(Materials & methods to ensure quality
Climatic conditions, particularly temperature,
wind, and rainfall influences the composting
process. The lowest temperature at which
composting might be satisfactorily done,
is not known. A slightly larger compost pile
in winter weather will reduce the heat loss
per unit volume.
Organic compost material has excellent insulating
properties. A steep temperature gradient
exits at the outer surface of compost stacks.
The difference in temperature may be several
degrees Fahrenheit per inch of material.
Composting can can occur at severe freezing
temperatures, providing snow conditions do
not interfere with turning and the snow becomes
mixed with the compost. Turning would not
have to be done quite as often as in warm
weather, because there would be a longer
temperature recovery period after each turn
when the colder exterior of the pile was
turned into the interior.
Strong winds markedly lower temperatures
on the windward side of a compost pile. Two
factors play an important role: (a) the coarseness
of the material, which affects the porosity
and dessication of the pile, and (b) the
moisture content. Unshredded or coarsely
shredded material has a greater porosity
and permits greater penetration of wind into
the pile. Consequently, more evaporation
takes place. When the material becomes too
dry, bacterial activity is inhibited. Shredding
or grinding to produce a maximum particle
size of about 2 inches provides a more homogeneous
mass that is not as easily penetrated by
winds. Thoroughly wetting the exterior of
the pile, particularly on the windward side,
will reduce wind penetration and permit the
interior high-temperature zone to extend
nearer to the surface of the pile.
In an area of strong prevailing winds, a
windbreak could be built to protect compost
piles. This should seldom be necessary, however,
since increasing the size of and wetting
the pile will control temperatures, and all
material will be exposed to high temperatures
by turning. Wind cooling and drying of compost
piles is of little significance when piles
or bins are used, since the material is protected
on all sides except the top, which wetting
To avoid problems with rain, piles can be
finished with a rounded top so that the rainwater
can run off, and adequately drained to ensure
they are not in standing water. Heavy rains
accompanied by high winds will penetrate
a pile of coarsely shredded material as much
as 12 to 15 inches on the windward side,
but the effect on large piles can be overcome
by subsequent turning.
Turning should not be done in the rain, because
the material may become waterlogged. If the
material cannot be turned on regular schedule
owing to rain, it is better to let it become
deficient in air for a short time than soaked.
Rainy weather can present more of a problem
when composting is done in pits or bins.
The top of the pit should be rounded to turn
the water, which will, however, seep along
the edges to the bottom. The bottom should
therefore be adequately drained to remove
the water and to allow a minimum of penetration
into the compost. In rainy areas, pits should
be lined with concrete, brick, or masonry,
and provided with tile drains. Or roofs could
be built over the bins or pits to protect
them from rain.
During rainy weather, shredding or grinding,
and the segregation of the materials should
be done under cover. Facilities for storing
the incoming materials for a short time should
be provided, so that stacking or piling does
not have to be done during rain.
Composting can be done satisfactorily in
relatively cold climates or in areas of considerable
rainfall with a minimum of roofed buildings.
Heavy snowfall will greatly hinder continuous
composting operations and removal of snow
from the composting piles or bins will usually
be required. Material will not become anaerobic
or create an odor nuisance during really
cold weather. Hence, if an ample composting
area is available, the material can be allowed
to stand for long periods without turning
until the weather is favorable.