Bokashi offers us a great way to deal with a wide range of food wastes - including many that aren’t well suited for regular composting, such as meat and dairy - in an easy and hassle-free way. The big “catch”, however, is that the material that comes out of your bokashi bucket isn’t remotely close to being an actual compost.
This fermented mix is often referred to as “precompost”, since it needs to go through an actual composting process - or at least some other aerobic decomposition process - in order to be garden-ready!
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Back in early October we emptied out a finished bokashi bucket and prepped the material so it could be added to a new composter we had recently set up.
This article documents that process, and provides you with an overview of the ways you can turn your bokashi bucket wastes into plant-boosting, beautiful black gold!
The Big Idea
In order to help our precompost turn into actual compost, we need to expose the materials to plenty of oxygen and aerobic, decomposer microorganisms. These will help to convert the less-ideal anaerobic conditions and end products into more-favorable aerobic conditions and end products!
Mixing the precompost with lots of bulky, absorbent bedding and living materials (LMs) can help a great deal.
- Bedding materials are great for balancing the C:N of the rich bokashi wastes, soaking up excess moisture, and helping to improve airflow.
- Living materials can often offer some of the same benefits (depends on the LM you are using), but the big benefit they offer is helping us to inoculate our anaerobic precompost - and the system as a whole - with loads of those aerobic decomposer microbes that are so valuable for helping us finish off the composting process!
Step #1 - Liquid Drainage
In order to assist the mixing step (Step #2), it’s ideal to first drain off as much of the liquid from the reservoir - and the materials themselves - as you possibly can. Position a small bucket or other container below the spigot, open it up and away you go. It helps to tilt the bokashi bucket forward during this process, and you may even want to mix the materials in the bucket around to help more liquid drain down from above.
Apart from the potential uses for the liquid mentioned in our introductory bokashi article, you might also consider keeping it for use in fruit fly traps (it draws them in like a magnet) or soaking it up with bedding and living materials, and then just adding this solid mix to a regular composting system.
We tested this second strategy ourselves by mixing the large amount of drainage liquid from our bucket with lots of hemp tow and older alder mulch.
This is what we ended up with:
This sweet-smelling mix was then added to an outdoor vermicomposting system, and within a day or two the worms were concentrating below it and even moving into it, surpassing even our optimistic predictions!
Step #2 - Mixing the Precompost
As touched on, it will be very helpful to mix our precompost with lots of bulky, carbon-rich bedding and (ideally) some form of living material so as to help accelerate the aerobic composting/decomposition process.
There are a wide range of different materials you can use for this - such as shredded cardboard, coco coir, mulched leaves, even hardwood stove pellets (among others) as your bedding, and old manure, composts, or really decomposed leaves (among others) for your living material(s).
We used the same hemp tow and well-aged alder mulch that was used to mix with the drainage liquid since we had plenty on hand.
The finished precompost should always have a fairly pleasant, almost sweet pickle-y smell to it, and it often has a light coating of white fungal growth over the surface. (Be sure to check out our “Bokashi Gone Wrong” blog post to learn more about the signs of a faulty process/system)
When you dump it out, don’t be alarmed if a lot of the material from the bucket looks very similar to when it was added. In a sense, the fermentation process breaks down the organic matter in some ways, while also preserving it in other ways!
We decided to split our bucket contents between two mortar trays to make the mixing process even easier and more effective.
We then added a generous amount of hemp tow…
…before mixing everything together really well.
Next, we added our very-well-aged alder mulch (had been sitting outdoors for many months)...
…and once again mixed everything up really well.
NOTE: There is no exact amount of bedding and living material you need to add. The key is simply to add enough to soak up all remaining liquid (there should be no pooling in the bottom of the mixing tub), and to end up with a nice bulky/fluffy mix with a good distribution of beneficial decomposer microbes (what LMs are loaded with).
Step #3 - Adding Precompost to an Aerobic System
We happened to set up a new backyard composter not long before preparing our bokashi precompost mix, so this provided us with the perfect spot to deposit it.
Even with the sort of careful mix preparation described in Step #2, it is still important to err on the side of caution if you happen to be adding the material to a system containing composting worms, since the various end products of the fermentation process - such as organic acids - are highly acidic and can be harmful to them.
Knowing ahead of time we’d likely be adding bokashi precompost materials to this system, we made sure to add our starter worms much further down, in the below-ground zone set up before the actual composter was even put in place.
Just generally, separating your worm zone from your bokashi zone - using various layers of bedding and living material - is all that’s needed. The idea here is to allow the worms to access the new materials on their own terms, rather than forcing it on them. The good news is that this may actually happen a lot more quickly than you think (especially if your precompost has been mixed with a lot of high-quality living material).
Our own souped-up bokashi deposit was added up at the very top of our newly set-up composter.
Once in place, we simply covered it over with a thick layer of hemp tow.
Other Potential Ways to Get Your Precompost Garden-Ready
Not everyone will have a backyard composter that’s ready to receive a precompost mix - especially during the winter (when a bokashi bucket is actually most useful for a lot of people).
