State University Extension
Home Maintenance And Repair - 01500589
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
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
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
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
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
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.
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).
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.
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
Compost can be mixed with topsoil for use with indoor potting plants.
Sterilize by baking in a 200-degree oven for one hour.
Backyard Composting Made Easy, Wisconsin Department of Natural
Composting.- A Solid Waste Alternative, Michigan Department of Natural
Resources, Community Assistance Division, P.0. Box 30028, Lansing, MI
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
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
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
This information comes from Michigan State University Extension
bulletin WM 02, Backyard Composting.
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status. Issued in furtherance of MSU Extension work, acts of May 8 and
June 30, 1914, in cooperation with the U.S. Department of Agriculture.
Thomas G. Coon, Director, MSU Extension, East Lansing,MI 48824. This
information is for educational purposes only. Reference to commercial
products or trade names does not imply endorsement by MSU Extension or
bias against those not mentioned.
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