Survival, development and production of compost worms depend of their environment, and more specifically of six essential variables.

1. Air or Oxygen


  • Worms breath and need oxygen. They cannot survive in anaerobic conditions, e.g. a hermetically closed compost bin. For this reason, a vermicompost bin includes aeration holes. Inside the bin, the worms make galleries at the surface that help aerate.
  • Eisenia Foetida worms can hardly survive under 50 cm of depth. The content of a bin must be kept not too deep or compact. A compost bin that lacks air smells bad and the compost take a brow-yellow color.

2. Temperature



  • Ideal temperature is between 15° and 25°. Under de 5° and over 35°, the worms will stop reproducing and look for a more favorable place deeper. Under 0° and over 40°, the worms die massively. At the extreme temperatures, the ecosystem is also affected: organic waste stop decaying or the elevation of temperature may boost undesirable bacterial or insect’s activity.

3. Moisture



  • Ideally between 70% to 90%, the level a “wet sponge”. Less than 50% is dangerous dor the worms, and more than 90% can pose aeration problem (see first point) or encourage the population of certain parasites (e.g. Collembola, Acarid)


4. pH



  • Ideally between 6.5 and 8, worms can survive until 5 and 9. pH of a compost bin tend to naturally slowly reduce. pH can be adjusted with acid (e.g. coffee grounds, mosses, pine needles, grass, bread, etc) or basic food (e.g. ashes, egg shells, etc). Next section details the nutriments. Generally, a low pH is better than a high one, as basic pH tend to break ammoniac equilibrium of the environment. A too basic pH can generate bad smells and hurt the worms.


5. Light



  • Worms doesn’t like light. Light may not be critical, but in the sun, worms rapidly die if they dry. As soon as being directly led, they will try to hide. The inside of a compost bin must by in the dark.


6. Food and Carbone/Nitrogen Ratio



  • The content of the compost bin must be balanced between carbon material C and nitrogen material N. Carbon materials are often “dry” nutriments, and include cardboard, paper, plan leaves. Nitrogen materials are often “wet” nutriment, and include vegetables and fruits. Most nitrogen materials also contain carbon but at a lower concentration. When feeding the compost bin, a high ratio of C/N must be kept, which means much more carbon than nitrogen. A good compost must have 60% of carbon material and 40% of nitrogen material. For more detail on C/N ratio (or C:N ratio) see references.