Beginning with Bacteria
Microscopic in size, bacteria are the most numerous organisms in the compost pile. They are on all natural matter in
the heap and reproduce at an amazing rate under the proper conditions. Their work initiates the activity of a succession of various organisms, each of which further breaks down complex materials to be utilized by its successor.
These tiny powerhouses break down organic materials by enzymatic digestion, resulting in chemical oxidation that promotes their life processes. This oxidation is what generates the heat in compost piles. Each group of microbes operates in its own temperature range, laying the foundation for the work of the next group.
There are three basic types of bacteria:
- psychrophilic--active at 0°-50 ° F.
- mesophilic--operate in 50°-100 ° F. range.
- thermophilic--optimum 100°-200 ° F. range.
Initially, these are the most active decomposers in the pile. Each has a limited active role. Psychrophilic is limited in its range. Mesophilic temperatures are where most garden composting begins. These microbes gradually give way to thermophilic bacteria as the pile gets hotter. The more thermophils in the pile, the hotter it gets. Thermophilic is active
for only 4 to 7 days unless fed new material or turned at strategic times, yet it is the most dynamic
producer of deep brown compost for soil enrichment. Thermophilic microbes also generate enough heat to kill weed seeds and diseases not wanted in gardens.
Again, bacteria do not have to be added to the pile because they are already present on all organic
matter. They reproduce by division; body cells develop a wall down the middle and become two, again and
they become four, then eight, and so on. It's a rapid process when heat, moisture and air are all present in proper quantities.
Other Composters
Credit needs to be given to other organisms larger than bacteria that play pivotal roles in the
composting drama. They quite often feed on the spent bacteria and their by-products, adding diversity
to the pile. These other contributors are:
- Actinomycetes - higher-form bacteria, often deep-soil dwellers, similar to fungi and molds;
provide nutrients for plants by liberating carbon, nitrogen and ammonia.
- Fungi - primitive plants, lacking chlorophyll, that break down organic matter to obtain energy.
- Soil invertebrates - physical decomposers, higher in the food chain, that chew and grind in the compost pile; first-, second- and third-level consumers, depending on what they eat and are eaten by.
- Springtails
- Mites
- Centipedes
- Sow bugs
- Beetles
- Wolf spiders
- Redworms
Each has a unique contribution to the joie dê vïvre in the pile and interacts most efficiently
in the special ecosphere of the heap. They are all beneficial inhabitants.
Composting for Life |
Growing Microorganisms |
The Five Laws |
Building the Pile |
The Finished Product |
Page 3