After completing the insulation work on the pipes, I began work on the last layers of the pile. Thermocouples were placed in the mantle at heights of 1’, 2’, and 3’, at a radius of about 48”. The ventilation pipe coils around the pile at a radius of about 54”. Between the outer core and the ventilation pipe, I continued to fill the volume with the same alternating layers of wood chips, yard waste, and used litter from the coop. The volume at a radius between 54” and 72” was filled with sawdust and wood shavings.
Melissa gets credit for naming the last layers as “mantle” and “crust.” The mantle material may have some composting action in the winter, but probably not too much. The crust material will be too cold to compost during the winter. It is mainly there to insulate the other layers. The ventilation pipe lies at the crust/mantle boundary because experience has shown that the cold temperature of the pipe stops the nearby material from composting. The air in the ventilation pipe will mostly be warmed by conduction of heat from the mantle.
