How to Compost Bokashi

This week in the Flog:

  • Composting of Kitchen Scrap Bokashi
  • Final Composting Article of the Series

I just love composting. There are so many different ways to compost – whether you are using critters like worms, cockroaches, or BSF larva, or some anaerobic method like bokashi, or you are just composting traditionally with a combination of green and brown ingredients.

My compost pile out on the balcony has been steadily growing as I’ve practiced all these composting styles and added them to it. It’s exciting to see, and the pile looks amazingly rich.

I have one more thing to compost before I apply this to the garden. My bokashi bin I’ve been using for kitchen scraps is getting quite full. I need to empty it, and the compost pile is the perfect place. Why? Because bokashi is not finished compost. You can add it to your garden, but it still needs to break down before it’s available to plants. Also, as a top dressing, it is vulnerable to critters, who universally LOVE fermented food. Animals sense a healthy meal apparently. So if you DO apply bokashi directly to your garden, watch out for that – better to bury it a few inches in the soil.

I’ll compost my bokashi since it is packed with great nutrients which I’d like to include in my compost mixture. But first let’s take a look at a compost tea that was brewed to be applied to the pile with the bokashi. A good microbe rich compost tea is essential for a really good fast-acting compost pile. Here is the tea brewing:

Composting Bokashi - Compost Tea

Super microbe rich compost tea ready for the pile

The foam is due to some excess proteins from the fish hydrolysate I added – not a big deal and a great sign of active microbes (of course I check all the teas with the microscope to be sure of the microbe populations). You can do a lot with the fermented extracts, particularly BIM, to help speed up and enhance composting; but you can’t beat the power of a good aerobic compost tea, for introducing populations of aerobic microbes to your compost pile.

Let’s take a look at the bokashi compost. Here is the bin. It is basically just two 5 gallon buckets stacked up – the top is the bokashi fermenter, while the one beneath captures the leachate. I’ll have a separate article on how to make your own bokashi bin.

Composting Bokashi - Bokashi Bin

Simple homemade bokashi compost bin

If you look in the bokashi bin, you can see the fermented materials – fish, calamansi rinds, vegetable trimmings, etc, all the high energy scraps from the kitchen. All looking pretty monochrome and fermented.

Composting Bokashi - Bokashi

This bin is full of bokashi composted table scraps

The compost pile, after getting all the garden trimmings a few weeks ago, is looking great. All that remains of the trimmings are the stalks and those are pretty soft now. This pile is going to be great:

Composting Bokashi - Compost Pile

The compost pile is looking pretty nice. The trimmings have composted except for some stems, which have become pretty soft

Time to unleash the bokashi. Here is the “leaning tower of bokashi” added to the compost pile. Almost 5 gallons of bokashi! It’s so much, almost too much for the compost to cover and mix with. It’s a bit moist for optimal composting, so the pile might need to sit for a while before heating up. Dry composting like this requires the proper moisture level – around 60% is fine. If you sqeeze a handful of compost, you should just a get a drop or two of water out, and the handful should clump a bit. Now, the healthy anaerobic microbes will help us here – if the pile is too wet there may be pockets of anaerobic space where anaerobes dominate which can be a bad thing (thus the rule about moisture level). But with all the healthy anaerobes in the bokashi, these pockets would be fine.

Composting Bokashi - Tower of Bokashi

The leaning tower of bokashi. A little much for my little pile – owe well.

Last step for the pile, mix it all up. I’m just mixing the bokashi with the compost really well, watering a bit with the nice rich compost tea, and leaving it to sit. Here is the pile after mixing (you can see the wire from the thermometer I use to capture the temperature within):

Composting Bokashi - After Mixing

After mixing in the bokashi, the pile has grown quite a bit. Can’t wait to see how the temperature goes on this one.

I covered the pile with tarp to keep the surface moist and shaded from sunlight. This is great for digesting the materials on the surface of the pile, that normally you would have to turn in to be composted. Some species of microbes, like actinomycetes, thrive in just that condition of the boundary zone where there isn’t too much or two little of any one thing. You can see here there are white “molds” that formed – those may be molds or may actually be bacterial colonies that have formed in the favorable conditions of the boundary zone. Either way, it is an excellent sign of a healthy compost pile:

Composting Bokashi - Mold on Compost

There is some nice mold on the compost by the second or third day. Signs of healthy action!

Lastly, let’s take a look at the temperature readings for this round of composting. You can see I let this go quite a bit longer than before, as it’s the final stage of my compost pile. I turned it a few times, mixed in fresh compost tea at those times and watched the temperature spike right after.

