Updated: Oct 12, 2020
I feel a little embarrassed to say, but this was my first time creating a hot compost. Every time I learn something new I have to take off my “experienced adult” hat and put on my “curious learner” hat, which reminds me of sitting on the mat at primary school. I try not to get frustrated at my lack of knowledge and instead embody the mentality I had a primary school. Here’s my understanding of what we learnt, which is likely inaccurate in places.
Dave is an experienced permaculturalist and invited my friend, Kat, and me to begin the compost 101 learning experience by discussing compost theory. He began by asking us “what do plants need to be healthy?” We got there in the end - sun, H20, nutrients, air, pollinators, insects, biology (micro-organisms), and minerals. We then started to talk about the different organisms in soil - worms, insects, bacteria, fungi, protozoa, nematodes, algae, and many more. I started to imagine the biggest bugs, like worms, being able to eat the processed material from smaller bugs. And even smaller bugs providing for the next size up and so on. We later found out that fungi prefer a compost with more carbon and bacteria prefer a compost with more nitrogen. Trees prefer soil with more fungi and vegetables prefer a soil with more bacteria.
Dave then asked us what compost is? I talked about it being a potion and an environment for plants and biology, but Kat really hit the nail in the head when she said: “it’s part of the cycle”. We’re not really creating food for plants; the compost is alive and it is made from organisms eating the plant matter and providing nutrients from their poo and carcasses for the plants that we’re growing. What we’re creating is food for the soil as a whole to flourish. Commercial farming primarily adds chemical fertilisers, which kills the life in the soil and it basically becomes a dead medium reliant on chemicals coming from a process that is anything but good for the planet.
We then talked about the different layers of the compost. About 70% is carbon (browns), which is mostly made up of dead plants. This is carbon that has been absorbed from the atmosphere, which we’re putting it back into the soil. So cool! Then there is Nitrogen (greens), which comes from “alive-ish” plants or food scraps. There are also additives and activators, designed to speed up the composting process, which is already full of micro-organisms. In our case, we had sheep poo mixed with water and a tea made from comfrey, nettle, seaweed, and a product called Essential Micro-organism. We also added minerals from a product called Bio-phos and more organisms from a dead rabbit and some fish that had gone off.
The main difference between a cold compost and a hot compost is the amount of material that is combined at any one time, which intensifies the chemical reaction. It requires at least 1m by 1m of material to produce enough heat for a hot compost process, which is essentially faster at breaking down into the soil. Cold compost is more typical of household compost heaps. It still gets hot but composts much slower. A hot compost gets to about 70 degrees and when the heat comes down, you turn it and the heat goes back up to 70 degrees again. You keep doing this until it’s broken down into a nice looking soil.
I felt like I was learning a lot in this theory session, but once we started to gradually form the compost heap by layering carbon, nitrogen, additives and activators, again and again, the new learning started to compost in my mind and solidify. The key is time to reflect and the experience of doing it - seeing it, smelling it, feeling it. I felt tyred by the time we were finishing, but a beautiful golden light was shining and I could sense my wellbeing increasing.