How to Use a Bokashi Soil Generator to Turn Food Waste into Nutrient-Rich Soil

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What do you do with your bokashi bin contents if you don’t have a large garden to dig them into? As discussed in the previous Bokashi Composting article, you can always put the processed bokashi food waste into your compost bin or into your worm farm (a little at a time till the worms get used to it!), but what do you do if you don’t have either of these options? The good news is that you can covert your bokashi bin contents into dark, nutrient-rich soil in as little as a few weeks with a simple DIY device called a Bokashi Soil Generator! The fancy name actually makes it sound more complicated than it really is, the process is so simple it’s unbelievable, and the equipment used is readily available anywhere.

Keep in mind that you cant store the completed fermented bokashi contents for any serious length of time, but when you convert the material into a bokashi soil, you can store it and use it as a planting mix or soil amendment in pots or in your garden in the same way that you use compost – you can dig it into the hole when planting new plants, or dig it in to the soil around existing plants.

Building a Bokashi Soil Generator

To build a Bokashi Soil Generator you will need the following materials:

  • Any large container with drain holes or without a bottom to use as the soil generator – a 40-50cm wide plastic pot is ideal.
    (In terms of size, choose a container large enough to contain your bokashi contents and a similar volume of soil)
  • A lid or cover for your container (does not need to be airtight or a good fit)
  • Your completed bokashi container contents
  • Garden soil (or used potting medium/potting mix that you wish to recycle)
  • Compost (optional)

The construction steps are as easy as filling a pot with dirt!

  1. Select a container with drain holes or without a bottom to use as the soil generator – any recycled container will do.
    Sit the soil generator container over a garden bed or path so any liquids can drain into the soil.

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    Here I’m using an old 50cm wide plastic pot as the soil generator container, sitting on a garden oath.


  2. Next, you’ll need some compost, just dig some out of your compost bin or comport heap.The compost is optional and is used as an inoculant to add lots of beneficial microbes to the mix to speed up the conversion into soil.
    If you don’t have compost, just use soil or recycled potting mix.20141023_185240
  3. Pour the compost (or soil or recycled potting mix) into the container until it is approximately 1/3 full.20141023_18534320141023_185400
  4. Empty the processed bokashi food waste into the container.
    bokashi bin completed
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    Notice that the processed food waste still looks like regular food waste, only pickled!

  5. Mix the materials to blend them together if you want to produce bokashi soil in around 4 weeks
    OR if you prefer not to do any mixing and want to produce bokashi soil in around 12 weeks then leave it alone and proceed to next step.
  6. Pour garden soil (or recycled potting mix) over the top of the (mixed or unmixed) bokashi contents to cover them up. This will create a ‘sandwich’ of three layers with compost (or soil or recycled potting mix) at the bottom of the container, the bokashi contents in the middle, and soil (or recycled potting mix) on top.20141023_18573420141023_190005
  7. Cover the container with a lid or cover to stop it drying out in warm weather or getting flooded in wet weather. The lid or cover can be loose fitting, and does not need to be airtight. Even a piece of board will suffice.Now just let it sit there for four weeks if mixed, or twelve weeks if unmixed, and allow the microbes to do their work, that’s basically it!20150629_162256
    The second pot in the background is covered with a mesh tray so rain can enter, this will work when the weather is mildly warm with light rain.


    Completed, well maybe…

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    A quick check shows there are still some visible ingredients, leave for a bit longer…


  8. Truly complete. The end product is rich, dark bokashi soil, and the original materials are no longer visible.(The stuff visible on the surface is just debris that has blown into the pot when the cover was removed and tiny seedlings emerging from seeds blown in by the wind – so yes, it’s fertile enough to raise seeds in!)20150426_132653

Using a bokashi soil generator you can process bokashi fermented food waste to convert it into soil which is ready to use in your garden or container plants, making it ideal for people with small gardens.

Even for those with gardens who can’t be bothered digging (like me, I’m a no-dig gardener), this is a great way to produce rich organic matter to incorporate into your garden to improve your soil.

In case you’re wondering, a no-dig gardener will add fertilizer and any soil amendments such as bokashi soil, compost or worm castings to the top of garden beds at the start of spring and autumn, and then cover the lot with a generous layer of mulch, and that’s all the soil work for the next season’s gardening!

References:

Adam Footer – “Bokashi Composting; Scraps to Soil in Weeks”, New Society Publishers, 2014.

