Composters use several strategies to maintain airflow. The most
basic one is to blend an assortment of components so that coarse,
stiff materials maintain a loose texture while soft, flexible stuff
tends to partially fill in the spaces. However, even if the heap
starts out fluffy enough to permit adequate airflow, as the
materials decompose they soften and tend to slump together into an
airless mass.

Periodically turning the pile, tearing it apart with a fork and
restacking it, will reestablish a looser texture and temporarily
recharge the pore spaces with fresh air. Since the outer surfaces of
a compost pile do not get hot, tend to completely dry out, and fail
to decompose, turning the pile also rotates the unrotted skin to the
core and then insulates it with more-decomposed material taken from
the center of the original pile. A heap that has cooled because it
has gone anaerobic can be quickly remedied by turning.

Piles can also be constructed with a base layer of fine sticks,
smaller tree prunings, and dry brushy material. This porous base
tends to enhance the inflow of air from beneath the pile. One
powerful aeration technique is to build the pile atop a low platform
made of slats or strong hardware cloth.

Larger piles can have air channels built into them much as light
wells and courtyards illuminate inner rooms of tall buildings. As
the pile is being constructed, vertical heavy wooden fence posts, 4
x 4's, or large-diameter plastic pipes with numerous quarter-inch
holes drilled in them are spaced every three or four feet. Once the
pile has been formed and begins to heat, the wooden posts are