Bokashi composting, also spelled bocashi composting, is a new way to deal with kitchen scraps. The proponents of the system claim that it has a number of benefits not found in more traditional composting methods. In this blog post, I will have a close look at Bokashi composting and separate myth from reality.
Bokashi Composting—What is it?
From Bokashicomposting.com we have the following description: “Bokashi composting is a safe, convenient, and quick way to compost food waste in your kitchen, garage, or apartment.”
To get started, you need a special bokashi bucket that has a tight lid and a spigot at the bottom to drain off liquids (pictured above). These will run you $60 to $150, or you can make a DIY for $20. You also need the ‘special sauce’! It would not be a very good process if there was no special sauce to sell you. It is normally referred to as bokashi bran or Effective Microbes.
The process is fairly simple. Put your food scraps in the pail and sprinkle some bokashi bran on top. Squish it down tight to get the air out. Close the lid. Each time you have more scraps, add them to the pail, add bran, and squish.
After a few days, liquid starts to form in the bottom of the pail. This needs to be drained, or it will start to stink. This liquid, the ‘bokashi tea,’ can be used to fertilize your house plants or your garden plants.
After a few weeks, when the pail is full, you take the contents outside and either dig it into your garden or add it to your compost pile.
That is the basic process. If you want more details or have specific questions about the process, there is lots of info on the net.
Benefits of Bokashi Composting
I found the following benefits listed at various sites on the net.
1) You can compost dairy products and meat.
2) No strong odors
3) No nutrients lost
4) No insects or rodents
5) No turning necessary
6) No need to worry about the amount of greens and browns
7) Food scraps are inoculated with EM (Effective Microbes)
8) Produces a nutrient-rich tea for plants
9) Can be carried out on a small scale, which is perfect for apartments
10) Very quick—complete in 2 weeks
11) Saying the word ‘bokashi’ will impress friends. 🙂
This sounds like a good system, and any system that returns kitchen scraps to the soil is a good thing. So in general, I have no problem with bokashi composting. If it gets you composting—great.
But… there is always a but. Is this really a method of composting? Is this system better than the more traditional methods of composting? These are the important questions and the ones I will look at in the rest of this post.
Bokashi Composting—Is it Really Composting?
If you read the above quickly, you might have missed the statement that says, “After a few weeks, when the pail is full, you take the contents outside and either dig it into your garden or add it to your compost pile.” Does this make sense? Why would you add fully composted material back to the compost pile?
If you read the fine print, you soon understand that bokashi composting is not a composting process at all. Bokashi in Japanese means to ferment. This process is actually a fermentation process. What you are doing is turning your kitchen scraps into pickled kitchen scraps. At the end of the process, the food looks just like it did when it went into the system, except it’s pickled. An orange looks like an orange, and an apple looks like an apple.
There is no composting taking place in bokashi composting—talk about false advertising!
Knowing this fact makes the earlier statement make more sense. Once you have fermented your scraps, you then need to compost them. You can do this by adding them to a compost pile, or you can just dig them into your garden soil, where they will compost naturally.
This system is especially promoted for apartment owners—what do they do with it after fermentation? Throw it in the garbage? They could have done that before fermenting.
Now that you understand the process, it is also clear why it is so fast—only 2 weeks. It is fast because there is no composting, which is a slow process.
Bokashi composting is not composting!
Bokashi vs Traditional Composting
The benefits listed above as #2 to #6, inclusive, are really not benefits when we compare the two methods. I make compost in bins and don’t worry about greens and browns—I just add whatever I have. It is outside, so the smell does not bother me, and if a mouse comes by for a bite to eat, so what! Nutrients can be lost if it rains too much, but they are lost to the soil below the compost pile—they are not really lost since the tree roots under the compost pile use the nutrients. If I really care about nutrient loss, I can cover the compost pile to keep out the rain.
Traditional composting, if higher temperatures are reached, can even compost meat and cheese.
The difference in the two systems is the pickling process. The apparent benefits of pickling are the Effective Microbes added to soil and the bokashi tea.
For more information on traditional composting, see Compost—What is Compost? and Benefits of Composting.
For a detailed comparison of Bokashi and traditional composting see, Bokashi vs. Composting.
Effective Microbes
Dr. Higa, the person who originally developed the bokashi system, also developed a special sauce that he called ‘Effective Microbes’ (EM). All kinds of special properties have been assigned to this mixture, but nowadays lots of people sell the microbes already added to the bran. Everyone in the industry now has their own ‘secret sauce,’ i.e., Effective Microbes + bran.
