I am seeing the term soil factory used more often, usually in discussions about Bokashi or Vermicomposting. I’ll restrict this blog to discussions about Bokashi, but most of the comments also apply to Vermicomposting.
It is claimed that Bokashi ferment, the material remaining after the fermentation process, can be used to make soil, which can then be used for house plants or in the garden. This would be quite a feat if true. It takes nature millions of years to make soil and now Bokashi enthusiasts can do it in a couple of weeks.

Soil Factory Using Bokashi
How does the soil factory work? The following description from the Bokashi Composting Guide is a good explanation of the process.
“Making Your Own Potting Soil: To create your own soil factory you will need a large open container or tub. First add a layer of used soil (20 litres), then dump in the contents of your Bokashi bucket and break apart the waste. Next add another 20 litres of soil and mix it into the fermented waste. Finally top off with another 20 litres of soil and ensure that all the contents are moist but not wet. After a few weeks you will have a good supply of an amazing nutrient rich potting soil.” (ref 1)
I wonder how much soil you produce? I’d guess it is just 60 liters, the amount of soil you started with. A pail of Bokashi ferment is mostly water. A small amount of organic matter would be added to the soil but would have almost no effect on the volume of soil.
Soil consists of dead organic matter, sand, silt and clay. A soil factory does not produce any sand, silt or clay so it does not produce soil. The term soil factory is very misleading.
Statements like “A soil factory is a place where you produce high quality nutrient rich soil”, are just plain wrong. It does not produce soil, and there is no evidence that the resulting product is ‘high quality’ or ‘nutrient rich’. The soil structure has not changed. The only thing that has happened is that it has a higher level of organic material, but this organic material has not started to decompose as explained in Bokashi vs Composting.
Benefits of a Soil Factory
The term Soil Factory may be a poor selection, but there are some real benefits to it. I first became aware of the procedure of adding Bokashi ferment to soil through social media; it seems to be a more common practice in Scandinavian countries. In a few weeks the fermented kitchen scraps plus soil are turned into something that looks like soil. You no longer see the pickled scraps.
I gave the method a try and sure enough the fermented material falls apart fairly quickly and seems to dissolve in the soil.
The benefit for the home owner is that they don’t need a garden to get rid of their Bokashi ferment. They can do it right in their home and the resulting soil can then be used for house plants or planting containers. This certainly makes Bokashi more appealing for people living in apartments.
What Does the Soil Factory Produce?
The stories I heard from Finland and Sweden claimed that the Bokashi ferment decomposed in a couple of weeks after being added to soil. I haven’t found a single study that looks at what happens to the ferment once it is added to soil. To our eyes it seems to disintegrate into the soil, but decomposition is a chemical process and we humans can’t see it happening.
We do know that decomposition is a slow process that happens in the presence of both bacteria and fungi. Knowing this, it is almost a certainty that the soil produced by the soil factory does not contain decomposed material. It might look like finished compost, but it’s not.
Traditional bin composting takes months, and even so-called finished compost still takes years to complete the decomposition process.
The result of the soil factory consists of the added soil plus un-decomposed organic matter. There is nothing wrong with that. The real value of organic matter is that it decomposes slowly over time – that is a good thing.
A New Type of Soil Factory
While experimenting with this process I decided to try an improved soil factory method. The current method requires that the soil and Bokashi ferment sit for a couple of weeks. My new method eliminates this two week waiting period, making it much faster.
The Instant Soil Factory
Take your Bokashi ferment and homogenize it in a blender to make a smoothy out of it. Then pour it into the soil. Mix it up and you are done. Instant fortified soil with no waiting period.
The ferment homogenizes very easily in the blender since the food scraps are already mushy and contain a lot of water.
You can also replace the soil with coir and produce a product free of insects and plant diseases. The coir is quite dry and easily absorbs all of the liquid in the ferment. The result is a fairly dry, soil-less mix that has no odor. The ferment will continue to decompose over time and help feed plants.
I call this new method the Instant Soil Factory.
References:
- Bokashi Composting Guide; http://www.greencalgary.org/index.php/download_file/view/493/343/
- What is Bin Composting?; https://www.gardenmyths.com/compost-what-is-compost/
Any idea of how long it would take to break down the bokashi results in a static aired pile? Of course soil micro would be added to pile after it drops acidity. Thanks!
OMG! I am more confused than ever. I compost in two tumbler bins outside. My outdoor bins never get very hot b/c I don’t have a big enough source of “green” at one time to fill a bin. Instead, I dump my food scraps every couple of days w/appropriate amount of browns. So the volume I’m composting is too small to create enough heat. I was hoping that by using the Bokashi method, i could collect a larger amount indoors and then use the fermented “stuff” as my green material. This way I have a larger quantity to add at once. I also hate having to run out every couple of days to empty my kitchen scraps.
