Biochar and bokashi = great combo

Anyone here know about biochar? I’m in Myanmar and they’re using a lot of biochar made from rice husks as a potting mix base. I’m not sure how they’re making it; if its real pyrolysis (sort of burning it without oxygen). How can you tell, do you know?

Time to stop using peat!

From a broader perspective, it would be great to stop using all this peat moss in potting mixes, as we’re doing in other parts of the world. Crazy.

You can obviously make biochar with a lot of different materials but what is often not talked about is that you have to charge charcoal or whatever with nitrogen before you dig it down in the ground. Otherwise it will take the nitrogen it needs from the soil and your plants will suffer.

Good quality charcoal is great in combination with bokashi. Used in a bokashi bucket it will absorb a lot of excess liquid, which will also load it with nitrogen. This means you can use a bucket without a tap if you want (cheaper, easier). Microbes love hanging out in charcoal and I’m assuming the same holds for other forms of biochar.

And biochar is a great soil additive, balances moisture and nutrients in the soil and works really long term.

If you’re going to use it in a bucket, crush it a bit first (charcoal is often made for cooking purposes and is in big chunks). That way the microbes can get it easier and there will be fewer air pockets.

Check your source!

Oh, and another thing. Check that the source of your biochar is ok, especially in the case of wood-based biochar. Ethical forest and all that. Makes no difference to the microbes but all the more to the planet.

Any thoughts on this? Have you used biochar in your soil?

Footnote: we had an interesting discussion on our facebook page Bokashiworld this week, a lot of good input from Walid Gabr who has done a lot to spread the bokashi message in Egypt and the Middle East. Here’s a link to the discussion.

These were a couple of biochar videos he recommended, they’re good!

3 thoughts on “Biochar and bokashi = great combo

  1. Hi Jenny
    I’ve been using bokashi and biochar for 18 months now.

    I make my own biochar on a small scale from my own garden prunings and fallen wood. I use a woodgas stove, and simply quench the char when the gas flame dies out. Preparing the wood is time consuming, so I’m thinking that I might switch to buying in.

    At first I used to add crushed biochar to the bokashi preserve before digging into my soil factory. Mixed thoroughly, this both charges the char and kickstarts oxidation of the lactic acid in the preserve, which is the bit that makes bokashi edible and attractive to soil creatures.

    Recently I’ve begun to use the bucket method, about 3-4 cm in the base to absorb liquid. No further additions because they’d stop acid percolating down and preserving. This is exciting because it opens up much cheaper and larger scale operations than the commerical buckets.

    Right now I’m also trying to make a bokashi starter by fermenting molasses / treacle / syrup in biochar. I’ve got the white mould but no characteristic odour, so low probability of success at present.

    Do you realise that every kilo of biochar buried in soil equals 3.6 kg of carbon dioxide permanently locked away and unable to get back to the atmosphere? However, using it as a peat substitute is not something I’d recommend, because such high concentrations don’t do well in trials. Better to apply what you have thinly over wide area.

    1. Malcolm, thanks! Really nice to share your experiences.
      This that you wrote about
      ”Recently I’ve begun to use the bucket method, about 3-4 cm in the base to absorb liquid. No further additions because they’d stop acid percolating down and preserving. This is exciting because it opens up much cheaper and larger scale operations than the commerical buckets.”

      …was really interesting. We’re thinking of trialling bokashi this way in Myanmar (I’m in Yangon at the moment). Wood charcoal is readily available, how much should we crush it? Powder or small chunks? I’m really not sure about the rice husk char, need to have a good look at how they’re doing it. But if it looks more like char than ash maybe its ok?
      And yes! The carbon sequestration thing is soooo important, and my favorite rant and rave topic!
      The peat thing: we just need to find ways of building soil organic matter without buying peat, I guess its a combination of everything, bokashi especially.
      Really curious where your experiments take you, let us know!

      1. Happy to help. Crush the char as much as you can but don’t obsess over it. You’ll get a mixture. What matters most is that the carbon gets into the soil. Only fine bits can pass through worms (who eat them for the bacteria on/in them) and be charged with their contribution. Small fragments help soil texture no more and no less than small stones, plus they still retain moisture. Obstinate larger pieces probably aren’t fully pyrolysed, but hey, even they are still organic and the fungi will get them in the end.

        The same applies to rice husk char. You’ll have a mixture of ash (nutrients), very fragile char and maybe some original plant matter. Sounds good to me, especially as a bokashi base layer.

        Ideally you want a human-powered crusher, made efficient by lever, handle or even one of those African pile drivers used for pounding grain. I’d be happy to have any of them to replace my pathetic DIY setup. Some suggest a powered garden shredder. Mmm … does really it do a good job and what about the carbon emissions?

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