Adding the microbes is important since they control the fermentation process. For example, in winemaking, special starter yeast mixtures may be added to start the process. The reason for doing this is that you want the right kind of microbes to grow quickly and outcompete the ones that will create a lot of bad odors.
There are also claims that the EM are good for the garden. There are some studies that show a benefit from the microbes, but most show no positive results.
Testing of EM tea on field-grown crops found that they did not increase yield. Similar field studies have shown the same results. Effective microbes are important to make the bokashi system work, but they don’t really add any benefit to your garden.
Note (added April 2021): More recent research indicates that even the EM microbes may not be required for making Bokashi.
Nutritious Bokashi Tea
As fermentation progresses, excess liquid drains into the bottom of the pail, and you need to remove it. It is claimed that this tea is a great source of nutrients for your plants.
How nutritious is it? Some sites say that you can use it straight or dilute it 1:100. That is a huge red flag. A fertilizer that can be effective at full strength and at a 100 dilution rate does not make sense. Some people have commented that “it’s a biology thing, not a chemistry thing, and so the dilution does not matter.” They are saying ignore the nutrients because it is the microbes that are important. I addressed that in the discussion above. The science does not support the idea that the microbes add value. Even if they did, dilution by a factor of 100 would still be important.
There is very little published about the nutrient levels in Bokashi tea, which is odd since so many websites promote it. I did find one study and analyzed it in another post called Is Bokashi Tea a Good Fertilizer?
In short, it contains very little nitrogen, high levels of P and K, and several of the micronutrients are on the low side. It also contains high levels of sodium and chloride, both of which are toxic to plants at low levels.
Bokashi tea should not be used on container plants, and even in the garden it should be diluted 1:100 before it is used to reduce any potential damage from sodium and chloride.
Real Benefits of Bokashi
I am still not sold on Bokashi. The tea has no real value, and the fermented food scraps still need to be disposed of. If you are going to dispose of them in the garden, you might as well compost instead.
In recent years a new way of handling the Bokashi ferment, called Soil Factory, has become popular. I have discussed it in detail in Soil Factory Using Bokashi Ferment. It is a way to process the scraps in the home in a few weeks. You can even use my improved Instant Soil Factory method and eliminate the two-week period. Using these methods, Bokashi makes sense for apartment owners and others with no garden.
Both bokashi composting and traditional composting provide your garden and plants with the same benefits. Bokashi just seems to be an additional extra step that is not necessary. I would not use it.
That leaves us with one benefit from the list presented above, and this one can’t be denied. Saying the word ‘bokashi’ is cool and will impress your friends.
I think we’re into a discussion of semantics. What I call soil is the substrate I grow my food in. I wouldn’t say we have any clay, but sand and silt, yes. And our supply of substrate, that I am happy to call soil, has more than doubled over the years as we have added fermented organic matter to our initial soil (bagged, from the south) and sand (local).
Soil has a proper scientific definition. To have any meaningful discussion we need to use it.
Could you provide the source for your definition of soil?
Soil is not defined in this post.
Bokashi composting solved a big problem for us. We are on an acreage, where we have raccoons, rats, possums, loose dogs, coyotes, etc. And we have two dogs of our own. We cannot have food scraps lying around in an open compost bin or buried where the odor can be detected by such very sensitive noses. We also need a way to compost meat, dairy, and bones. We do not put food down our garbage disposal, because we’re on a septic system. Given those factors, Bokashi bins, combined with sealed tumbler composters, have given us a way to compost EVERYTHING, from food scraps to outdoor waste, in a way that does not attract critters. (In fact, I read that adding Bokashi waste to a regular compost bin or pile actually deters some critters because they do not care for the fermented material.) We add the Bokashi to our sealed tumblers. We have mostly clay, which needs a lot of amendment for any plant that needs well-drained soil. This multi-step composting process gives us a way to add fully broken-down organic material to our planting beds, and it is all produced from waste that would normally go to the city dump. As far as your claim that the Bokashi fermenting step is not composting, no one ever said it was, and, frankly, I think you’re being unfair–even petulant– in your comment that there’s false advertising going on. Everything I read about Bokashi composting explained that it is a multi-step process involving, first, fermentation in the bucket, then composting via burying or adding to a regular compost collection. It is a process for using waste that could not normally be composted through other means, and it works perfectly for that. I cannot comment on the tea that Bokashi makes. That was not the primary purpose of the Bokashi system for me. I did read the article that you cited, and the authors made it clear that a lot more studies are needed to prove or disprove the effectiveness of any type of tea on crops, yet you seem to consider yourself qualified to bash Bokashi tea’s nutrient value simply based on your own non-scientific analysis and with no personal experience with it. It is too bad that people will read your post and dismiss Bokashi as a fraud when it has so many benefits for so many people in circumstances different from yours. Your article could/should have been much better considered and more objectively presented.
re: “As far as your claim that the Bokashi fermenting step is not composting, no one ever said it was,” – that is not true. Even you called it, and I quote, “Bokashi composting”.
