We built the pile one layer at a time, like a huge sandwich: Alternating dry material with green material, then a layer of soil. Another way to look at it is layering nitrogen-rich material with carbon-dense matter and then another layer of soil and or compost. We made the pile large enough to create an insular mass for the microbes to thrive. In the tropics 3 foot by 3 foot by 3 foot works. In temperate climates increase that to four-foot all around.
After lunch we came inside to review the soil food web and the basics of making compost.
If you explore a forest floor below the leaf litter, you find humus, the result of an entire soil food web. Compost is a way to speed up the process by providing the decomposers—soil bacteria, fungi and invertebrates with all the nutrients they need. We work with microbes when we make bread, yogurt, or sauerkraut. Compost is messier and larger but is similar in that we are creating an environment for microbes to thrive and directing their behavior to produce a product we want.
The building blocks of compost are nitrogen-rich material for strong bodies, carbon-rich material for organisms to energetically reproduce, air so the pile stays aerobic and doesn’t go putrid, water to hydrate to microbes, and soil or aged compost to inoculate the pile with organisms.
Compost enhances the garden in so many ways:
- It reintroduces soil microbes to soils that have been damaged by chemical fertilizer and pesticides.
- It improves the soil ecosystem and encourages beneficial microorganisms that protect plants from pathogens while soil fungi bind with and filter out toxins.
- Compost prevents soil erosion by improving soil structure. Soil rich in organic matter is more porous; it allows air and water to move and be held, it has good tilth.
- “Feed the soil and the soil feeds the plants,” is a famous Alan Chadwick quote I learned years ago. Compost feeds soil microbes that in turn release enzymes and hormones that promote healthy plant growth. Decomposing organic matter releases nutrients. The dead bodies of microbes act as slow-release fertilizer, providing nutrients over time.