It is a common misconception that a compost pile heats up because of the sun. Sure, if it is hot outside, the pile will be warmer than if it is cold outside, but the sun is not what causes a compost pile to hit the triple digits.
The microorganisms residing inside of the compost pile are what cause the increase in
- Psychrophiles arrive during the first stage of decomposition. They exist in the pile mainly between 55-70 degrees Fahrenheit (F). The psychrophiles start to digest the material and release carbon dioxide, water and heat. This heat causes the pile’s temperature rise whichattracts the mesophiles.
- Mesophiles thrive between 70 and 90 degrees F. The majority of the decomposition in your pile is performed by these microorganisms.
- Thermophiles will be found in your compost pile when the temperature rises above 104 degrees F. These temperatures will kill off almost all harmful organisms and weed seeds that may reside in your pile.
If a compost pile rises in temperature, it is an indication that the composting process is going well. When the thermophiles run out of things to eat, the temperature will steadily drop. This is a good time to turn your bin, add water, and add more nitrogen-rich green material into the center of your pile. The addition of material that is nitrogen rich, like coffee, manure, or fresh cut grass, will heat your pile right back up as the thermophiles go to work.
Compost thermometers are great ways to tell which stage of decomposition your compost pile is at. These can be purchased at the Solana Center for $20.