John P's Composting Tips

Two methods can be used for backyard composting:

 

Static heap composting which is the more convenient and most popular method where a heap is built up over a long period as materials become available and Thermal composting where a compost heap is built in one operation from assembled materials.

Static Compost

 

A plastic bin or a purpose built enclosure can be used.  Many organic materials that we throw away or burn -lawn clippings, leaves, vegetable scraps from the kitchen, sawdust , paper etc. can be
converted into a soil improver and fertilizer.

As this heap forms dense layers of material it will become sloppy and exclude oxygen therefore  becoming anaerobic.  This will slow the process of decomposition so it is important to turn the heap occasionally thereby aerating the heap and accelerating breakdown of materials.

An offensive smell from your compost indicates that anaerobic bacteria predominate so it is due for aeration.  The heap should have very little if any smell at all.

Try to vary materials going into the heap and avoid large quantities of anything (especially grass clippings) as these may seal the heap.  Having the heap too wet or too dry will stall decomposition.  To be able to express a few drops of moisture from a squeezed handful of compost is a good indicator of adequate moisture.

Earthworms will eventually find their way into the heap and they are to be encouraged as they help with decomposition.  Try not to harm the critters when you turn your heap.

Remember, the smaller the size of the composting material the quicker it will break down so it helps to chop up the more bulky kitchen scraps before they go into the heap.

Keep the heap covered so it wont be flooded in a deluge or dry out in very dry weather.  Carpet is good for this but don't use carpet that has been cleaned as it will contain nasty chemical residues which could kill your compost heap.

When applying the final composting material to your garden beds it will be more effective if is just spread on the top of the soil and not dug in.  Earthworms will drag the compost down into the soil.

 

Thermal Compost

 

This method requires enough materials to make a heap of at least one cubic metre and is made in one operation.  The idea is to produce a heap in which microbial action will be so intense that a temperature of 65 deg C should be reached.  This temperature will kill off most weed seeds, pathogens and anaerobic bacteria which are to be discouraged during the early life of the heap.

The compost heap material should be made up of:

30-40% green material (green grass, weeds, Lucerne hay)

50-60% brown materials (paper, straw, oaten hay, dried leaves)

5-10%  Nitrogen materials (Fresh manures, green legume plants)

 

Add these materials in regular layers about 8" deep at the same time adding water to keep the materials moist but not dripping wet.

Cover the heap to stop entry of rain.  The heap can be just left as a heap or enclosed in some material like steel netting or straw bales.

Under ideal conditions, one bacteria in this heap can grow to 5 billion in 12 hours and this will result in your heap reaching a temperature of about 60 deg C within six days.  A minimum of 55 deg C is required to kill pathogens and it must maintain this temp. for three days.  Don't go higher than 70 deg C.  Turn the heap before this happens.  It is important to regularly monitor the temperature of the heap.

The pile should be turned 3 to 5 times and should take about 10 weeks  to complete the composting process.