In this case, you have the choice of either leaving your bokashi bucket(s) to sit until you are prepared (and conditions are favourable) to use the material outdoors, or you can get a jumpstart on your aerobic breakdown efforts, using more basic methods indoors. The advantages of the latter approach - and why we recommend it - are that you will: 1) free up your bokashi containers so they can be used again right away, and 2) you will get the ball rolling with turning your precompost into something that can be used in your garden!
Assuming you still have access to a decent amount of bedding materials (and hopefully some living material) you should be able to make your bulky mix, similar to how we described earlier. In this case, though, we recommend either mixing in even more bedding, and then leaving it to sit in the container you mixed in it (ideally with some form of lid and some air holes), or dumping it - again, referring to a prepared mix, not straight from the bucket - into another container that already has some dry, absorbent bedding sitting in the bottom of it (once again, ideally adding a lid with some air holes as well).
This way the mix will still be able to start breaking down aerobically while you (hopefully) get your bokashi bucket going again for another cycle!
Can the Precompost Mix be Added to an Indoor Worm Bin?
Absolutely! Just make sure it is a mix (made the way we’ve outlined), and only add very small amounts at a time, until you are sure it is going to be well-received by the worms. This is one of the benefits of having a storage bin for the mix to sit in - there’s no real rush to put it to use, and, like a fine wine, it will only get better over time. 🙂
On a related note, you may also want to consider…
The “Soil Factory” Method
A very simple alternative to the recommendations outlined so far in this article - especially well suited for anyone who has limited bedding / living material available - is what’s known as the “Soil Factory” method. This can work well in either an outdoor pit or in a ventilated bin - the latter being a better option in our opinion, especially during colder times of year.
NOTE: Drainage holes, while not necessary, can also help with moisture management. Just make sure you also have a catch tray underneath if keeping the bin indoors.
If you don’t happen to have access to good garden soil (should be lightweight and loamy, if possible), a bagged organic potting soil can work too - ideally with at least a little bit of living material mixed in (even a handful of soil from a potted plant would help).
Getting your Soil Factory up and running is very easy. You can think in terms of 3 equal layers: 1) soil (bottom), 2) bokashi precompost (middle), and 3) soil (top). So your final ratio should be about ⅔ soil and ⅓ precompost (actual volumes will depend on the total amount of precompost you have to work with).
Erring on the side of even more soil (and/or other bedding/living materials) than what is suggested is always better than adding too little, since the goal is to transition the decomposition from anaerobic to aerobic. This is especially helpful if you decide to mix everything up (not necessary), and when your precompost is very wet.
Adding a decent dusting of a calcium-rich rock dust (like our pH Buffer/Grit) or agricultural lime over your precompost layer(s) can also be helpful for balancing the acidity of the material, but isn’t mandatory.
Once set up, leave your Soil Factory to sit for at least 2 to 4 weeks before adding the material to your garden or another composting system (e.g. worm bin).
UPDATE: If you would like to learn about our own “3-Zone” Soil Factory approach (and just generally learn more about the method), be sure to check out “The Bokashi ‘Soil Factory’ Method”!
Super Simple Garden Burial
For those of you who do have garden access (e.g. during warmer times of year), and almost zero interest in getting “fancy” with your Phase II efforts, a very basic burial method is still an option. That said, we still highly recommend some form of layered approach using the soil you excavate from the hole.
Start by digging a hole, either in one of your gardens (where you won’t be planting for a few weeks), or in some other area of your yard. You should be ok with a depth of about 1 ft. Next simply alternate layers of bokashi precompost (of about an inch or two) with layers of the soil you excavated from the hole, until you’ve completely used up the contents of your bokashi bucket. Make sure the final layer is a nice thick layer of the soil.
This deposit should be left for at least 2-4 weeks before anything is planted in the immediate vicinity.
Summing Up
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Bokashi fermentation offers us an amazing, convenient way to divert a wide range of less-compost-friendly food wastes from the landfill, but it does require some form of aerobic decomposition process in order to be converted into a material that is beneficial for your plants.
- Both the solids as well as the bokashi leachate can be mixed with bulky, absorbent bedding and living materials to create mixes that are much better suited for composting systems or burial. (The liquid can also be used in a variety of other ways)
- The resulting mix should be moist and bulky, with no pooling of liquid in the bottom of the mixing container.
- If you are adding this (or any other) bokashi precompost to a system with composting worms, always make sure there is a lot of other material between the worm zone and the deposit, or add very small amounts at a time.
- If you plan to simply let your precompost (with bedding and LM) sit, mix in even more bedding, or add it to a bin that already has bulky, absorbent bedding in the bottom.
- A super simple alternative is the “Soil Factory” method, where you sandwich thin (1-2”) layers of bokashi precompost in between thicker (4-6”) layers of organic potting soil, and leave to sit for at least 2-4 weeks
- If you are planning to bury your precompost in the garden, it is highly recommended that you at least alternate layers of precompost with layers of the soil you excavate from the hole. This should be left for 2-4 weeks before planting nearby.
Helpful Related Resources
Bokashi - A Simple, Effective Method for Beneficial Kitchen Waste Conversion!
Bokashi Gone Wrong
What is “Living Material”?
Bedding - The Most Important Material in Your Worm Bin?
Setting Up Your GeoBin for Worm Composting Success
Recommended Products
Bokashi Starter Kit - Single Bin
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