Bacterial Decomposition of Compost and Meat

Bacterial decomposition of liquid compost including meat

This is not Bokashi, but for our needs and budget, it’s even better!

It is not reliant on continual purchases like Bokashi systems are, and it is also not reliant on strip mining minerals the way most commercial synthetic fertilisers are produced.

This method works great and it provides a continual source of plant nutrition, improving our rocky rubble soil at the same time turning waste like weeds meat scraps and lawn clippings from rubbish into a very valuable resource.

I started with a 500litre rainwater tank with a well-fitting lid. I then made a large sock shaped filter out of 6 layers of 90% shade cloth. The sock is twice as deep as the tank so it bunches up in the bottom heaps.

That means there is about a foot of scrunched up shade cloth in the bottom of the tank for improved filtration and it also gives a much larger surface area for the bacteria yeast and fungi to grow on. Surface area is very important with this system, as is continual use to turn and stir the water content oxygenating it.

When I wasn’t using as much meat and all of it being from the supermarket scraps I had regular dramas, but once I started using whole roadkill all the smell issues stopped. I suspect it’s the gut content of the kangaroos and wallabies that provides the best starter culture as when I didn’t have them that’s the only time it ever became an issue?

I can tell that if you do get a build-up of the wrong bacteria, the tank stagnates, anaerobic bacterial decomposition takes over and at that point, the culture dies making the stink truly incredible! Aerating by stirring the liquid will reverse this and in a couple days the smell is much less offensive. The best way to do that is to drain a few buckets of liquid from the bottom of the tank and pour them back over the top as often as is practicle.

Regardless if you have close neighbours, kids that can’t leave things alone or you live in the city, then this probably isn’t the right system for you…

  • By rough volume(litres not kilos), we always aim for about ~40% water.
  • ~40% fresh green weeds and lawn clippings
  • ~10% is roadkill, fish, meat scraps, bones, eggshells etc
  • ~5% ash from the fire to increase alkalinity but if you don’t have a regular supply of wood ash then a cup of lime powder will help every now and then.
  • ~5% household compost like citrus peel, tea bags, paper, fruit and vegie scraps, onions, mouldy rotten food, and/or whatever else I can find.

Oh yeah, that skippy in the pic was a victim of the local roads, not by me by the way.
I see a dozen every week on the way to town so back in the day I figured why let them go to waste? I just tied it to the roof racks and brought it home for the tank. It worked even better than I had expected and luckily/unluckily there is an endless supply of them on every rural roadside in the country.

We can drain the tank of half its fluid content every 1-3day and then dilute it 1 part juice to 4-5parts water. That gives a lovely brown fluid that is teaming with life and we use it as a tonic type of thing. It isn’t a fertiliser as such as the nitrogen content is mostly used up by the billions of bacteria in the tank. Think of it more like a trace element multivitamin for your soil.

It’s more like a worm wee, fish emulsion, seaweed emulsion type of thing, and for obvious reasons, it should never be directly handled or used on plants you will be harvesting in the next couple months. It’s great for a post-harvest soil feeding, or for activation of compost heaps, and for speeding up the decomposition of woody mulch.

Once the content of the tank has started to collapse you can just keep topping it up with more weeds, scraps, road kill, along with a little more wood ash, and once you have it cranking it’s pretty amazing how much wasted life can be digested and turned back into soil and plant food. The difference it makes to the soil texture and water holding ability over time is truly amazing.

When the tank eventually fills with insoluble plant fibres, animal hair and bones it is then just drained and poured back onto itself for a few cycles until the juice starts to become pretty clear.
At that point its nutrition is pretty much all used up by the bacteria and they run out of food dying off. Then it’s ready to be emptied out.

The liquid is left to completely drain out for a week to make the shovelling easier and amazingly the volume of solids drops by about half. That sludge, soil, mud sediment stuff in the bottom of the tank can be used to line the bottom of the next raised garden bed. I also dump a scoopful here and there around the base of our trees.

By this stage it doesn’t smell at all, and the bones and feathers are really soft like wet chalk. The best way to describe it is like the bones in a tin of tuna or sardines and if you were really keen you could easily crush them up with the shovel. Being lazy I normally don’t bother as the majority will be buried anyway, and within another couple months underground there won’t be anything left at all except an awesome garden!

Worth considering, but definitely not for everyone.