I've shared this great project on the Workshop Instagram account today as there's been so much discussion there about composting and worm farms.
Composting is an interesting process.
It naturally occurs in nature & is really better described as decomposition with compost being the outcome of the process if that makes sense.
The process of composting naturally generates heat as the various microbes go about their work decomposing the material. In a natural setting, say fallen leaves beneath trees, the heat generated would not even be noticeable and in some cases may not even be present as material may just literally rot.
In a man-made composting system there should always be heat as this is the indicator that the heap is working well and the heat is also required to kill any weed seeds present. In nature material that breaks down is likely to be from a single source, like my fallen leaf example, but in a compost heap there will be mixed material – grass clippings, kitchen scraps, garden prunings, dry leaves etc. This will sometimes simplistically be called wet & dry material or nitrogen & carbon material the aim being to keep the heap 50:50. Too wet or dry and the composting process won’t activate. To create a ‘hot’ heap you also need good airflow as this provides the oxygen the composting process requires. Hence the nice open sides on @timjeffries very nice bays.
Composting can be a very complex process, personally I think people sometimes overcomplicate it. Our grandparents managed to get pretty good compost going without the help of 400-page books from experts on the topic
Simple tips for a good, hot heap –
- don’t put your heap in full-sun or heavy shade,
- ensure good airflow,
- keep the materials you put in balanced,
- fork it over regularly,
- if it gets too dry give it a light sprinkle and fork it,
- if it gets too wet turn it over regularly to speed up the drying.
If your heap doesn’t seem to be starting well you can inoculate it by forking through a bag of good quality well-composted manure or water it with something like Seasol or another bioactive product. This will add bacteria to kick-start the process. You’ll even find there are ‘compost accelerator’ products.
And how hot can a heap get? They can actually spontaneously combust… Rare, but true story.
You might like this little vid I made a few years back now on making a compost bay system from reclaimed pallets
Not sure why I didn’t see this post originally. Sorry @Isobel.
@Adam_W has given a great explanation above.
I’d also recommend this article https://deepgreenpermaculture.com/diy-instructions/hot-compost-composting-in-18-days/
I read it when I was dreaming about having awesome soil for my garden and it’s changed my gardening life. 😊
I have to get some compost bays started here at our new place but have some issues to oversome first... the spots with the right levels of sun get way too much water when we get heavy rain so I'll need to raise the ground levels. Simple stuff like that turns a smallish project into a major one...