May 2016 (2)

Its the end of autumn in Melbourne, and its been unusually mild.  I've been busy tree lopping and cleaning up autumn leaves etc and the chipper has been reducing course materials to a state suitable for thermal composting.

Its essential to reduce the size of the material used in a compost like this so that the microorganisms can get to work right inside the material as quickly as possible.

Here is day one of a new pile, where a mixture of green waste (nitrogen rich) and brown waste (carbon rich) are mixed together.  Its not quite the full cubic metre recommended for thermal composting, but I find I can get away with it if I keep it insulated with reflective tarpaulins.  I also cover the outside initially with fresh organic sugar cane straw for extra insulation. 

Here's the heap on day 3.  There are 8 layers of tarpaulin keeping the heat in.  Its already shrunk a little as the material begins to break down.

I dig it out into 2 piles for the first time on day 4.  The pile on the left is from the outside of the heap, and the one on the right is from the hot interior.  When I throw it back into the compost bin, I put the lighter coloured material back into the middle of the heap surrounded by the hot material from the right hand pile.  

Beneficial bacteria grow at a fantastic rate in this process and heat the pile up to about 65 deg C in the centre.  To maintain this heat for a couple of weeks its necessary to aerate the heap every 2 days by moving it out of the bin and back in again inverting it at the same time.

Inverting ensures all parts of the heap are exposed to this high temperature to quickly break down the organic waste materials and kill off unwanted weeds and microbial pests.  More on my page about thermal composting.