-neutralising second stage. If you have no outdoor space, this can present a problem.

You might choose to simply harvest the Bokashi liquid (known as leachate or sometimes Bokashi tea) for your own use, but then you are still left with the need to dispose of the fermented matter. Solutions could include borrowing a patch of garden from a friend to bury it in and sharing the resulting composty-goodness, or donating it to someone with a regular compost bin. 

For a proper comparison, we must also look at the usefulness of the end-product – essentially asking,

Bokashi – is it any good as a fertiliser?

We know the benefits of traditional compost, a method that has been used for centuries. We know the benefits of worm castings and leachate.  As a relatively new process, and therefore with fewer studies, Bokashi runs at a disadvantage. Potentially the jury is still out on the efficacy of its final product as a crop fertiliser in its own right.

Bokashi and worms – a match made in heaven?

Can you put Bokashi in a worm farm? Interestingly, many people are now starting to combine both methods, by adding their Bokashi ‘crop’ to their worm farm. It may seem counterintuitive to feed something with such a high acid content to works, but as long as care is taken to introduce the new food carefully, and keep a closer eye on your worms than usual, it does seem that they get used to their new food. 

With Bokashi being able to handle a wider variety of organic waste than a worm farm, combining the two is a very effective zero-waste option for all food wastes.

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