Composting
Composting of yard wastes such as leaves, grass
clippings, dead garden plants and hedge trimmings, along
with kitchen scraps, is popular with home gardeners who
long ago discovered the benefits of the dark, rich,
sweet-smelling, earthy end product called humus.
Benefits of composting
In about as much time as it takes to burn or bag yard
debris for disposal, you can prepare these same materials
for composting and use them as a soil conditioner. Home
composters can use humus to lighten heavy, clay soils
or enrich sandy soils to improve water-holding capacity.
Plants grow well in well-drained soils that hold some
moisture and the result should be a healthy, vigorous
garden.
Understanding and assisting the compost process
Heaping organic materials into a pile generates heat
through the activity of the microorganisms. This heat
encourages activity of other microorganisms which speeds
up the composting process. High temperatures also help
destroy weed seeds and disease organisms.
Before piling, shred or chop yard debris to give
organisms a larger surface area to decompose.
Because nitrogen is consumed by tiny decomposers, the
addition of nitrogen fertilizer or manure assists in rapid
and thorough decomposition. A proper ratio of carbon to
nitrogen is also important to the composting process.
While table scraps have a 15:1 carbon to nitrogen ratio,
fallen leaves are more in the range of 60:1. Grass
clippings have a 20:1 carbon to nitrogen ratio. A C:N
ratio of 30:1 is ideal for microbial activity, although a
50:1 ratio is adequate for a slower compost. A complete
mixing of a variety of materials will provide the desired
ratio.
Frequent turning of the compost pile also speeds up
the decay process by providing a supply of oxygen.
Building your compost pile
Backyard composting is appropriate for all
lifestyles, because it can be done on a small, medium or
large scale, using a low, medium or high effort.
Soil incorporation is perhaps the easiest way to
compost in the backyard, when space is limited and yard
wastes are minimal. Kitchen scraps, minus meat, bones and
fatty foods, can be incorporated directly into the garden.
Bury scraps at least six to eight inches beneath the
surface.
Mulching is another simple way of utilizing organic
materials. Simply spread leaves, grass clippings or
shredded woody wastes beneath ornamental plantings for
initial use as mulch, and later, as they decompose, as a
soil enrichment. Chippers or shredders can be rented or
purchased and used to chip materials for these purposes
or for informal garden paths.
Turning and holding units can be built to help
contain backyard compost piles. For yard wastes, a three-
foot square holding bin made of wire provides the
simplest method of composting. Place the bin in a
shady place and gradually deposit weeds, grass clippings,
leaves and harvest remains as they are collected.
Remember to layer plant materials and if desired, add a
handful of nitrogen fertilizer between each four-inch
layer to achieve the proper carbon:nitrogen ratio.
Layering with topsoil adds additional decomposers to the
heap.
Moisture and aeration are essential. Keep the pile
damp but not soaking. This produces a usable compost in
six months to two years, depending on the mixture of
materials. Occasional turning, shredding of materials and
addition of high-nitrogen materials or fertilizer will
speed the process.
Gardeners with large volumes of yard wastes may want
to build a series of two or three turning units or bins.
(Vis. 2) The compost can be turned and moved to an
adjacent bin on a regular schedule. Bins can be built of
wood, a combination of wood and wire, or concrete blocks.
Begin the compost pile by alternating layers of organic
materials. Monitor the moisture of the pile and check the
pile temperature regularly. The pile will heat up to
between 130 and 160 degrees in the middle, and the
outside will be warm to the touch. During this period of
intense activity, be sure the pile does not become dry.
When the pile begins to cool, turn the pile into an
adjacent bin with a shovel or manure fork. This mixes
uncomposted material from the outer edges of the pile
and the temperature should start rising again. After a
few days, turn the pile into the finishing bin and start
new layers of compost in the first bin. Through
persistence and a little extra effort, you can have
finished compost in a few weeks instead of a few months.
Remember, you can build simple wire bins, use wooden
pallets, or build more complex turning units. Depending
on your time commitment and quantity of materials, you
can select the compost method that works best for you.
