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Bokashi in Science Class


February 19, 2024

Hello, I am an 8th grade math and science teacher.  I missed the Bokashi class, but hope you can answer some questions.

Description of Setup: I put some brown rice in water and waited for it to begin bubbling from the bacteria in it.  I transferred this water into milk.  I waited for the milk to separate into curds and weigh next to other milk that had not been treated (it had smooth curds while the treated milk had curds pocked with gas bubbles a little like Swiss cheese) with rice bacteria.  I poured the liquid from both solutions into a mixture of water and molasses as per an online recipe.  I then poured that onto papers and coconut coir as that was what I had on hand. It is now in a bucket. I have needed to bleed the pressure off every day for the last several days (I am a little surprised this gas does not smell).

I hope to get a bucket of food and layer it with this wet bacteria and coco/paper substrate in order to pickle the waste.  However, I do not understand a couple of things about this process as it has been described.

1. If I put it into a bucket, I am to understand I want anaerobic conditions.  If this is the case, then why should I drain it during the process?  I would think the extra liquid would take up space otherwise filled by air.  Is this a pH issue or something?

2. The soil I have to bury the bucket in is very sandy.  Do I need cellulose like in normal compost?

3. Are there any issues with my method as described above?

4. Are there any good programs or grants you are aware of to encourage gardening/composting in schools?

Thanks for your attention.


Answer by JZ: I will let other master composter colleagues answer your Bokashi question. Here is teachers resource list  from 2016, but still useful, I hope. Keep up with your efforts.

Answer by RB:  You may get several responses to your query as it is sent to a number of our members. First, let me say you have put a lot of work into this and it will be interesting to see how the food scrap fermentation goes.  I normally use EM1 from Teraganix and molasses to inoculate wheat bran, ferment this, then dry it so it will keep a long time and can be used to introduce the microorganisms into your food scraps as you layer them in the bucket.  However I have done some research on creating your own inoculant, as you have done, and also capturing and using indigneous micro-organisms.  There are many approaches and I cannot speak from experience on very many.

That said, lactic acid bacteria (LAB), yeast and purple non-sulphur bacteria(PNSB) are the organisms that encourage fermentation in Bokashi.  I’m sure your mixture will have lots of LAB, and some yeast acquired from the air.  I’m not sure about the PNSB which may or may not be an absolute requirement. To some extent, all composting methods involve some experimentation to find out what works for you. I would suggest you combine your mixture with wheat or rice bran, both of which are quite inexpensive and easer to manage and store. Wheat bran can be obtained at any feed store, $15-$18 for a 50# bag. 

I think the gases you are releasing don’t smell offensive is that this is a fermentation process as opposed to putrefaction, although both are anaerobic processes.  The liquid that drains off at the bottom of the bucket  tends to go aerobic and begins to stink—it makes great drain cleaner, however, because of the acidity.

You should be able to bury your end product directly in the sandy soil, but mix the soil and fermented material together—at this stage you want the microbes from the soil to move in and take over the decomposition process aerobically.  No need to add carbonaceous materials as you do in other composting processes.

There are grants and such out there, but I’ve not done any research on it, so I can’t give you specifics.

Let me know how your efforts turn out.  You should be able to see results in a relatively short time.  Keep in mind that you need to let the soil microbes work for awhile (2-3 months) before planting.

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