compost 01

18-Day Compost – the Appliance of Science

Composting puts carbon back
where it belongs
– in our soils!

You may have got beyond the ‘heave it in and hope’ stage of composting, but the average heap or bin still involves a lot of trial and error. This 18-day compost system takes the guesswork out of your heap and turbo-charges the whole process. But, it does require consistent effort for two weeks and careful monitoring to work properly.

Here’s how it was described to LeafTurner by Geoff Lawton, head of the Permaculture Research Institute of Australia. As part of Geoff’s academic research into the usefulness of this approach he has successfully composted the discarded bodies of a kangaroo, and even a penguin (both of which had died of natural causes). But it is not recommended you try that at home!

You will need:

  • a long handled fork
  • a rake
  • a minimum of 1m³ of semi-shaded floor space and room to work around it
  • a water supply
  • old clothes
  • enough compostable material to create a pile 1.5m high. One third of this should be manure (animal dung – horse or cow is good) and two-thirds carbon rich materials (also known as ‘browns’), which can include: ashes, wood, cardboard, corn stalks, fruit waste, leaves, newspaper, peanut shells, pine needles, sawdust and straw

Building and turning

The magic of muck – a compost pile gives
evidence of the heat-producing action of
bacteria breaking down organic matter

Day 1: Shred the carbon material to pieces no bigger than 5cm, about the size of your thumb, and crush them so they are as fibrous as possible. This offers more surface area for the composting process.

Saturate the pile with water as you mix the manure and the carbon materials together.Once this is done, cover it if it is rainy, to avoid too much water getting into your pile.

Day 4: Turn the pile upside down and inside out (this should take about 20 minutes). Then repeat this process every two days, adding water as necessary.

Getting the correct moisture content

This is crucial. Test this each time you turn the heap by picking up two handfuls of compost and squeezing them together. If you see water pushing to the surface, or a single drop comes out, it is fine. If no water is seen, the pile is too dry – add water as you mix. If two drops or more come out, the pile is too wet. This is a problem and will slow compost production by at least two days. To remedy this, ‘fluff’ the pile with a fork and dig a chimney-type hole through the centre to let more air in (force in an implement handle or pole and move it about to widen a little).

Getting the right temperature

By Day 8 your heap should be between 55-65º, which is too hot to keep your hand in.

If you see white powder forming in the heap, it is too hot: do not compact the heap, ‘fluff’ it to allow more air to circulate add sawdust.

If you are successful you should end up with a nice smelling, warm, dark brown compost which can be sieved and used for potting.