Porsche has en electric car called the Taycan Turbo. Does it use exhaust gasses to power a turbine to pump more air into the combustion chamber? No, of course not. It it marketing wank.
Anyway, when I got my kit, (not the car) all the documentation spoke about pre-composting and made clear that it is NOT actual composting.
We started adding Bokashi because our soil was quite poor because this is a new house and the soil was basically sand.
Now stuff still grows there. It does attract worms and makes the soil look much better after quite some time and of course we can put in a lot more stuff then one could so on a compost heap.
I know it is not a miracle method and the tea does not do anything, but just being able to convert all kitchen scraps, not having to worry what can and can’t go in is quite convenient. And if it actually helps enrich our dessert garden a bit, then fine. Good enough for anybody I’d say.
We find Bokashi processing useful for the same reason you stated. It allows us to pre-treat meat, fat, and dairy so that it can then be added to our compost without attracting animals. This is a huge benefit, because these animal components in compost are very rich and diverse nutrient sources … obviously so based on the relative explosive plant growth and vitality compared to purely plant based compost.
I do think there’a lot of hype surrounding Bokashi though, and the EM is complete unnecessary. Years ago I studied microbiology and worked as a micro tech in clinical labs. For years now I’ve made beer, wine, and various lacto-ferments such as sauerkraut. The microorganisms , primarily lactobacilli that ferment vegetables to make lactose-ferments are the only necessary for Bokashi. They’re salt tolerant, and so adding a little table salt and leftover homemade sauerkraut is all that’s necessary. Any other organisms in the EM probably won’t survive.
So imo Bokashi processing is no substitute for composting, but it is an easy way to add very rich animal nutrients to compost without drawing rats and other scavengers.
My experience with bokashi is that it is good for pickling composting materials that would otherwise attract animals and it is incredibly helpful in growing sweet potatoes.
When I used EM1 on my garden it did generally nothing to the crops that grew above the soil. However, I have found it incredibly helpful in increasing health and yields of sweet potatoes and possibly for increasing yields of carrots or at least increasing the health of carrot plants. My experience with sweet potato yields is not just from observation. One year I planted several kinds of sweet potato and put yam one on a few plants and not on the others. There was a dramatic difference in both the size of the leaves and Vines as well as the potatoes. Another year, when I had some kind of blight destroy the rest of my vegetable garden, I was able to save my sweet potato plants by spraying them with diluted EM1. The blight subsided on the damaged sweet potatoes and all the new growth was healthy. I do not know why EM1 works with sweet potatoes, but my experiences in Arizona and northern California have led me to believe that it does. I usually do not just take people’s word for what works in the garden. Most of the time I try things out to see if each claim is actually true.
One interesting topic I would like to find out is if black soldier flies have the same type of fermentation bacteria in their guts as what is found in EM1. I currently have a very large black soldier fly colony tha I keep from year to year and I believe the way they are able to digest so many different things from utilizing some combination of fermentation bacteria.
I use Bokashi as a soil amendment, along with biochar and traditional compost. We have very alkaline, non wetting sands over limestone as our ‘raw’ soil and it is not very veggie friendly. I find the Bokashi a convient method of dealing with kitchen scraps and adds a huge amount of organic material to the beds that breaks down into organic material quicker than just burying the scraps.
Conventional year round composting in our area is twice as hard, as our rainfall is very low and our temps very high (looking at 46 celsius this week), and watering the compost is a waste of valuable water.
We are trying very hard to replicate the processes used to produce Tera Preta soils for growing our veggies etc.
I appreciate the critical thinking in this article. After reading your blog post I continued my search for analysis of bokashi, specifically the liquid, and came across this. Thought you would be interested in it. https://repository.wellesley.edu/cgi/viewcontent.cgi?article=1753&context=thesiscollection
It is an interesting article.
1) It deals more with an agricultural form of bokashi – something I have not discussed on my blog. In many countries a form of large scale bokashi is used with manure being a main input – but the input depends very much on the material at hand. As such, I am not sure if any of the conclusion apply to what home gardeners are doing?
2) This paper has a major flaw which I see a lot in compost/manure type papers, especially for compost tea. They applied bokashi to plants and their control was doing nothing. Bokashi produced better growth. This does not really prove very much because we know that adding excess nutrients to soil will produce plant growth.