So the question is, can I use the Bokashi bucket to collect larger amount indoors and then use the fermented stuff to use as my greens in my outdoor composting tumblers?
yes
Thank you for all of the wonderful information!! I use a blender on all of my kitchen scraps before I pore them in my composter (tumbler type) I was wondering if I add bokashi method into my system if I could continue to process the fresh scraps prior to placing them in the bokashi bucket?
Sort of – the idea is to do bokashi in the bokashi bucket.
I didn’t ready all comments, maybe what I am saying here is already pointed to above. I understand compost, bokashi, or any other form of changing scraps into soil is important not mainly because of how much nutrients it makes available to plants, but because how it makes easier for microorganisms and worms to digest the nutrients…. And what they digest is available for plants. And this brings us to benefits of compost and no dig garden. Doesn’t apply same way to container gardening which requires more intense soil enriching process
I think bokashi advocates are distinguishing between soil and dirt. Dirt contains the elements of sand, silt and clay. Soil is more complex. I’m digging learning more about this, especially from Dr. Elaine Ingram. https://www.youtube.com/watch?v=xzthQyMaQaQ
1) Dirt is the stuff you sweep up inside the home. Soil is made up of sand silt clay, water, air, and dead organic matter.
2) A lot of what Dr. Ingham says is not supported by science. Some of her early writing made sense, but a lot of her latest work does not.
I use bokashi for collecting and storaging the kitchen scraps before taking them to the compost pile at my summer place.
I live part-time in an apartment without separate compost bin. It takes about two to three months to fill up the bokashi bucket and it doesn’t smell at all. We are not allowed to put biowaste to garbage and I don’t see any point in buying an expensive compost bin just for some banana peels, coffee grounds and random vegetable leftovers.
So for me bokashi is just a convenient way to collect kitchen biowaste without the need to empty it every other day – and it doesn’t hurt to reuse the nutrients 🙂
If I layer plain kitchen scraps (not fermented) with a nice healthy soil that has lots of microbial activity going on in a big bin, will the kitchen scraps break down in a couple of weeks with minimal smell? Trying to figure out a bear safe way to compost my kitchen scraps and create potting soil.
Depends on how you define “break down”. Even in a compost pile they take years to fully break down.
Logically, JS received little encouragement from local government because their concern would be to reduce rodents rather than reduce food waste in a landfill. Wouldn’t food waste decompose quickly compared to all other garbage in the landfill?
There are two reasons to compost:
1. for growing plants
2. if you are trying to reduce the cost of your garbage collection which is calculated according to it’s weight or volume.
Thanks for lots of information. I can see that many people have completely Different needs wants and ideas but it’s great to be able to read them to help me make decisions.
Thanks again. Kev H.
Hi.
I have read other of your bokashi posts and I really have the feeling that it is not useful nor necessary.
Wouldn´t be the same if I only homogenize kitchen scraps in a blender and mix it up with the soil? I mean, I would have un-decompoosed organic material mixed with soil. What does the fermentation stage add to the final product?
Thanks
That is exactly what I tried. Made soil in about a minute. I don,t think I wrote about this but did mention it somwhere.
The problem is that I can,t find any reliable information that tells me what the bokashi process does on a chemical basis. So I don,t kniw if it adds any advantage.
Thanks again.
If I found any information, I will let you know 😉
See information on underlying biochemistry in the Wikipedia Bokashi page. Reliability of Wikipedia varies, but this is reasoned (compare with “Effective Microorganism” which is an EM magic puff). The biochemistry integrates other linked wiki pages such as Fermentation and Lactic acid – established science. The page moans about how focus on EM has diverted attention from more important elements like what happens in the soil.
I have been using the bokashi system for a while now.Last winter i filled 4 80liters containers only by mixing the bokashi buckets from what me and my husband consumed with the spent soil from pots that we emptied at the end of the season. First of all, the bokashi bucket was far from being 90% water, we hardly squeezed out a 100 ml once every 4-5 days… big question mark on that? But all in all, science aside, our tomato plants and other herbs growing together with them, went wild in the bokashi soil. I don’t mean to be mean, but have you been using bokashi before posting the above?
I am reporting on what science knows about Bokashi – not my personal experience.
I never said anything about 90% water – please read the actual post.
Food scraps are mostly plant based and all plants are mostly water, which accounts for Bokashi being mostly water.
A study of food waste across almost all counties of Wales found that food waste (and hence bokashi) is on average 75% moisture. Farmers are advised by CSIRO in Oz to let grass wilt after harvest to 70% before inoculating it with silage bacteria (same process as bokashi). Seems to be a pattern here.
The water content is important because it enables the lactic acid from fermentation to convert to lactate, a natural food that attracts soil bacteria and sets in motion the rapid consumption of bokashi by the entire soil ecosystem. Don’t add bokashi to bone dry soil.