Farm&Garden > SoilAmendment > Bokashi > bokashiTrenchBokashi Trench
Click the 'See the process' button below for a more complete picture of what happened and my thinking.
A Bokashi Trench is just a hole dug in the ground and filled with your finished bokashi, and something to help in the digestion. I added fresh compost and some worm juice and their casting to get the biology going.
I was worried about my local pests (squirrels and rats) digging up the trench and making a huge mess every day. The pests do seem to dig the pile up the day after I bury it, but only pull up a few pieces before realizing the food is unpalatable, and quickly leave it alone. The deeper you bury the food, the less pests seem to bother it (probably because of the smell).
One problem I did notice is wasps and flies LOVE finished bokashi, and will lay larvae in it whenever possible. This could turn into a huge mess if left uncovered, so rebury it as soon as possible. This seems to kill the larvae.
It took about 2 months for the food to be completely digested. All that was left was some larger bones and tomato skins.
I had imagined the soil would be closer to a rich compost when finished. Better at retaining moisture and full of organic matter, but this wasn't obviously visible. While the nutrients have gone into the soil, It don't feel like there is a finished product after all that work. The soil doesn't seem any different that before I buried it.
If you only want to add nutrition to your soil, this seems to be a good method, but if you are looking for a final product to add to a raised bed, or something to add water retention, this is no compost.
See the Process:
In itself, running food though a bokashi bucket doesn't decompose food. You are basically pickling the food and retarding further decomposition. While this seems like the opposite of what we want, it also makes it unappealing to most pests who would love to get their paws on it.
Almost every compost tutorial will advise you do avoid dairy and meats, baked goods and acidic or greasy foods. (one notable exception to this I love is Geoff Lawton who's mantra is: If it has lived, it can live again, but I don't think he is worried about upsetting neighbors out in Australia).
Unfortunately, these 'banned' foods are high in nutrients and good for the soil.
I have seen people suggesting burying the finished bokashi directly into your garden, so I though I would give it a try. You should avoid burying it under trees because of the acidity (which was my first thought... bury it under some trees at the back), so I placed mine in the main garden bed that I am rehabbing while I focus on the SFG. There is a Ash tree right beside it that was cut down a couple years ago. I have been practicing coppicing and pollarding it but am not overly concerned with it's health.
My process was super easy. Dug a hole about a foot and a half deep, dumped the bokashi directly in, and covered with compost, worm juice and worm castings. Might have got a couple of worms in but didn't specifically try to. I mixed it all, and buried it under the normal clay soil.
Not much to see in this image, but I am notorious for setting things up and forgetting where I put them, so I have marked the location with two sticks. This should make it easy to see if creatures are digging for the food.
Articles I have read suggests it should be ready for planting in 2 weeks, but I am doubtful. When others have dug them up they look fairly similar to when they went in months later.
Our garden soil is almost completely made up of clay. (inherited from the previous owner). I tried a modified 'Ruth Stout' method which seemed promising but in the end didn't seem to help the soil. It's also very dry being in the direct sun and no ground cover (yet), so I'm putting the auto watering hose over it.
One thing I am worried about is animals digging up the beds. Squirrels eat everything and dig up my garden daily. Apparently my city has a bit of a rat problem right now, so I'm not exactly sure who is doing what, but we will see if I need to add a cage.
2 day update
Yesterday and today some pest dug into the trench and pulled up some of the food. They didn't seem to eat much, more investigating.
2 day update
The squirrels stopped digging after 2 days. I was curious what is going on after the suggested 2 week wait, so I dug the trench up. It seems like nothing has happened. Looks like when it went in.
2 month update
We went on vacation for a month, so I was excited to see what happened when we got back.
When I dug down into the trench I though I might have the wrong spot. There was no trace of any of the food at first. Eventually I found 2 larger bones, and some tomato skins, but that was it. No evidence whatsoever I had buried anything there.
While this might seem good, I had hoped it would condition the soil a little, add a little compost, open up the soil a little, or help in water retention. But there seems to be no change.
On this first try, the trench method seems a success dealing with finished bokashi if you just want to be done with it. It has probably improved the soil, but not as much as I have wanted.
I think a better option would be to use the finished bokashi in a hot compost pile
I am thinking of digging a second trench and adding some worms, maybe a combo of Night Crawlers to dig the bokashi nutrients deep and Red Wigglers to speed up the process.(I must admit to waffling back and forth about the problems with Red Wigglers).