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 this article and criticism Is based on false premises, and I would like to challenge a few of your statements in this article and comments. 1) “… and either dig it into your garden, or add it to your compost pile”. The third alternative which you don’t mention is the soil factory, the box of normal soil which allows you to compost your fermented kitchen scraps in your apartment livingroom in three weeks.
You go on to state that proponents of this method communicate that the composting goes on in the fermentation bucket. I have never read any material that keeps it a secret that the method is a two-step process where you first ferment, then compost in soil. Can you provide a link to a legitimate source of bokashi information that fails to mention the soil factory step?
?? Most discussions about Bokashi do not mention the soil factory.
https://www.gardenmyths.com/soil-factory-using-bokashi-ferment/
I use a 5 gallon bucket with a lid to collect my compostable kitchen waste. At first, the odors eminating from the bucket would get unpleasantly strong. I started layering with high carbon materials, like shredded cardboard, and noticed an immediate improvement — but still some odors lingered. On a whim, I started adding a splash of acid whey from my Greek yogurt production onto the paper layers as I added them to the bucket. This virtually eliminated the odor problem. Still some earthy smells, but little if any nastiness evident in the kitchen. It doesn’t smell wonderful when I finally dump the bucket onto the compost pile, but sure seems to break down fast after the addition. My hunch is that the acid whey is carrying enough lactobacillus to inoculate the bucket and outcompete the odor causing bacteria, although I haven’t found peer reviewed scientific research to confirm this. This works for me, and I’ll continue using it because it is virtually effort and cost free. At worst I’m adding the NPK of the whey to my compost.. I am also considering, as an experiment, feeding my worm bin with a portion of this pre-digested waste. What’s happening appears to be similar to the bokashi process, but again, no high-test inductive reasoning for “proof.” I’m sure glad that we humans were able to figure out things like beer, bread, cheese and yogurt (Gothic cathedrals, etc.) long before peer reviewed scientific literature was available to confirm them. I have difficulty imagining where humans would be today if we had always waited for pre-existing justification before trying anything new. There’s likely a kernel of truth contained in every myth. Perhaps we shouldn’t automatically exclude these possibilities in our search for useful information. Thanks for reading.
Bokashi is effective for the residential gardener who wants to decompose fats and meats and doesn’t have the required organic material to create a hot compost pile.
Aerobic composting releases carbon dioxide into the air; that carbon is lost. You are also losing nitrogen/ammonia whether it be a lot or a little.
By fermenting/pickling food waste first before putting it into the ground or into a worm bin all that carbon and nitrogen go directly into the soil food web and are not lost.
“all that carbon and nitrogen go directly into the soil food web and are not lost.” – if that were true, that would be a clear benefit. I found no evidence to support or contradict this idea.
It is quite possible that once in the ground it goes through a similar decomposition as in a compost pile and also releases CO2. The nitrogen would at least be lost to the soil.
In relation to the potential advantage that bokashi fermentation may reduce the carbon emissions that occur during composting…a study I have seen referenced (in Adam Footer’s book on Bokashi) is this: Dr Lawrence Green “A Pilot Study Comparing Gaseous Emissions Associated with Organic Waste Treated with and without Bokashi Fermentation” [case study], 2009.
However, personally I have been unable to find a copy of the actual text to read this study so I have no idea what it actually says…if anyone finds a link to it that be very useful!
I have contacted Dr. Green who started a company called Bokashi Cycle, for a copy of the study. I’ll bet it is a study that was never published.
I think whether bokashi is useful as a means of composting depends on circumstances. If you have a large garden and don’t mind that a mouse will come to nibble on some cheese then throwing everything on the compost heap is no problem.
It becomes more problematic when you live in close proximity to other people. In that case, you can pickle your meat, cheeses, oils and other “difficult” scraps to ward off pests before feeding the bokashi to the worm bin under your kitchen sink for further composting (NB: be careful of initially introducing bokashi to your worms, they might need 1 or 2 generations to get used to its acidity). The bokashi juice is acidic, so it’s much better put to use for eco-friendly toilet cleaning and drainage unclogging rather than for your plants.
All this great scientific discussion…thanknyou all… but do we explain to grow 17 corn plants, each of them gave fruits in just one planter planted directly over bokashi compost? Personally I believe what I experience… more to come this season about experimenting with bokashi in planters🌱 Have a wonderful year! A better one!🍷
Thank you for this insightful article! I use Bokashi because I live in an RV Motorhome full-time. Most parks do not have compost, including the one where I own my site. This is my home base. When traveling with Bokashi compost, I can store my food scraps until I can bury them. Because I am so close to my neighbors, the Bokashi offers me a less smelly compost option that doesn’t offend them. Thanks to your article, now I don’t feel so bad about tossing the “tea”. I mostly just use it in my RV tanks, ha ha.
I’m not competent enough to know if it’s a high quality study, but this seems to show the EM microbes having no measurable effect on yield or soil quality:
https://www.sciencedirect.com/science/article/abs/pii/S0929139310001332?via%3Dihub
The conclusion is quite clear “We conclude from our results that ‘Effective microorganisms’ did not improve yields and soil quality during 4 years of application in this field experiment under the temperate climatic conditions of Central Europe.”
EM had no effect. Which is not surprising – adding microbes to soil is unlikely to change the soil. In some specific cases, it can have an effect on specific diseases – maybe?
Thanks for posting the link.
A quiet recent study made by SLU in Sweden tested the amount of carbon that are released from a hot compost in comparison to bokashi, from start to finish.
The bokashi was better but it was really just slightly and it released a higher degree of other gases like methane.
So it’s probably something that should have more studies made to controll. Is it really a good practice?
It definetly is, by LCA it was determined that because Bokashi is not composting but fermenting, it has less green house gas emissions that compost and it does not emit heat. In my opinion both systems are great and should be practiced, if the heat and emissions from a composting method can also be utilized, this would fit perfect to close the loop through circular economy. The Bokashi tea used for hydroponics is also a way to close the loop, so as you can imagine there are infinite combinations of practices that can take us through a healthy transition towards sustainable living. It depends in each person and the level of commitment as well as liquidity.
Dear Robert, I agree with the kitchen scraps method in an air tight container. I am no scientist like yourself. Gardening is my profession, hobby, and true love since I was a child. I have 23 years experience professionally and 35 through passion. Your comment on different microbes acting aerobically and anaerobically (some both) is spot on in my opinion. The Bokashi method I have been using uses no kitchen scraps what so ever. I purely use oats, FPJ, and the EM-1 inoculant. I’ve done many trials and have shown good results to those without. I imagine in a garden your size an additional cost needs to be thought about when traditional or biomass compost additives work well enough alone. With my mix a white fungal material forms across the soil and throughout. These plants tend to thrive more in stressful environmental conditions. Certainly I am not debating your article. If I’ve learned anything experience and trial and error are the keys to success in gardening. My question is have you tried a similar method to what I do? Thank you for your time.
I have not tried it.
My big question is about used tissues. With allergies, my family’s number one trash item is used tissues. Does the bokashi system actually render the germs in these tissues harmless so I could add them to my compost?