They should be comparing manure to bokashi made from the same manure. That would show if bokashi adds anything to the process.
3) The growth testing was done in posts, so we don’t know if any of this can be transplanted to soil.
I have been Bokashi composting for over four years, I have not seen any noticable benefits to date. I am now trying one spot and burying the Bokashi in the same spot and giving that spot four weeks to break down the Bokashi fermentation before adding another bucket. I am on my third round in this spot, I have noticed the soil getting darker in color and no visible signs of the Bokashi waste and an increase in worm population in this spot.
In the spring of 2019 I will plant a rose bush in this spot and see what happens, this spot has not produced a rose bush in over ten years.
Robert,
This is the first year I have grown anything, (Lot to learn)
Never done any type of composting but want to start.
I think you are not looking at this correctly.
Let us only look at meat and bones.
In a compost pile or put directly on the ground you will have the following problems.
1) Smell
2) Rats dogs etc so you will lose it anyway.
3) Disease
Bokashi stops the smell and the disease as soon as it is put in the bin,
If you bury the contents in the soil you stop rats etc.
So it is not about which works faster rather the fact that you can safely add meat bones etc.
It is true that you can get rid of meat this way. It is the bokashi proponents that claim the process works faster – not me.
While I do appreciate a critical stance (I have seen the most ludicrous claims made on behalf of bokashi), I think you miss the point with the benefit for people living in flats without access to a garden. Bokashi allows me to make soil indoors, from start to finish, without foul odours. I first make the bokashi, then use leftover soil (from plants etc) and blend in big bags that I have around the house. So instead of having to throw away food scraps (I have no garden to keep a regular compost in, and my apartment block/town doesn’t collect organic matter but instead burn it for energy. And I anyway want the compost for my own use.)
I did say “The system does give you a way to keep food scraps in the house.” Agreed that for people in apartments it has some benefits.
I disagree with “Bokashi allows me to make soil indoors”. Bokashi does not make soil. You are adding the ferment to soil, and thereby adding nutrients to soil, but you do not produce soil.
I will be posting some more on this topic soon. If you take the kitchen scraps, and put them in a blender, then add the liquid to soil, you will have the same effect and you can skip the fermenting part.
I have been following this thread for quite a while now and I’d like to add my perspective.
Bokashi is not compost. It is a fermented organic matter that is free of pathogens and coliforms due to the acidic anaerobic process that out competes the bad bacteria. Once the Bokashi is ready to breakdown, it can be mixed with garden soil or added to a container with garden soil. The fermented organic matter will break down in under a month outdoors and two months indoors.
That result is a soil that is richer in organic matter, beneficial bacteria, fungi, moisture, gases and minerals. All of which are the main components of soil, by the way. Yes Bokashi turns into soil. The Bokashi attracts worms, nematodes, archaea and other organisms, which create a strong ‘soil food web’ that is crucial for vegetation. Bokashi will increase the microbial, mineral and nutrient density of the soil food web, thereby increasing the brix° of the plant. This is a fact that is proven by testing with a refractometer. We have conducted numerous tests and the findings are conclusive. Saying that we had our Bokashi culture mix analysed and it came back with an NPK of 2.74:1.46:1.27 with other micronutrients and trace minerals. There are obvious benefits to using Bokashi, thereby avoiding synthetic nutrients.
Re: That result is a soil that is richer in organic matter, beneficial bacteria, fungi, moisture, gases and minerals. All of which are the main components of soil” – actually that is exactly true. Living organisms are not part of soil – they live in soil.
Re: “The fermented organic matter will break down in under a month outdoors and two months indoors.” Not sure how you define breakdown, but if you mean decomposed, then provide some evidence of this?
I never said that Bokashi does not add nutrients to soil.
Increasing Brix is not really of much value to food crops. Show me evidence that it is of value to plants.
Robert, you make a point about living organisms not being part of soil.
As I understand the science, plant roots can only take up nutrients that have been mineralised in the “soil solution” – the water film around them. These nutrients can only get into a mineralised form in two ways: artificially in man-made chemical fertilisers; naturally transformed from non-mineralised form by living organisms, mainly bacteria, archaea and fungi, some of which operate in the gut of larger organisms like worms.
Therefore if you exclude living organisms from it, “soil” is not a practical concept. Plants cannot grow in such a soil without artificial help. Your definition of soil may be physically satisfying to you, but it is not biologically satisfying to organic gardeners.
It is not my definition of soil. It is the definition accepted by soil scientists. I am just the reporter of facts.
