What’s Happening Inside The Pile?

There are many different types of compost piles.
For hot composting, there are 3 main phases:
Mesophilic (moderate temperature), lasting for a couple of days
Temperature reaches up to 90 degrees Fahrenheit and beyond. There is rapid growth of Mesophilic bacteria and fungi, that breakdown soluble sugars and starches, causing the temperature to rise.
Thermophilic (high temperature), a few weeks
As temperatures increase well beyond 120 degrees F, Thermophilic bacteria, actinomycetes, and heat-tolerant fungi populate the pile. They break down proteins, fats, hemicellulose and cellulose. Eventually, the organisms begin to run out of food, and so the temperature of the compost pile drops.
Mesophilic Curing, several months
Temperatures drop back down below 140 degrees F, allowing Mesophilic actinomycetes, bacteria, and fungi to enter the pile. Over this several month period, the microorganisms break down lignin and other highly resistant compounds.

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