On the last farm on which I worked, the wise man who ran the farm advised us to “judge a farm by its compost”. This was an ecological farm working to biological principles, aiming to harness the best of organic, conventional, bio-dynamic and regenerative techniques to grow exceptional food good for the body and the environment. Whilst it didn’t explicitly subscribe itself to permaculture, the value placed on composting aligned very much with this concept.
Permaculture is all about harnessing nature’s services and processes in order to produce healthy, environmentally friendly food. Composting can be thought of as nature’s recycling service. In any kind of organic farming, composting is an essential fertiliser on the grounds that it isn’t using a lot of the damaging, artificial fertilisers as used in conventional farming. Some of the more general benefits of composting include the fact that it can reduce landfill waste, reduced greenhouse gas emissions from landfills sites, avoids damaging waste eliminating methods such as burning (which causes air pollution), adds to the nutrition of soil, acts as a fertiliser and pesticide, creates aggregates thus improving soil structure and reducing soil erosion, neutralises soil and promotes biodiversity.
Therefore, by judging a farm by it’s compost, you are judging its ability to to harness its local resources and use its waste effectively to successfully produce organic and healthy food.
Nature can take a long time to produce humus, and composting is a way of accelerating that by recycling organic matter which in turn gives soil the biota that it needs to make humus- the end product of the soil life cycle. The more ideal the conditions you provide for them in your compost pile, the better the resulting compost and the quicker they’ll work to break down the organic matter to make it available as food for plants.
The factors influencing these conditions include:
- Soil Micro-Organisms (bacteria, fungi, microbes)
- Soil Macro-Organisms (earthworms, insects)
- Green Materials (grass, manure, food scraps)
- Brown Materials (straw, twigs, leaves)
The Green and Brown materials each serve to build upon the nitrogen and carbon (respectively) content of the compost, and it is generally advised that they should be measured in equal parts (50/50).
While on the farm, we were constructing both Hot and Cold compost piles, which are the two main techniques.
Cold compost involves gathering materials together in a pile to decompose naturally at their own rate, and the pile is often constructed using Hugelkultur techniques. This is a method that is often used for building beds that would be planted into directly, but can also be used to build a compost supply. These are long lasting, and can produce a source of nutrient rich compost for over 20 years depending on how much hard-wood was used. This method uses anaerobic processes to decompose the organic matter, which- whilst involving less work, takes a lot longer to happen.
Hot compost is a form of aerobic composting that involves turning the compost regularly in order to ensure that it is adequately aerated. Some people choose to sit the whole pile upon an old shipping pallet as well so that the compost can be aerated from below. The green and brown material is mixed and built into a pile and watered then covered with tarpaulin (we actually omitted this stage from our composting, but it still seemed to work- possibly owing to the 40 degree celcius daily heat). The idea is that heat builds up as the organic matter feeds off of the oxygen and decomposes, and every few days the compost is turned to distribute this heat and ensure that more oxygen is supplied to the interior of the pile.
This works faster and more efficiently than its anaerobic counterpart, and therefore one advantage is that it can be ready in a much shorter period of time. Another benefit is that the higher temperature tends to mean that weed seeds and plant pathogens are destroyed in the process. Adopting the permaculture principle that every element of a garden should serve multiple purposes, a Hot compost pile could even be used as part of a water-heating system. The drawback is of course that it is much more labour-intensive than conventional and Cold composting methods. However, the compost that is produced is high quality and reduces the need to rely on external inputs, and can even be sold to local farmers as an organic and environmentally benign soil fertiliser.