Which factor is a thermal requirement for composting?

• A. Oxygen
• B. Moisture
• C. Heat
• D. Carbon-Nitrogen ratio

Answer: (C)

Temperature drives the effectiveness of the composting process. Microbes generate heat as they break down organic matter, and reaching and maintaining elevated temperatures—the thermophilic range (roughly 55–65°C)—is a key thermal requirement. This heat speeds up decomposition and helps kill pathogens, making the compost safer and faster to finish. If the pile doesn’t get hot enough, decomposition slows and sanitation isn’t achieved as quickly. Oxygen, moisture, and the carbon-to-nitrogen ratio are all important for overall performance, but they influence airflow, water availability, and substrate balance rather than the thermal aspect. Therefore, heat is the factor that embodies the thermal requirement.