Bokashi

What is the Bokashi composting method?

The Bokashi method of composting is a clean, convenient way to prepare your kitchen scraps or garden waste so that they will be broken down more quickly and more completely when added to existing methods of composting or directly into your garden. It also allows you to add meat, dairy and small amounts of oil to your compost without the usual issues.

Before compiling all of this information, I first wrote about Bokashi in Grass Roots Magazine No. 261 Oct/Nov 2020 called ‘Buckets of Bokashi‘. It’s worth a read as an introduction to the topic. I’ve learned more since then and this page and it’s associated pages are all I know so far.

One of our Bokashi bins.
One of our Bokashi bins.

Bokashi seems to stem from the methods of Korean Natural Farming and was released as a commercial method, developed by Teruo Higa in 1982 under the ‘EM’ trademark (short for Effective Microorganisms). It is clean, pest free (as long as the buckets are kept sealed) and odour free as long as spoiled materials aren’t added.

The system uses an airtight container with a tap for drainage. To this container, you add your kitchen scraps and a little of either a microbe rich solution called EM1 (for ‘Effective Micro-organisms 1) or some bran that has been inoculated with the same microbes. These microbes are anaerobic, meaning that they thrive in oxygen poor environments. To give them such an environment, you push down the scraps and microbes in the container so that air is excluded. The airtight lid helps to keep air out. A large proportion of the microbes are strains of Lactobacillus bacteria. That’s the kind that curdles milk and are common in Kefir and Yoghurts.

Commercially made Bokashi bins are quite expensive and the EM1 solution or the Bokashi Bran are ongoing expenses but you only use a quick squirt or a pinch depending on which you’re using so they do last a while. This website has a few of pages that detail things we do to extend the commercial stuff or make our own from scratch, They are –

How does it work?

Bokashi is, essentially, a fermentation system which uses microbes to ferment and pre-digest the scraps on which they live. This generates a microbe and leachate rich liquid that must be removed occasionally (more on this later) and the fermented scraps which are then moved on to another system of composting or simply buried in your garden.

You keep adding kitchen scraps and microbes, pressing down to exclude the air each time you do so. Every couple of days, drain off the leachate and keep it somewhere. It is very useful as you will see.

When the bin is full, you put it in storage for two weeks to allow the microbes to do their work (longer in cold weather). It’s generally best to have two bins or at least one bin and a container that you can seal and in which you can empty the bin. This container will need a tap or some other method of drainage. Then you start refilling the bin again.

Make sure that the lid is kept sealed when you’re not adding your scraps. You want to keep as much oxygen out as possible. There are three ways that we can do this. First, we don’t open the bin every day. We collect up small amounts of waste from cooking and meals and put them into a small container. We add this to the bin only when its full. This means that we’re not opening the bin every time we have a scrap of food.

The second way is to keep an inflated ziploc bag in the bin. The volume of this displaces air so that there is less in the bin. As the bin fills, you can gradually deflate the bag until it is not necessary. The third option is similar if you are using bran, Simply keep the bag of bran, sealed of course, in the bin so that it can displace air until the bin starts to get full.

How to use the finished product?

After the two week rest time in which the microbes have had a great time digesting the bounty you have given them, you can use it.

When you open the bin, you will be greeted with a vinegary smell which is characteristic of fermentation. If you do any other fermentation in your kitchen, the smell will be instantly recognisable to you. The kitchen scraps won’t look too different to how they did when you put them in. They may be darker and softer and that’s good. There may be a little white mould and that’s OK but if you have a green mould check the problem solving section below.

Compost

The Bokashi scraps can be added directly to an existing compost heap, bin or tumbler. The microbes will help kick off or re-invigorate the heap very quickly. The anaerobic microbes will find their niches in amongst the compost material or will die in the presence of oxygen and will provide a ready supply of food for the organisms living in the heap. The partially broken down scraps will be an easily accessible supply of food for them too and will literally disappear after a few days.

Worm farms

Worms love Bokashi scraps for the same reason that critters in compost do. They feast on the microbes and enjoy the easy access to the organic materials that have already been prepared for them. The acidity can be a problem though if you’re adding too much too frequently. Check out the problem solving section below.

I’ve added Bokashi scraps to our worm farms in Winter and have noticed the beds warming up within a few hours.

Chickens

Our chooks love to eat small amounts of Bokashi scraps so I throw a couple of scoops into the run whenever I’m emptying a bin. They love it and eat it quickly with much clucking and trilling showing their happiness. It didn’t take long to work out the right amount for our flock. I suppose that it’s similar to giving them fermented grain and gives their digestive tract a boost. Give our girls too much and they will just ignore it, as they will if I give them some every day. Once a week or so is fine by them.

