Its hot, when you’re not
There is nothing quite so satisfying for me as heading outside on a frosty morning to feed the chooks, passing the compost pile and scratching the ice of the thermometer dial to reveal it is a very steamy 65 degrees in there, just under the straw.
Now, you may have heard (because it is repeated so often) that to make a hot compost pile you have to build at least a cubic metre of compost all at once and that you have to turn that pile every three (or 5 or 7) days for several months. That all sounds like too much work to me too.
YIMBY composters are trained in our ‘Continuous Hot Composting Method’, where cubic metre compost piles are built up over 5 – 7 weeks. This gives us time to collect and collate our compost materials, it means composting is a regular weekly garden task - so doesn’t become one insurmountable job - and it means there is always somewhere hot, and therefore safe, to put any kitchen and garden scraps.
The secret to continuous hot compost making lies in the balance (or mix) of ingredients and the volume of material.
For ‘Continuous Hot Composting’, balance is fundamental, and achieving this good balance of compost ingredients has been the focus of many of our ‘conversations’ over the last year. If you want a refresher, look up back-issues on the YIMBY* website: Carbon:Nitrogen ratios #13, Moisture Content - #12, Density - #30 and #31.
So, let’s look at the question of volume in more detail. We still want to end with at least a cubic metre of material in our finished pile, but instead of building this in one big day of work, we are going to break this into 5 – 7 more manageable chunks. Each week, our composting task is to add around 140 litres to 200 litres of balanced composting material to our compost pile.
From week one (if we have that balance right) the pile will start to heat up and achieve temperatures of 55o+. It will look like we are adding a quarter to a third of our bay each week, but as it heats and decomposition gets active, it reduces in size.
Each week as we add to the pile, it will get hot in that upper, active compost zone. After 5 – 7 weeks, when the cubic metre bay is (very) full we leave it to get hot and stay hot for at least 3 days, or up to a week. After this the pile is ready for its first of only two turns.
We’ll cover the details of our hot compost turning technique in another article, but you have above the basic composting technique that is making so many YIMBY compost piles hot every week of the year, regardless of the weather.
AUTHOR: JOEL MEADOWS
Joel Meadows works with *Yes In My Back Yard, (YIMBY), a community-scale composting initiative in Castlemaine and surrounds. Send questions or comments to hello@yimbycompost.com or to book in for a compost workshop!
This was also published in the Midland Express on 21 August 2024