What is quality compost?

One of the most frequently asked questions is also one of the more complex to answer - what is quality compost?

It can be confusing to be presented with a range of manures, composted manures, raw mulches, quality composts and mulches and other organic materials – how do you decide which is best for you? The answer to this question will depend on how the material is to be used. The ideal properties of mulch for roadside landscaping will be very different to those required for top dressing turf.

In general, quality compost should comply with the Australian Standard for Soil Conditioners and Mulches (AS4454). Always remember that quality is not just about how a compost looks or how much it costs. Look for compost products that are supplied with clear product information, including information on how they should be applied in your particular situation. The Compost Australia Leaf Mark certified composts (based on AS4454) are designed for specific applications and are supplied with standard product information sheets.

Compliance with other certification schemes, such as organic certifications (BFA and NASAA), demonstrates the processors commitment to maintaining and improving product quality. Quality composts have undergone quality controlled processing - your compost processor will be willing to take you on a tour of their composting site to show you the process, monitoring and testing that is undertaken. Please contact one of our industry development officers for assistance with interpreting the results of compost analyses.

Poorly or non-composted materials pose the risk of introducing pests and pathogens, weed seeds and may behave less predictably than material which has undergone the stabilising phase of the composting process. Non-composted manures may conceal a surprising amount of salt, contributing significant amounts to the soil with prolonged use.

Key characteristics of quality compost:

  • high levels of organic matter and nutrients
    Organic matter is vital for good soil health and adding quality compost with organic carbon to the soil helps to improve soil condition. Australian soils are generally low in organic carbon - one of the key indicators of soil fertility. Increasing organic matter (and organic carbon) by using quality compost improves soil fertility and promotes healthy plant growth. Compost also provides the soil with a range of important nutrients that are essential for plant growth.
  • free from weeds and diseases
    Weeds and diseases are the last thing you want to introduce into your environment and adding quality compost will ensure that your landscape is not at risk. Quality compost has been through a full composting process which involves pasteurisation and microbial transformation for at least 6 weeks. During this professionally managed composting process, temperatures are high enough to disable even the toughest weed seeds.  As well as being free of weeds and diseases, quality compost will have a pleasant smell.
  • it has been professionally composted and complies with the Australian Standards
    Quality compost will be produced by quality processors! The best place to look for quality compost is at compost companies that are members of Compost WA and are committed to improving industry standards and customer satisfaction. Quality processors will be happy to supply you with information and advice about using compost as well as welcoming a tour of their facilities so you can see first hand where quality compost is made.