I think the pile was a bit too wet to start with – too much moist bokashi compared to pile. So it sat for a bit and the outer layers dried some. Then when I mixed, the moisture level was closer to optimum and the pile really heated up.

Note it only majorly spiked the first time I turned it, around 185 hours. The others didn’t have nearly the impact since the pile was already well digested by then. This is how to tend a fast acting compost pile, and the kind of response you can expect from it. The aerobic microbes are responsible for the heating of the pile, and by turning and introducing fresh populations, you can drive the process along at an accelerated rate. I love tricks to make awesome compost in much less time!

Composting Bokashi - Temperature Graph

Graph showing the temperature of compost vs ambient. You can see the second, greater temperature peak after mixing up the pile the first time.

And the pile, a few weeks into this round, is just TEAMING with organisms. Even visible ones, like pill bugs, are everywhere. It’s a healthy microbe-based ecosystem – it’s amazing to see so much diversity in the middle of the city.

There you go, the conclusion to the composting series. The compost looks incredible. Teaming with microbes. Filled with nutrients from the kitchen, from the worm bin, cockroach composter, and the garden itself. Of course this is overkill and there’s no need to do all the different kinds, but for demonstration purposes it was great.

Next step in the composting process? The post-script of the process – application! I’ll apply the compost to the garden and observe how the plants do with it. The garden is getting a little dilapidated these days and could use some revitalization!

I have a challenge for you. I want to know your composting strategy, and how it’s different from the ones I’ve covered in this series. I want to add to the list! Anyone up for the challenge?

  • jim triplett

    Hi Pat – how do you make the compost tea aerator? what are the ingredients to making the tea? is the blue pvc pipe connected to a recirculating pump and the smaller tubings connected to an aerator in the bucket? how long do you brew the tea? how is it used in the garden?
    thanks

    • Patrick

      Hey Jim,

      I’m covering all those in an advanced ebook/video on compost tea making. This will cover both aerated and anaerobic compost tea. Super interesting stuff, I can’t wait to share with you and everyone. I’m still working on it but will be out this year.

      Cheers,
      Patrick

  • Rodney Galarneau

    I compost in different ways at different times, during the winter I do bokashi in my basement. In early spring I spread the bokashi on top of my garden soil cover with a heavy mulch weighed down. During summer I spray bokashi juice on plants and collect the residue in 55 gallon drums which I put in place in late fall. When I was collecting large amounts of food residue from a organic food store I would place the residue in a wood box and chop with a sharpened spade and I would either bokashi or compost in place.

    • Patrick

      Excellent, thank you Rodney for sharing.

  • Leonie Stubbs

    G’day Pat,
    I’ve just started using a bokashi bin after passing on my worm farm to my daughter because I find I can use all my food scraps in the bokashi. However, my bokashi is not as broken down to the extent of yours by the time I bury it just under the soil surface. Have had no problem with dogs so far!

    Can you or your readers give me some advice re using green algae. I have a frog pond and I harvest a fair bit of green algae – I want to make use of it but don’t know how to do that. I don’t get enough to make oil but wonder if I can add it to my bokashi bin or use in some other manner.

    • Patrick

      Hey Leonie,

      Green algae will be excellent either in the bokashi bin or compost pile. Either mix with sugar and cover with a tarp to bokashi the whole lot, or mix with straw(or any other ‘brown’ carbon-rich substrate) and turn regularly to aerobically compost it.

      Cheers,
      Patrick

  • Hi Patrick

    Very interesting articles …keep it up.

    I make my own bokashi bran using wheat bran (I bought from bakery; have yet to try using the coco peat) + lacto (or EM) and molasses.

    The food scrap gets collected over time in my fridge ,haha . I then drain and mix with the DIY bokashi bran and store them in an air tight container (no drainage) in my storeroom. (I do by single batch only so that I don’t contaminate and introduce air)

    After three weeks I will remove the bokashied food scraps (I always smell the nice sourish scraps, haha), drain off as much liquid as possible (cos if don’t there is usually a lot of BSF) before thoroughly mixing them with some compost and soil.

    Then, I will transfer the mixture into a 5 gallon bottomless container so that there is contact with good fertile earth. (The so called soil generator method). I will add some 4 inches of soil on top before closing it up with a lid (not air tight!)

    I will harvest my DIY soil after three weeks. The soil still does not look fully composted and I set them aside at a dedicated (transition) corner on the ground (keep in contact with soil) but cover them lightly to give shade, prevent rain and to allow the composting to complete (so far the waiting period has been less than 4 weeks)

    The output is really nice soil… 3rd successful batch.

