Published on 03 February 2025
This week we caught up with Matthew Daniel from the Hepburn Shire Council (Council) Parks and Gardens team to see how our compost trial is progressing.
In the picture to the right is 40 cubic metres of compost made from kerbside food and garden organics from our townships across the Shire. The volume of compost produced is less than the volume of material collected because, just like spinach, organic matter dramatically reduces as it ‘cooks’.
The first stage of composting occurs in our rapid in-vessel composting units at Creswick Transfer Station. After two weeks, the compost is taken out of the vessels and allowed to cool outdoors while it continues to mature and gets closer to being ready to be applied to plants. Matthew explained that much like the story Goldilocks and the Three Bears, good compost needs to not be too hot, too cold, too wet or too dry. He has been closely monitoring the temperature and moisture of the maturing compost so we know when it will be ready to use.
Recently, the compost was 40 degrees which is an indicator that it is almost ready to use on sites. The temperature of the compost tells us how active the thermophilic (heat loving) bacteria are. Now that the temperature is decreasing, we know that the bacteria activity is slowing. Once it reaches an ambient temperature, the compost is considered ‘optimised’ (has the right mix of microbes) and is ready to apply to plants.
Optimised compost helps to prevent disease but also improves the structure of soil to reduce compaction and increase water retention, a bit like a vaccine does for humans. Matthew will also test this compost to see the microscopic organisms (like bacteria, microbes, fungi, protozoa) present, before putting it to use.
Matthew also showed us the compost tea making kit he is putting together. Soon he will be adding small amounts of compost to ‘brew’ up a microbe rich tea that can be sprayed around the base of trees to improve their health.
Council staff are working hard to remove contamination at various stages, mainly by hand. However, it is very difficult to remove completely, so we are still seeing some contamination (for example, plastic) ending up in the compost pile. By far the easiest way to keep our compost clean is for residents to avoid putting any plastic (such as bags) or other rubbish in the lime-green bins. Visit our Food and garden organics webpage to find out what you can and cannot put in your kitchen caddy and lime-green lidded bins.
Soon, we will be ready to start applying this first batch of compost to our Parks and Open Spaces trial sites to measure the benefits as part of the Sustainability Victoria funded trial. For more information on this project, visit Council’s YouTube channel.