(Vis. 1)
Household garbage can be easily composted by building
a worm box in your basement or backyard. Prepare a 3' by
2' by 1' wooden box with a hinged cover (this size will
accommodate the kitchen wastes from a family of four to
five).
(Vis. 2) Use shredded cardboard, newspaper strips,
animal manure, partially decomposed leaves or peat moss as
a bedding material.
Add one to two pounds of red worms (can be purchased
or obtained from manure piles). Bedding material helps
the worms escape when compost gets too hot. Household
garbage such as lettuce and cabbage leaves, carrot tops,
potato peels, citrus rinds, coffee grounds, eggshells and
moldy left-overs can be fed to the worms. Bury the
garbage in the bedding and cover it with more bedding and
let the worms go to work. Two pounds of worms can process
a pound of garbage a day. Keep the bedding damp but not
soaking. In several months you will have to move the
vermicompost (worm castings, uneaten garbage, bedding)
and worms to one side of the box. Begin placing fresh
garbage and bedding on the other side and the worms will
leave the finished compost, which can then be used as a
potting soil supplement.
Neighborhood Composting
Community garden projects are ideal for apartment
dwellers and homeowners with small backyards. Participants
can get rid of kitchen wastes harvest remains and yard
debris at the garden site. Kitchen wastes can be
incorporated directly into the soil and neighbors can join
together to develop active compost piles.
Uses of Finished Compost
Compost contains some nutrients, but its greatest
benefit is in improving soil characteristics. If you've
added fertilizer or manure during the composting process,
however, you may find the compost is all you need to
achieve good plant growth and production.
To use compost for lawns, screen the material and use
a seed-starting material or as a top-dressing.
When working the compost into the soil of flower beds
or the vegetable garden, (before or after planting) apply
at a depth of two-to-three inches.
Compost can be mixed with topsoil for use with indoor
potting plants. Sterilize by baking in a 200-degree oven
for one hour.
References
Backyard Composting Made Easy, Wisconsin Department of
Natural Resources.
Composting.- A Solid Waste Alternative, Michigan
Department of Natural Resources, Community Assistance
Division, P.0. Box 30028, Lansing, MI 48909.
Composting.: A Study of the Process and its Principles,
Rodale Press, Emmau, PA, 1977, Golueke, Clarence G.,
author.
Composting Your Garbage with Worms, Kalamazoo Nature
Center, Inc.
Guide to Composting, City of San Jose Parks and
Recreation Department.
Home Composting, the Community Composting Education
Program, Seattle Engineering Department and the Seattle
Tilth Association.
Making and Using Compost, fact sheet from the U.S.
Department of Agriculture. Office of Communication,
Washington, D.C. 20250.
The Rodale Guide to Composting, Rodale Press, Emmaus, PA,
l979, Minnich, J. and M. Hunt, authors.
Compost Do's and Don'ts
Don't use unfinished compost. It will rob your
plant's nitrogen instead of acting as a fertilizer. You
can also spread garden diseases with unfinished compost.
Do mix finished compost with topsoil to prepare
garden flower beds or for potting mixtures.
Do mix manure (if available) or high nitrogen
fertilize with yard wastes. Sprinklings of fish
fertilizer, ammonium sulfate (20 percent nitrogen) or
urea (45 percent nitrogen) also work well.
Do not use more than one-fourth pound of fertilizer
per 15 square feet of compost. When composting low-
nitrogen materials such as sawdust, paper and woody
plants, increase fertilizer rates.
Do add lime, small amounts of wood ashes or crushed
eggshells to neutralize acids which may form in compost
and cause an odor problem.
Do layer materials two to six inches thick, taking
care to mix up grass clippings (they tend to compact).
Do add topsoil to layers to provide a good source of
microorganisms.
Don't compost weeds that are heavily laden with seeds
(some will not be killed during the heating process).
Don't ignore strong odors. Simply turn the pile when
odors are detected.
Don't add meat or fish scraps to the compost mixture.
They may attract animals (dogs, cats, rats, etc.) and
they do not decompose easily.
Don't add diseased vegetable plants to the pile if
compost will be used on a vegetable garden. The disease
organisms may reappear the next year.