In Iqaluit, I can buy a small volume/weight of soil in a bag for $40. Too expensive, and the stuff in the bags is of poor quality. The “soil ” available on the land is mostly sand. More on that another time. I do consider that I am making soil by adding my fermented waste to my indoor bins (that contain soil dug up from beds from previous summer) as I am continually increasing the amount of soil matter available for planting. In the fall every year, I put soil from my small greenhouse and cold frames into bins for my winter composting.
Incidentally, comparing north and south this year, my northern greens were “head and shoulders” far superior to my southern (bug eaten) ones.
If you are creating soil, where is Bokashi getting the sand, silt and clay?
Hi. Every fall, before the soil in our greenhouse and cold frames freezes, we remove soil from the beds into Rubbermaid bins which we bring into the house when we have 5-gallon batches of fermented waste that need to be buried. We bury the fermented waste in this soil, reconditioning it with the waste, for the next season. This stuff stays in the house all winter… So, yes, initially, years ago, we obtained local soil (mostly sand) and some bagged soil imported from the south. Since then the amount of soil that we have keeps growing – the only input into our system over the years has been seaweed and kitchen waste. Now we have more “soil” than we know what to do with – stored in Rubbermaid bins outside the greenhouse… So, I would say we are “growing soil”…
You Are building up the organic component, but the sand, silt and clay have not changed.
Well, clearly something happens. If you put scraps in the blender the breakdown is mechanical. Since very little is left of the visible food scraps in the bokashi soil, something must have happend to change its form. I won’t say what it is and if you can shed light on that, fine. But to say that nothing happens is just untrue.
On a molecular level, not much happens by blending. Our eyes only see on a macro level, not on a sub-micro level.
Don’t bury bokashi with a dog around. He’ll dig it up. Not sure on what it will do to a dog’s digestive system! Anyhow, I empty bokashi bin into compost tumbler It breaks down within days and seems to assist in the breakdown of other materials in compost bin. Anecdotal evidence only.
I’m a big fan of bokashi, with a soil factory (I seldom add the bokashi directly to my garden) and with bokashi you are in fact creating soil, just as you do with compost.
If you compress bokashi in a 5 gallon bucket, even when you drain it you are left with 30-40 lbs. of material. That didn’t disappear during fermentation, and it won’t disappear once buried. It bulks up your existing soil.
Perhaps you could add bokashi to one large rubbermaid bin of potting soil/coir, and set up another bin as a control? What you’ll find is that mass is not created nor destroyed.
Also, your bokashi bin is basically full of the pulp (and bone) that would ruin your blender, and most of what you extract as a liquid would be drained off.
1) “with bokashi you are in fact creating soil” – not including the air and water, soil is 95% sand, silt and clay. Bokashi does not produce these so it does not produce soil.
2) Fermentation is not a decomposition process – so yes after bokashi you still have about the same bulk as before. However, once in soil it decomposes and much of its bulk is lost in that process.
What happens if I add liquid food waste to bokashi bin?
Most of the liquid would drain out of the bottom of the pail.
I think some liquid is ok but you don’t want to end up with a sloshing bucket. I don’t bother with spigots on my buckets and so there is no draining until it’s time to bury the buckets’ contents. Incidentally, I have experimented (beyond my arctic home) with burying buckets of waste in my front and back yards (postage stamp size, in a town house row in Kanata suburbia). The buried waste did not attract any animal visitors.
I have been using bokashi buckets for nearly a year now and I find them to be excellent. I have two buckets to allow extra fermentation time of the first bucket while I fill the second. Once the second is full I dig a trench in the garden, dump the fermented food scraps from the first bucket (which yes still look similar to how they looked when I put them in the bucket) and cover with soil. The huge benefit that you have missed in your article is that the fermented food scraps break down super fast once they are in the ground, and are completely composted (and look just like soil) within 1-2 months. The bokashi also attract loads of earth worms, the soil is inundated with them where the bokashi was put in the trench. This method is convenient, easy, and super efficient (much more so than my traditional compost bins). If you struggle with traditional composting I think you’ll be very impressed with the fast results that are standard with bokashi.
Can you provide proof of “The huge benefit that you have missed in your article is that the fermented food scraps break down super fast once they are in the ground, and are completely composted (and look just like soil) within 1-2 months.”?
Just because it no longer looks like the food does not mean it composted faster. This is a claim some people make, but no one has been able to provide any proof that it is true. As a simple test, I took raw food scrapes, and put them through the blender. I then mixed it with soil. Instantly, without any bokashi, I had what looked like composted material.