How to make a simple soil factory

Nutrient and microbe rich bokashi compost

What is a soil factory?

A soil factory is a place where you produce high quality nutrient rich soil. It’s your go-to place for compost and potting soils. It’s just like your bag of shop-bought compost but it’s home made and you know exactly what has gone into it!

How will a soil factory help in my garden?

A soil factory provides a great place to put your bokashi pre-compost throughout the year but can be especially useful during the winter and summer months. During the winter my ground is often too frozen and hard to dig a trench to bury my pre-compost. My soil factory provides a great place to put my pre-compost and serves as a great source of fantastic compost when spring comes around. During the summer months I like to use every possible space to grow fruits, veggies and flowers and it can be hard to find a spot to bury my pre-compost. So, once again, I turn to my soil factory for my bokashi pre-compost. I then simply go back to my soil factory whenever I need compost. Its really just like a small, portable, low-maintenance compost pile.

How to make a soil factory?

Making a soil factory is easy. There are a number of different methods for making a soil factory. Below are two of the methods we have found to be successful; using a container or burying in the ground.

Using a container

Step 3: Add a few inches of regular garden soil and mix slightly
Step 3: Add a few inches of regular garden soil and mix slightly

Step 1. Find container

Find yourself a large plastic box with a lid. Drill a few holes in the bottom to let liquids escape. If your soil factory will be positioned on impermeable ground (such as a patio, garage or balcony), then do not drill holes in the bottom.

Step 2: Add garden soil

Next, put 3-4 inches of regular garden soil at the bottom of the container. *Tip* Try to use healthy soil with lots of life in it. The more worms and grubs the better!

Step 3: Add your bokashi pre-compost

Then you are ready to add your bokashi pre-compost. Empty the contents of your fermented bokashi kitchen composter to the container, making sure to break up any large lumps of pre-compost. Add another couple of inches of regular garden soil and mix slightly with a garden shovel.

Step 4: Add more garden soil

Add a few more inches of regular garden soil and place the lid on the container. The final mix of soil : bokashi pre-compost : soil should be about a third, a third, a third. The depth of each will obviously depend on the size and dimensions of your soil factory.

Put a couple of stones on the lid to weigh it down, if needed.

Step 5: Wait

Leave for 2-4 weeks and check your soil factory. It may take slightly longer for your pre-compost to break down in your soil factory than when using the trench method as there are fewer worms and other soil biota in your soil factory. Colder temperatures may also slow down the process too. You can speed the process up by chopping and missing the contents of your soil factory every week or so. Be patient, the pre-compost will break down and you will have a soil factory full of great compost.

Step 6: Use compost or add more pre-compost

Feel free to add more pre-compost to the top of your soil factory. Remember to mix the contents each time after adding. Remove compost as needed. Remember, if you expect to need compost within 2-4 weeks, don’t add any fresh pre-compost to your soil factory. If you want a regular place to put your pre-compost and a place to constantly get compost then we would recommend setting up two soil factories.

Burying in the soil

Making a soil factory in the soil is really a combination of the above container soil factory and the regular trench method for burying your pre-compost.

Step 1: Choose an area 

Firstly, choose an area in your garden that you don’t need for planting in the coming months.

Step 2: Bury your pre-compost 

Next, use the trench method to bury your pre-compost. Rather than planting directly into this area, use this area for collecting compost to be used on the rest of your garden.

Step 3: Make a grid pattern

You can set up a grid pattern if you have the area is large enough. Add pre-compost in rotation to 3-4 areas in your soil factory area. This gives you a regular place to bury your pre-compost and a constant supply of compost. It also has the added benefit that you don’t need to plan your planting schedule around when your pre-compost will need to be buried.

You might also like to read

The importance of healthy soil

Bokashi composting: how to get started

8 thoughts on “How to make a simple soil factory

  1. Hi there!

    If the soil factory container was clear and left on a balcony, would that matter? Or does it need to be opaque?


    Hannah 🙂

    1. Hi Hannah,

      Interesting question! Keeping the soil factory on your balcony should be fine as long as you can keep it out of direct sunlight to prevent it overheating and killing the life inside the soil. Ideally the container should be opaque to create an environment favored by soil biota (ie dark). You could simply place the container in a large black garbage bag or wrap it in newspaper, old carpet etc.

      I hope that helps. Feel free to ask any other questions here 🙂

      Nicki and the Bokashi Living team

  2. Thank you so much for this! My soil factory had too many flies – the instructions said that it should be kept open with a sheet of paper to cover it. I’m guessing that your method with a container will not have a fly problem? If so I will try it. Please let me know about flies and insects as I live in an apartment and don’t get any direct sunlight. Thanks.

    1. You really shouldn’t have a fly or insect problem with a soil factory. I’ve never heard of anyone recommending to just cover it with a sheet of paper before! Definitely try the large container described in this blog piece. The pre-compost tends to take a little bit longer to break down in soil factories than when it is buried in the ground or in a compost pile. If possible, make sure you start with some good healthy soil (with lots of worms). We would love to hear how you get on 🙂

  3. Should the container for soil factory be air tight. I have balcony space , no ground space. Need to ensure no flies , pests etc .

    1. The container doesn’t need to be completely airtight; although a good fitting lid will help keep rain out and any bokashi odors in. As you are keeping your soil factory on your balcony, you won’t want to drill holes in the bottom to let liquids drain. We would therefore recommend adding extra garden soil to ensure that the soil factory doesn’t get too wet.
      Hope that helps. Please let us know if you have any other bokashi questions.

    1. Hi Daphne,

      It will work, but it will take longer for the pre-compost to break down. It is the life (bugs, worms, microbes, fungi etc) in the soil of the soil factory that breaks down the pre-compost. So the less life your soil in your soil factory has, the longer it will take to break down the bokashi pre-compost. Recycled potting soil is probably the best of your two options as there will be some biota in it.

      To help the pre-compost break down as quickly as possible we would recommend chopping your food waste into 1″ or smaller pieces, adding plenty of bokashi bran and leaving your kitchen composter for a little longer to finish the fermentation stage.

      Happy composting 🙂

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