Bokashi - Phase II  Turning Your Pre-Compost Into Beautiful Black Gold!

Bokashi - Phase II Turning Your Pre-Compost Into Beautiful Black Gold!

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 “pre-compost”, since it needs to go through an actual composting process - or at least some other aerobic decomposition process - in order to be garden-ready!

Preparing to process bokashi pre-compost

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 pre-compost 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 pre-compost with lots of bulky, absorbent bedding and living materials (LMs) can help a great deal.

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.

Bokashi leachate

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:

Bokashi leachate with hemp tow and alder bark mulch

 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 Pre-Compost

As touched on, it will be very helpful to mix our pre-compost 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 pre-compost 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)

Bokashi pre-compost

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.

Bokashi pre-compost

We then added a generous amount of hemp tow…

Bokashi pre-compost with hemp tow

…before mixing everything together really well.

Bokashi pre-compost

Next, we added our very-well-aged alder mulch (had been sitting outdoors for many months)...

Processing bokashi pre-compost

…and once again mixed everything up really well.

Processing bokashi pre-compost

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 Pre-Compost to an Aerobic System

We happened to set up a new backyard composter not long before preparing our bokashi pre-compost 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 pre-compost 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 pre-compost 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.

Adding bokashi pre-compost to your backyard composting system

Once in place, we simply covered it over with a thick layer of hemp tow.

Adding bokashi pre-compost to your backyard composting system

Other Potential Ways to Get Your Pre-Compost Garden-Ready

Not everyone will have a backyard composter that’s ready to receive a pre-compost 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 pre-compost 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 Pre-Compost 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. 🙂

Super Simple Garden Burial

For those of you who don’t have any other composting systems, and don’t have an interest in setting any up, we still recommend the pre-compost mix preparation described earlier in this article, and the simple storage approach we just covered. Once you are able to access your gardens, you can dig a hole and dump the mix in. The longer it has been sitting (and breaking down aerobically) ahead of time, the less cautious you need to be in terms of proximity to your garden plants etc. (When adding in an area you plan to grow plants, always make sure it will be at least a few weeks before the plants are being added).

NOTE: Some people recommend basic burial of contents straight out of a bokashi bucket. While this may be technically “OK” - especially in areas away from your gardens, and when you are going to leave it sit for a long time - we don’t recommend it since it can have a negative impact on your soil biology.

Creating the conditions for the aerobic breakdown of finished bokashi bucket contents - even in a basic indoor tub system - is very easy, so we encourage you to take this extra step. This way you can reap even bigger rewards from the process, and sooner!

Summing Up

  • 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 pre-compost 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 pre-compost (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.

  • If you are planning to bury your pre-compost in the garden, it is highly recommended that you follow the mixing steps described rather than dumping it straight from your bucket.

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

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Bokashi Starter Kit - Single Bin
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