is nitrogen reduced

Michael j McCluskey asked 5 years ago

Are the nitrogen levels of finished bokashi reduced compared to untreated food scraps? Does bokashi waste promote aerobic composting and increased pile temperature?”

7 Answers
Nicki Casley Staff answered 5 years ago

Hi Michael,
Thanks for your insightful questions.
Firstly, your question about nitrogen. The bokashi fermentation process occurs in a sealed bokashi bucket meaning that none of the nitrogen (or other elements in the food waste) can escape. So the nitrogen levels in the fermented bokashi food waste will be the same as that in the original untreated food waste. While the total amount of nitrogen does not change, the form can and often does change. For example, some of the protein is transformed into mineral forms of nitrogen during the bokashi fermentation process.
Secondly, how bokashi helps your aerobic compost pile. Fermented bokashi food waste provides a great source of food to the ecology within a compost pile. Adding bokashi promotes a large increase and activity of soil organisms. The bokashi pre-compost is often damper than the moisture content recommended for hot composting. Pile temperatures will likely not increase immediately, as the bokashi will need to dry slightly. During this time there may be pockets of anaerobic activity in your compost pile. But don’t worry, this is from the healthy bokashi anaerobic microbes.
This graph shows effects of bokashi compost on pile temperature with the main peak in temperature occurring after the first turning.
I can also vouch from personal experience that bokashi pre-compost is great for compost piles. My compost pile is absolutely teeming with life and materials are breaking down a lot faster since I have started regularly adding bokashi pre-compost to it.
Hope that is helpful. Please ask any other questions you have about bokashi composting.
Happy composting
Nicki and the Bokashi Living team

Malcolm Fowles answered 5 years ago

Nicki, what’s your rationale for adding bokashi to compost? Here’s my rationale against …

As any ecology textbook will tell you, the amount of energy input to an ecosystem determines its size. In organic growing, plants can only feed on minerals released by the soil ecosystem. Therefore the end goal of any soil feeding method is to feed, enrich and diversify the soil ecosystem.

The energy in food resides in its chemical bonds. When food waste decomposes, over half of the bonds are lost (if aerobic) or over three quarters (if anaerobic, like most domestic composting). Decomposition releases to air the majority of input energy and organic carbon as heat & CO2 (if aerobic) or as methane [CH4] & CO2 (if anaerobic). In contrast, bokashi fermentation loses almost no chemical bonds, especially not carbon bonds; rather it restructures them. Hence, bokashi is more than twice as efficient at delivering energy and carbon to the soil ecosystem.

Both methods should deliver similar amounts of nutrients. This is largely true, except that decomposition can lose some nitrogen, in ammonia gas; and in open composting systems it leaches nutrients onto uncultivated ground (an argument for not using fixed bins or heaps). Hence bokashi is a bit more efficient at delivering nutrients too.

Therefore, in adding bokashi to a compost bin rather than direct to soil, you are effectively letting more than half of its potential benefit, sometimes much more, leak away to air and to any soil under a fixed heap.

You might also think that the energy and carbon will be lost as soon as the soil creatures eat it, so who cares. But that would be to misunderstand ecosystems. Once they’ve got energy, they hang onto it as long as possible. Waste matter and dead matter are cycled around the soil food web.

If only there were a way to include all green garden waste in bokashi! …

Kind regards

Nicki Casley Staff answered 5 years ago

Hi Malcom,

Thanks for the response. Adding bokashi pre-compost directly to the soil is many people’s preferred approach. As you say, bokashi works very effectively this way and is also often the easiest method (saving double handling of the compost). However, we also know that many people like to add it to their compost pile too. There are situations when it is not possible to use the trench method, for example, when the ground is frozen or covered in snow. In these instances, adding the bokashi pre-compost to an existing compost pile is a great option. Other people may have slow or failing compost piles and adding bokashi pre-compost to them can help to reinvigorate the heap.

To me, one of the great things about bokashi composting is its versatility. I add my bokashi pre-compost throughout my garden depending on the time of year and where its needed; my compost pile, directly in my soil, in my planters and containers and also in my soil factories πŸ™‚

And I agree… if only all green waste could be bokashi’d! And if only everyone bokashi’d all their food waste…. so much healthy soil!

Thanks for spending the time and adding your valuable knowledge to the discussion.
Happy composting

Nicki Casley Staff replied 3 years ago

Hi Paul,

Thanks for questions. Ideally, the bokashi’d food waste should be mixed with soil or compost so that it is readily assimilated into the soil. I understand your reasoning for a no-dig gardening approach. To avoid disturbing your soil and root layers, we would suggest you keep adding it to your compost pile and applying the finished compost to your garden.

We do not have experience of blending bokashi pre-compost and applying it directly to the surface of the soil. If you do try it, we would recommend adding a thick layer of leaves or mulch on top. This will stop the pre-compost from drying out and forming a crust on your soil. It will also act to deter any inquisitive creatures. Also, make sure not to apply too close to plants as the bokashi pre-compost is fairly acidic (like the bokashi tea). We would be interested to know how you get on.

Happy composting πŸ™‚

Paul merkelson replied 3 years ago

I have been recycling my food waste for several months using the Bokashi method, and have filled (4) 5 gallon buckets. One bucket I added to my cold compost and it did seem to invigorate it. I have used that in the garden and will continue to add The Bokashi fermented food waste To my compost for the time being. I am persuaded by both Malcolm and Nicks comments on FFW in compost. I have also trenched in 2 buckets into my vegetable garden. I want to avoid disturbing The root layer as much as possible , so I do not want to continue to trench in the FFW. In addition I have a small Suburban property and will run out of plots to trench.
In your opinion can the FFW be liquified and applied directly to the soil. Does it need to decompose first? Will it lose nitrogen and other nutrients If it’s applied on top of the soil? Should it be diluted as recommended for Bokashi tea? Can Bokashi tea be Used in the liquified FFW? Any recommendations for a large immersion blender? Kitchen sizes seems to small and a paint mixer may not be sharp enough
Many questions. I appreciate your thoughts

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