Backyard composting and vermicomposting tend to get the lion’s share of attention when it comes to composting at home, but there’s a another method that tends to fly under the radar a bit more; a method that offers some unique advantages over the other approaches.
That method, of course, is bokashi!
Often referred to as “bokashi composting”, bokashi actually involves an anaerobic fermentation process.The roots of this method can likely be traced back anaerobic decomposition techniques used in Korea, but it was Dr. Tiruo Higa, an agricultural researcher from Japan, who developed the official bokashi method in the early 80’s. A key part of the process was - and still is - the use of a diverse mix of bacteria and yeasts that Higa called “Effective Microorganisms” (EM).
So what are some of the key perks of bokashi?
- More Waste Options - Maybe the biggest bokashi advantage is that you can process a much wider range of kitchen scraps, including quite a few materials thought of as composting “no no”s. Meats, dairy, seafood wastes, even bones, can all be added to a bokashi system - making kitchen scrap collection and handling a lot simpler.
- Easy Set-Up & Management - Unlike more typical composting methods, where you might need to balance materials properly, monitor temperatures closely, turn and mix the contents (in the case of thermophilic composting), or care for worms (in the case of vermicomposting), with bokashi, there is relatively little you need to do to start up and maintain a system.
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Fewer Hassles - Foul odours and pests can both be common issues - and common reasons for people to throw in the towel - with regular composting systems, especially when not properly managed. Both of these are very unlikely with a bokashi system.
- Faster - The bokashi process itself, and likely even bokashi plus the waste stabilization phase can be faster than regular composting alone.
This brings us to a very important caveat relating to bokashi:
The material that comes out of your bokashi bucket, often referred to as “pre-compost”, is not compost, or anything that can be immediately used as a valuable soil amendment. It will need further stabilization in a much more aerobic environment.
We’ll look at some different options a bit further along in this article, but first, let’s look at…
Getting Started with Bokashi - Supplies
There are really only 3 things you need to get going with your first (or next) bokashi system.
- A supply of biodegradable kitchen scraps.
- Some type of vessel that can be tightly closed.
- A special bran mix that has been inoculated with EM.
Let’s look at each of these in more detail.
Waste Materials Well-Suited (and Not So Well-Suited) for Bokashi
As touched on, probably the biggest perk of bokashi is the ability to add pretty well any organic (biodegradable) kitchen waste. In other words, all the usual kitchen scraps we collect for composting, plus meats, dairy, seafood wastes…even bones.
That being said, it is still important to think ahead, and remember that these are materials that may end up in a composting system, and will more than likely eventually end up in your soil. So you will still likely want to limit excessively salty and/or oily foods.
Apart from these, some other materials not well-suited for bokashi include:
- Moldy foods
- Liquid wastes
- Bulky yard wastes
- Livestock manures
- High-carbon materials (“browns”)
Choosing (or Making?) Your Bokashi Bucket
A typical home-scale bokashi bucket should have a volume in the 15-30 litre range. It is ideal to have a set of 2, if possible, so you can continue the process once your first bucket is full. Bokashi buckets should always have a tightly-fitting lid, so as to keep air out when closed.
Right off the bat, some people will naturally wonder if they can make their own bokashi bucket.
We are all for DIY composting approaches - but this is definitely one case where we highly recommend purchasing manufactured bins. They will come with a false bottom floor, to keep the waste materials separated from the leachate that accumulates, and will also have a spigot so you can drain this liquid out regularly.
EM Inoculated Bran Mix
We take a similar stance with the EM-inoculated bran mix as we do with bokashi buckets. Yes, you can in fact make this bran mix yourself (and one of our team members has done so in the past), but we feel it is far easier to simply purchase the mix from a supplier. The good news is you really only need a sprinkle or two any time you add new scraps, so even a modest supply of the bran should keep you going for a while! As an example, the 1 kg bag of EM bran that we sell should be enough for 5 full bokashi cycles!
On that note, it’s time to talk about…
Using Your Bokashi Bin - Step By Step
Ok, you have your supplies and you’re ready to go. Now what?
Well, the good news is that getting your bin going couldn’t be easier!
Here is the 5 step process:
STEP #1 - EM Bran Starter
Sprinkle in a small amount of your EM bran over top of the false bottom floor.
STEP #2 - Add Your Deposit of Scraps
Add the kitchen scraps you have in layers of 1” to 2” at a time.
NOTE: You can add more than 1-2” per (total) deposit, but in between each 1 to 2” layer, you’ll want to…
STEP #3 - Lightly Coat the Scraps with EM Bran
There is no exact quantity of bran mix you need to add every time. A simple guideline is to coat all your scraps lightly with the material. Again, you should be adding one of these light layers for every 1 or 2” of scraps that have been deposited.
STEP #4 - Press Out The Air
Since this is a mostly-anaerobic process, we want to eliminate as much oxygen as we can. One helpful strategy is gently pressing down on your scraps (could be done before or after the bran mix is added) with something like a potato masher or small plate.
STEP #5 - Close the Lid
Yeah, maybe this is obvious - but we just wanted to make sure you don’t forget! Remember, we want as little airflow (i.e. oxygen) in this system as possible.
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STEP #6 (Once Up an Running) - Empty the Reservoir
Over time, leachate will start to accumulate down in the bucket reservoir. Every time (or every other time) you add new food deposits it’s not a bad idea to open the spigot and collect this liquid. Bokashi leachate has a variety of potential uses. It can be poured straight down the sink or into toilets, where it can reduce mineral build up and odours. Diluted, it can be used as a form of liquid soil amendment. We recommend 100:1 dilution for potted plants and as a foliar spray. Lower dilutions are well suited for outdoor gardens and composting systems.