    Patrick, any suggestions to further improve?

    (BSF is supposed to help right, but then it always comes with awful smell; not putrefied but..unpleasant. Any clues, Patrick?)

    And thanks all the time.
    Elsie

    • Patrick

      Wow, excellent process Elsie.

      That certainly works for making soil from bokashi.

      You might consider adding worms/roaches to the system somewhere, likely at the bokashi stage. Can make excellent soil from bokashi pretty quickly using either of those. Also, what do you do with the drainage from the bokashi – you mentioned you drain off the liquid. You can capture that and add to water at a few tbsp/gal and it will be excellent fertilizer.

      Yeah BSF has some smell since they way they eat is so wet. Not much to be done unless you want to combine BSF and worms, that might work to keep the smell down. Also, spraying regularly with lacto should help the smell in BSF system.

      Thanks for sharing! Cool system!

      Patrick

  • Brad

    I can personally verify the above. My whippet can sniff out Bokashi compost from 200 metres! Whenever I bury some prior to planting, unless I close the polytunnel door, the whole lot will get dug up and eaten! She adores the stuff! However, it does absolutley nothing to improve her breath!

    • Patrick

      Haha yeah, in my experience animals go crazy for fermented stuff. Those in bear country beware…

  • priadi

    thank Patrick. That is very help me. I had try it, and the final is very good.

    • Patrick

      Your welcome Priadi, glad you are enjoying it.

  • Faizal

    Critters love bokashi. Would chicken love it too and is it suitable for them,?

    • Patrick

      Hi Faizal,

      Depends what ingredients you used to make the bokashi. If mostly grains, then go for it. But not so sure about table scraps, I think you’d be better off to leave the bokashi out for awhile, let lots of bugs get on it, then let the chickens loose on it, they’ll eat all the bugs, get the nutrients that way.

      Cheers,
      Patrick

  • Luke j

    Wow so many good articles here! Im going to soon start making the lactobacillus serum soon and then the bokashi bran for my good scraps. Then everything to the worm bin! Quick question: would you mind explaining how you created your compost tea brewer? It looks like one if the so called vortex methods or am i way off? I just use a bunch of airstones but my aeration never looks like yours pictured above! It would be awesome to see some pictures, tutorials, or links to construct this style. Thank you im also going to sign up for the mailing list!

    • Patrick

      Hey Luke,

      Great to have you on the site! Glad you’re enjoying our stuff. I spent a long time working on the design for my tea brewer, that one there is “2nd generation” i’m not on “5th generation” haha.. I’ll share all the details on compost tea brewing in a later post. If you’ve signed up for the Flog you’ll be first to get the info when I release it.

      Cheers,
      Patrick

  • Harley

    Has anyone made bokashi compost (anaerobic) WITHOUT using the bokashi bran? That is using carbon, kitchen waste and lacto-serum in a sealed bin. If so, how long was the bin left sealed?

    I like the idea of using an anaerobic fermentation to compost bones and manure, but I struggle with the concept of using sugar/molasses because 1. they cost money, and 2. I’m used to putting kitchen waste into an aerobic composter, which is free method.

    I know one of the concepts of this site is ‘experiment, experiment, experiment!’ but if you have an idea of how long an anaerobic bin should be left, I’d like to know. If fermentation is not complete, the stink will be truly awful.

    Also, if you have experience using alternative sugar sources, like fruit, I’d be interested in the proportions of fruit/carbon that you used.

    • Patrick

      Hey Harley,

      Thanks for the insightful questions. Note though, anaerobic composting won’t break down bones, and using manure in the system can be risky because it is dense with microbes already, the wrong ones can take over. Sugar helps with this because it’s an abundant food source which, in combination with microbial inoculant like lacto serum OR bokashi bran, enables healthy microbes to dominate.

      Yep you could do bokashi with just the lacto serum, I have done it with great results. In fact it was a bin full of water with some sugar and lacto added and then food just added to that over time, the fertilizer produced was awesome (STRONG) stuff. But I used sugar….

      In any case, you should leave your bokashi at least 4 weeks to ferment. preferably 6 weeks. Even in warm climate. If using fruit or straw, I’d mix in layers 1:1 with your food scraps. If you’re using fruit, use papaya!! Make sure to include the skins and if at all possible, the base of the stems of the fruit. These contain papain which greatly aids breakdown of your input materials. Fun stuff..

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