13 thoughts on “How to Use a Bokashi Soil Generator to Turn Food Waste into Nutrient-Rich Soil

  1. Fantastic article! I’d been wondering if something like this could work. My brother rents in a place with lots of space but no garden beds, and he’d been wondering about the different options for composting that doesnt require a permanent structure. I reckon this is might be a good solution!

  2. Thanks so much for this article. Here’s what I did with my waste. https://anitaelise.com/2017/09/15/kitchen-waste-composting-at-home/ The instructions said to layer cocopeat with the fermented pickle and it would be ready in 2 weeks. I found the older layer was composted, though a little wet, but the newer layer in the bin was not completely done. I think I’ll follow what you say and wait for 12 weeks until it is soil. Only, that is going to mean I need a lot more storage than I’d planned (I live in a flat/appartment and compost in my balcony.

    I’m also wondering if I could keep my original bin half full, covered with newspaper to prevent air exposure, and do smaller quantities. I found the full bin too big for my waste.

    1. Hi Eliza, you can thoroughly mix up the fermented bokashi waste with your soil or compost then cover it with a layer over the top to speed up the process.

      Your bokashi bin has to be sealed airtight until it’s ready, covering with newspaper won’t be enough, the lid needs to be on firmly. Bokashi bins come in various sizes, the small ones are quite compact.

      1. Excellent! That’s great news, thanks for letting us know that it worked! 🙂

    1. If the bokashi hasn’t worked, it will still be a mix of the ingredients, and what’s in the mix makes all the difference.

      There are two possible scenarios here:
      1. The bokashi mix contains ingredients which can’t be composted, and you’ll be trying to compost them, which is not a good idea!
      2. The bokashi mix contains only ingredients which can be safely composted, and you’ll be trying to compost, which is not a problem, bit they’ll compost faster in a compost bin

  3. What should I do if there are maggots in the soil factory? I had maggots in my precompost bokashi bucket in which I thought they would just die if I put themm all in the soil. But the maggots are still alive and it has been 2 weeks since I mixed them in the soil. I have seen them a few times at the top of the soil when i opened the lid and then the next day, they disappeared back down the soil. Should i pour boiling water into the soil but this might affect the good microbes of the soil?

    1. It’s important to let the bokashi bin contents to sit for a week before using them, this ensures that they’re completely fermented and won’t attract pests.

      How did maggots get into the bokashi bucket? The fermentation process in anaerobic, that is, it only works in the absence of air, so the lid should be sealed all of the time. If you leave the lid off the microorganisms in the bokashi mix cant do their work.

      That said, if maggots got in, just bury the bokashi all in the ground, it will continue fermenting and flies can’t live underground!

  4. Hello!
    Does the Soil Generator have to have drain holes? I’m sure there is a good reason they need to be there, so just curious. We live in an apartment with a large tiled courtyard, but not lawn or soil ground. Maybe I could put a large saucer or tray under the BSG to catch anything that drains? Just don’t want to ruin the tiles.
    We’ve been successfully making bokashi scraps for awhile now, and are keen to produce our own soil now for pot plants and eventually large planters we’ll be getting.

    1. Hi Amy, the drain holes are just there to release any excess liquids to prevent the end product becoming waterlogged when the bokashi mixture breaks down into soil. You could possibly just place a tray of some sort underneath so you don’t stain your tiles. If you give it a go, please let me know how it goes. Thanks, Angelo

  5. I took inspiration from this article as my soil is clay/rock and took much effort to dispose of my 15 liter Bokashi bin contents.

    I am blessed with much garden waste and put a significant amount through a 5HP chipper/mulcher. I double chip the waste to make it fine (decompose quicker) and place 3 pitch forks of this along with the Bokashi bin contents into a 220 liter plastic compost bin. Once mixed through the Bokashi contents disappears in about 2 weeks. The compost bin generates significant heat (happy microbes)

    I keep filling the 220 liter compost bin as above till its full and then leave it alone for a while. Worms appear in 4 to 6 weeks in the compost bin. I then put on veg garden. Pretty quick low grade compost.

    I have two 220 liter bins which I rotate (one filling and one I draw down). Make shure you cover the bottom of the bin with 1/2 inch wire mesh and fold this around the bottom 10cm of the bin to keep rats out.

  6. Hello, greetings from Germany. I enjoy your blog a lot. Very scientific, with a lot of valuable advice and not full of garden myths like so many others, thank you very much. One thing that is concerning me: On your blog I read that a low pH level can dissolve aluminium from perlite. If I add earth that contains a lot of perlite to my Bokashi is there a risk that aluminium might get dissolved? And can this aluminium contaminate my vegetables?

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