Unlocking the Secrets of Composting: Understanding the Phases and Science Behind It

Hello Sykesville Community Composters!!

I’d like to share with you some of the “sciencey” details about the Phases of Composting!

Under ideal conditions, composting proceeds through three major phases: 

1.      Mesophilic phase: The initial, mesophilic phase is when the decomposition is carried out under moderate temperatures by mesophilic microorganisms. The temperature rapidly rises (up to 40°C (104°F) and initiates organic matter decomposition.

2.      Thermophilic phase: As the temperature rises, a second thermophilic phase starts, in which various thermophilic bacteria carry out the decomposition under higher temperatures (50 to 60°C (122 to 140°F).) The higher temperatures accelerate the breakdown of proteins, fats, and complex carbohydrates likes cellulose and hemicellulose, the major structural molecules in plants.

3.      Maturation phase: As the supply of high-energy compounds dwindles, the temperature starts to decrease, and the mesophilic bacteria once again predominate in the maturation phase. Nitrification mainly occurs during the maturation phase of composting, when temperatures are in the mesophilic range. Hence, maturity can also be defined in terms of nitrification. A low concentration of ammonium (NH4+) and a low ammonium/nitrate (NH4+/ NO3-) ratio indicate mature compost. 

If you want to hear more about the science and details about the Composting Pilot Program, please visit our website

Thank you for your participation and interest in this program.

Sincerely,

Tainne, Girl Scout Troop 1290