HELPFUL TIP - Aim to let your scraps accumulate for a little while (maybe 2 or 3 days, depending on your waste stream) before adding them to the bucket. This way you are reducing the number of times the bucket is being opened, thus reducing the amount of oxygen getting in. Just remember, you should have a light layer of the bran for every 1 to 2” of scraps you add.
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Looking Ahead
Keep adding your deposits of kitchen scraps until your bucket is completely full, remembering to periodically drain off the leachate.
At this point, you should leave the system to sit for 2 to 3 weeks before moving on to “Phase II” of the process.
IMPORTANT NOTE: If you are not “ready” for Phase II, the good news is that a sealed bokashi bucket can be left to sit for many months - even years. Just keep in mind that the longer you wait to empty the bucket, the longer you’ll have to wait before using that bucket again!
Phase II - Aerobic Stabilization of Bokashi “Pre-Compost”
As touched on earlier, the key thing to remember (and be prepared for) relating to bokashi is that the end product - “pre-compost” - will need to go through an aerobic decomposition process in order to be garden-ready. Apart from being very anaerobic, this material can be highly acidic when it comes out of the bucket, so this extra breakdown period can be important for converting acids and other harmful metabolites into more plant (and animal) friendly compounds.
This is the stage where our actual composting methods can really come in handy - and in fact, we feel the best use of bokashi is as a partner strategy for more typical composting (but there are simpler options if you don’t want to go this route).
First, we recommend mixing the wet bucket contents with a bulky - ideally absorbent - carbon-rich bedding, such as shredded cardboard, hemp tow, or coco coir. Mixing in some form of living material (LM) as well would be even better, since this will help to inoculate the mix with beneficial, aerobic decomposer microbes.
During the winter months - when we won’t likely have good access to outdoor composting systems or soil - a mix like this could be left to sit in a plastic tub (with some air holes drilled into it) for an extended period of time. Just make sure you’ve mixed in enough bedding (and LMs) so that there isn’t any liquid pooling in the bottom of the bin.
During warmer times of year this bedding + bokashi (and hopefully LMs) mix could be dug right into your soil or added to a larger composting system. If you are putting it directly into a garden, just make sure to do so at least a few weeks before planting. If you plan to add it to a smaller vermicomposting system, you should let it age for at least 2 or 3 weeks prior to using as a food material - and even then, you should add it sparingly to make sure it is worm-ready.
Compost Tumblers - The Ultimate Bokashi Pre-Composter?
We’ll be the first to admit that we’re not huge fans of compost tumblers as actual composting systems. They tend to be far too small, the contents can end up getting too hot and wet, and they offer no protection against the elements.
Still, there is ONE job we feel they can be fantastic for: “pre-composting” your waste materials prior to adding them to one of your composting systems. They are especially helpful when you want to optimize waste materials for a vermicomposting system, and, as the title of this section suggests, also offer us an easy, effective way to stabilize our bokashi bucket materials!
Start by partially filling your tumbler with dry, absorbent bedding materials and living materials (if you have them), such as finished composts or really old leaf litter. Next, dump in the contents of your bucket, close up the tumbler, and take it for a spin! 🙂
Similar to aging this mix in a plastic tub, you will want everything to reach the point of no longer dripping liquid. It should be evenly damp - not wet - well mixed, and nice and bulky (this helps oxygen get where it’s needed).
If you let this mix sit in the tumbler - occasionally spinning it to introduce more oxygen - for a week or two, you should end up with something that would be great to add to a backyard composter or (even better) a vermicomposting system! Again, you should also be able to dig this material into your garden, if that’s your preference.
Summing Up
- Bokashi offers us a convenient, relatively simple way to deal with biodegradable kitchen wastes. It’s like composting in that it converts wastes into something more valuable, but it is actually an anaerobic fermentation process.
- One of the key perks of the process is that we are able to add a wider range of kitchen wastes, such as meat, dairy, seafood wastes and bones - but just remember that it’s not well suited for many bulky, outdoor wastes, and high-carbon “browns”.
- Add your scraps in layers of 1 to 2” - with a thin layer of the EM bran mix over top of each scrap layer - until the bucket is completely full (this happens over time, unless you have a lot of wastes initially).
- Periodically empty the leachate from your reservoir, and either pour it down your sink or into your toilet as-is, or dilute it and use it as a liquid fertilizer, or to add moisture (and microbes) to your compost bins.
- You should let the full bucket sit and ferment for at least 2-3 weeks before proceeding to “Phase II”, but a sealed bokashi bucket can be left to sit for much longer, if necessary.
- Phase II involves aerobic stabilization of your bokashi bucket contents. You should mix the bucket contents with enough absorbent bedding (and hopefully living materials) to soak up the excess liquid and bulk up the structure - and then leave the mix to sit for at least 2 or 3 weeks before digging it into your gardens or adding it to a composting system.
- Compost tumblers offer us a very handy way of converting bokashi “pre-compost” into a material that can be added to your composting systems or directly into your soil.
Helpful Related Resources
What Is “Living Material”?
Outdoor Vermicomposting 101
Layered Composting - A Simple Backyard Method to Build Nutrient and Microbe Rich Compost!
Recommended Products
Bokashi Starter Kit - Single Bin
Premium Bokashi Starter Kit
Bokashi Bran
1+ Year Supply of Bulk Bran
Effective Microorganisms - EM