|Latest Update 5th March 2017.|
You don't need a formal structure like the one above to make thermal compost, but this one has been designed to make relatively small batches with less effort.
Go to my page "How to Build a Hot Compost Bin" for more information.
|The organic waste in the photo shows a batch of compost after the initial period in the enclosure. The enclosure has been split and is ready to be dragged to a new location for reassembly.|
|The 2 halves are clipped together using cabin hooks to make a new enclosure. The compost heap is broken up and transferred into the enclosure tossing the materials into the air to mix and aerate them.|
|Water is sprayed onto the materials as the compost bin is being filled. The compost must remain moist at all times, but not soaking wet (about 75% saturation).|
|Although the compost settles a little during the first period, aerating it has restored its volume.|
waste used in a compost heap is any material which was once alive and
growing, and for the purposes of hot composting, is made up of nitrogen
and carbon rich wastes. Soft green plant
material and animal manures have a high nitrogen content and brown, dry and woody
organic material, like straw or autumn leaves have a high carbon content.
In theory, the ideal conditions for thermophilic microbes to multiply is when there is 30 times as much carbon in the mix as nitrogen, the temperature is between 55C and 65C, and the moisture content is about 75%. For proportions of carbon and nitrogen in different types of organic waste take a look at Deep Green Permaculture's chart in their blog Hot Compost-Composting in 18 days.
For the amateur organic gardener, this is unnecessary detail in my opinion and you can get by quite well with a simpler formula of twice as much carbon rich waste as nitrogen rich waste. Experience will help you get the ratio right first time if your source of materials is reasonably consistent. For my compost heap I harvest grass clippings, vegetable garden waste, kitchen waste, and prunings from trees and shrubs. The material is a mixture of carbon and nitrogen to begin with, and I only need to add used straw mulch to increase the carbon content to reach an ideal level.
Its important when gathering organic waste for a compost heap, to keep the nitrogen rich and carbon rich components separated, and its also important to keep them as dry as possible so they don't start to decompose anaerobically.