Pot plants

Plants in pots like Bokash scraps too. You mix a handful into a large sized potful of potting mix and watch your plants thrive after planting. Some folks say that they add the scraps later as well but I’ve not tried that.

You can add some of the leachate to water at a rate of around 50:1 when watering the plants as well.

Pets

The jury is still out on this one. Athena just loves to steal scraps from the Bokashi bin while I’m composting it or feeding it to the chooks or worms. If she gets a little, all is good but Labradors being Labradors, she will eat it while it is there. Then we’re up to our knees in sloppy dog poo for the next few days!

We get a lot of ‘gifts’ from Athena anyway and have worked out a way to Bokashi our dog poo. There’s a whole page on our Bokashi Dog Poo system on this website, {link to dog poo page}

Pests

Bokashi allegedly deters pests such as cockroaches and rats. I’ve spoken to many people who swear that this is true but haven’t really put it to the test here in Ligaya Garden,

Bokashi leachate

The leachate that you drain from the bottom of the bin every few days is like liquid gold. It is quite acidic and full of microbes and their waste products as well as the juices that have drained from the kitchen scraps.

It can be watered down 50:1 and applied to pot plants and garden beds. Its microbial richness and acidity make it an excellent way to keep your drains clean too. SImply pour some into your shower and sink outlets a few times a week once everyone has finished using them for the day. The microbes will go to town on the hair, soap residue, skin and blood particles and general dirt and body oils that can easily clog a drain. Keep adding it for a little while and you will notice that the drains no longer clog, no matter how many teenagers may be in your family!

We spray a 20:1 solution into the chicken house while we are cleaning it and spray a little into the nesting boxes from time to time. This helps reduce odours and, I reckon, keeps the chooks happier.

A 100:1 solution makes for an effective bug spray when sprayed over infested plants. The microbes and acidity change the environment on the leaf surfaces, to the detriment of the pests.

Problem Solving

Bokashi is relatively problem free. There are only a few things that can really go wrong and they are –

Too much oxygen. The usual cause of this is an ill-fitting lid. As mentioned earlier, Bokashi microbes are anaerobic, that is they don’t like oxygen. Too much oxygen will kill them and allow aerobic (oxygen loving) microbes to take over. This will result in smells and green mould forming. Be extra careful if you see mould on the surface of the bin’s contents.

Too much moisture. The most common cause of this is failure to drain the bin enough or regularly enough. This will lead to a sloppy batch and a very strong smell. The other cause is adding too much wet material like soups or oils. If you are likely to do this you are better using the bran rather than the EM1 spray or adding shredded paper whenever you add your vegetable scraps. This will help absorb some of the excess moisture.

Green or black mould. These are usually caused by oxygen in the system. They are easily dealt with by removal and disposal or burying the mould further into the contents of the bin . Be extra careful if you see moulds in your bin, disturbing them can cause them to release clouds of spores that may trigger sneezing, coughing or other respiratory problems in those with existing health issues. I lay some wet paper over the mould before disturbing it.

The dreaded green mould
The dreaded green mould

Bad smell. Bad smells aren’t a usual part of the everyday Bokashi experience. They usually come from the addition to the bin of materials that are already spoiled or rotten or materials that, by themselves, already have a strong smell.

Flies. Generally, the air tight lid and freshness of the scraps that you add will keep flies out of the system. Sometimes, though, you may add something that’s been sitting around for a while and has fly eggs on it. If you fill and swap your bins frequently, they won’t have time to hatch and grow before they’re out in the garden away from you.

You can also get insects in the system if your lid is not closing properly or is cracked. This can lead to the presence of maggots from house flies or some of those tiny, black, vinegar flies. Just put the contents of the bin out to your chickens or into your compost early and start the bin again after a good clean and check over for cracks or warping that is creating gaps.

Other problems can sometimes occur if you are running a system with three or more bins like we are and, especially in Winter, when the garden and compost heap aren’t so active and the bins back up and aren’t empties as often as they should, The scraps and microbes can produce a lot of liquid and over ferment the contents of the bin. This will produce a very sloppy mix and a strong smell that stays around if you get it splashed on your skin. Burial is really the only option for this if you have the space in your garden. Failing that, mixing in straw or sawdust can dry up some of the sloppiness as well as add extra carbon for when the scraps reach your compost heap.

There is one little trick to disposing of a bad batch of Bokashi if you have the time and space and that is to Bokashi it again. Even the dreaded green mould will succumb if the batch is treated like another batch of scraps and More Bokashi bran and fresh vegetable material added. This takes one or more separate buckets though and more time. Probably best t to bury it…


If you’re interested in learning much more or would like to participate in a program of Bokashi composting, check out our friends at Bokashi Pinoy and their self paced, hands on, fully mentored 30 Day Garbage to Garden Challenge.

Bokashi Pinoy
30 Day Garbage to Garden Challenge

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