QUESTION: How hot does a compost pile need to be?
ANSWER: The ideal temperature for a compost pile is between 141 and 155 degrees F, as this is the temperature needed to kill weed seeds, disease pathogens, unwanted pests, as well as harmful fungus and bacteria. A hot compost pile will also speed up the decomposition process significantly. After you construct your pile, it should heat up to ideal temperatures within 24 to 36 hours. Once heated, compost can stay at high temperatures for several days and even up to a week or longer.
If your compost pile isn’t heating up, it can be a sign that there is not enough moisture or too much moisture in your pile, or that there is not enough green materials in the pile. A properly maintained compost heap that heats up correctly should decompose and break down fully within about six weeks.