There is an array of different composting systems that we can use at the home garden or municipal council level to speed up the decomposition process to produce the 'black gold' that is compost for our soils. Some composting processes are faster than others, but the most important thing is to choose a composting method that is practical for your individual situation rather than necessarily trying to go for a system that may well be the fastest, but is not necessarily achievable in your situation because you may not have the time, space or volume of materials available to you. Far better to do your research and choose a sustainable and achievable outcome that will work for you and the environment every day of the year.
Let's look firstly at the 'Formula 1 Ferrari' system that is the absolute fastest, namely a 'hot' composting system that relies on specific bacteria and fungi that thrive in temperatures up to 75 degrees Celsius, resulting in the whole process being usually completed in a matter of weeks. Such systems are used at the large scale municipal composting facilities where local council green waste collections end up. Organic materials are put through huge grinding machines to reduce the particle size, particularly of woody materials, which in turn helps the composting organisms to digest things more quickly. Large windrows of organic materials are blended with the optimum balance of nutrients and kept moist and turned every few days to ensure every part of the piles are subjected to high temperatures to not only speed the process dramatically, but also to kill weeds and and plant diseases that may be harbouring in the ingredients being used to make the compost. A hot compost heap is achievable at the home garden level if you have several conditions. Firstly, you need at least a cubic metre of organics at the time of making the heap. Secondly, the ingredients need to be alternating layers of a balance of about 75% high carbon 'browns' such as aged woody garden clippings, dead leaves and cardboard, and 25% high nutrient 'greens' such as fresh lawn clippings, kitchen scraps and animal manures of all sorts. Thirdly, the heap needs to be turned at least once a week until it is fully composted.
The alternative if you don't have the conditions to make it hot, is a cold composting system. This can be either a worm farm or a compost heap or bin where it never heats up to any significant degree and relies on organisms that thrive in cooler conditions, but the process takes longer for complete decomposition to occur. Having said that, worm farms that are working at peak efficiency can process organics such as kitchen scraps at a rate that can usually keep up with the output of most families. A cold compost heap is one where all manner of household organics such as garden prunings, lawn clippings, hair, shredded paper, cardboard and kitchen scraps can slowly decompose over a period of months (it will take longer during the winter period). If your cold compost heap is in contact with the soil (which we would recommend), you will usually get native earthworms coming from the soil into your heap, speeding up the process, or you can add compost earthworms from a worm farm if that is available to you. the disadvantages of cold compost heaps are that they do not kill many weeds such as lawn grasses with runners such as kikuyu and couch, or plant diseases that may be present on prunings from your garden. These organics are best left to council pick ups where they will go into hot compost systems mentioned earlier. Cold compost heaps and worm farms can also be invaded by mice and rats so it is important to use a system that prevents their entry. A Tumbleweed Gedye Bin is a solid plastic bin with a snap on lid, and if you create a fine mesh base for it you can stop rats and mice digging underneath to gain entry.
Worm farming is a fascinating variation of cold composting where we create perfect conditions for special 'composting' earthworms that have been bred for their ability to process concentrated organics such as kitchen scraps very efficiently. The two species most commonly used are red and tiger worms. There are a few important points to being successful with worm farming. You should add relatively small amounts of organics often to stop things from heating up. Burying the newly added material under the surface gives the earthworms an immediate advantage of not having to come to the surface where they compete with other organisms. Also use a covering such as an old towel or Tumbleweed Worm Blanket to provide the darkness the worms thrive in. Do not over feed your worms which you will be able to tell by things getting smelly or if there is lots of mould growing in the worm farm. If you feed a little and often the worm population will build over time and when you find a writhing mass of worms when you dig down, you will know that your worm farm is at peak efficiency and you will probably be surprised at how quickly it can process your kitchen organics. It is also very important to also add a balance of 'brown' high carbon materials such as shredded cardboard or woody materials such as dead leaves and small twigs to open things out a bit to provide the oxygen the worms also need.
Bokashi composting is a third cold composting technique that is particularly useful in small urban spaces such as home units and flats. It is an ancient Japanese technique that utilises a fermentation process not unlike that used to preserve fruit and vegetables by pickling them. Bokashi bins and buckets have snap on lids to limit the amount of gas exchange to maintain a low oxygen environment that favours the specialised microbes that are added regularly, preferably whenever you make a deposit of organics into the system. The end result of Bokashi composting is a rich liquid that is tapped off and diluted to be used as a liquid fertiliser for your indoor plants or garden, as well as the fermented semi-decomposed residue that is then either buried in a compost heap, worm farm or hole in the ground where the decomposition process is very rapidly completed in a matter of a week or two.
In summary, there is a multitude of different composting systems that can be employed at any scale to help not only keep organics out of landfill where they create endless problems, but also we can compost locally to put priceless nutrients and carbon back into our soils where they belong and can be used to grow herbs, fruits and vegetables to provide super healthy organic produce to keep ourselves healthy and fighting fit. Happy composting!