Making Compost from Yard Waste
Contact: Diane Relf, Extension Specialist, Environmental Horticulture, Virginia
Tech
Publication Number 426-703; Revised 2001
Table of Contents
What Is Compost?
The Compost Bin
Keys to Good Composting
Making Compost
Compost All Your Yard Wastes
Benefits of Composting
Why Make Compost?
What Is Compost?
Compost is one of the most valuable resources for beautifying your landscape,
and it is virtually free. The leaves you rake, the grass you mow, and the
branches you trim are some of the ingredients you can use to make compost.
Finished compost is dark and has a pleasant smell. It is produced when organic
matter, such as garden, lawn, and kitchen waste, is broken down by bacteria and
fungi.
Use it throughout your landscape - till it into gardens and flower beds, add
it to the soil when renovating your lawn, Or sieve it and use it in potting
soil.
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The Compost Bin
A compost pile can be as plain or fancy as you want - you don't even need a bin
to make compost. But if you plan to produce compost regularly, consider a
permanent compost bin. For convenience and aesthetics, you can choose from
numerous commercial composters or construct your own from wooden planks,
concrete blocks, used freight pallets, hardware cloth, or chicken-wire.
Before purchasing a commercial composter,
determine if it will work effectively in your landscape. It should be well
built, economical according to your needs, easy to assemble, and have easy
access for turning the compost. It should also be large enough to handle all the
leaves in your yard.
Some gardeners build separate bins for each stage of the compost process -
one for fresh plant refuse, 'another for the actively composting pile, and a
third for the finished compost. When building your own bin, keep one side open
for easy access. Also, leave spaces between blocks or planks for aeration - air
is essential to the rapid decay of organic materials.
The size of the compost pile determines how effective it will be; piles
smaller than 27 cubic feet (3 X 3 X 3) do not hold sufficient heat for the
composting to be effective, and piles larger than 125 cubic feet (5 X 5 X 5) do
not allow sufficient oxygen to reach the center. Be sure your compost pile is a
manageable size.
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Keys to Good Composting
- The carbon/nitrogen ratio: A mixture of dry leaves, sawdust, or other
sources of carbon combined with manure, green plants, or fertilizer for
nitrogen (approximately 4:1 by volume).
- The presence of microorganisms: A few shovels full of rich garden soil or
compost will supply these.
- The moisture level: The pile should have the moisture of a well-squeezed
sponge. Add water as needed.
- The oxygen level: A compost pile should be turned periodically to promote
decay of its contents. Turning the pile adds oxygen, so the more you turn it,
the faster it breaks down. (Turning heavy, rotting leaves and grass is
vigorous exercise!)
- The particle size: The finer the particle size, the more surface there is
for microorganisms to work. Shredding leaves and larger materials generates
compost faster.
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Making Compost
Locate your compost pile on a well-drained site which would benefit from
nutrients running off the pile. Your pile can be built gradually in layers and
then turned to mix. Or if you have sufficient material, it can be mixed and
blended at one time.
- To ensure good aeration and drainage, put down a 3-inch layer of coarse
plant material, such as small twigs or chopped corn stalks, or a wooden
pallet.
- Next, add about 8 to 10 inches of leaves or other dry organic wastes from
your landscape and/or kitchen.
- Provide nitrogen for compost-promoting microorganisms by adding 2 to 3
inches of fresh grass clippings or fresh manure. If fresh nitrogen sources are
unavailable, add about one-third cup synthetic fertilizer (36-0-0) per 25
square feet of surface area.
- If no soil is included in your compost material, add a sprinkling of soil
or a compost starter to each layer to inoculate the pile with microorganisms.
- Moisten the pile as you add leaves and other dry material.
Mix the materials thoroughly. Shape the pile so its center is lower than its
sides, to help water flow into the pile. Keep the pile moist, but not soaking
wet. Within a few days, it should heat up. If not, it may lack nitrogen or
moisture. If the pile emits an ammonia smell, it is too wet or too tightly
packed for oxygen circulation; turn the heap and add coarse material to increase
air space. Once a month, turn the pile with a pitch fork, putting the outside
materials on the inside and vice versa.
The plant materials should decompose into compost within five months in warm
weather, longer under cool or dry conditions. The center of the pile should
reach 160öF. to kill most weed seed, insects and eggs, and disease organisms.
Composting may be completed in one or two months if the materials are shredded,
kept moist, and turned several times to provide good aeration. Spread it in the
garden and dig or till it under to offer your soil and plants renewed vigor.
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Compost All Your Yard Wastes
Grass clippings and fall leaves are abundant compost materials for most
homeowners. Weeds free of seedheads and crop residues, such as vines and leaves,
are other sources. Never include weed seed or perennial roots or stems that
might become established. Collect vegetable and fruit peelings, coffee grounds,
crushed eggshells, and similar kitchen waste for your compost pile. Don't use
meat waste; it attracts animals. Acquire additional materials, such as sawdust,
manure, hay, or straw, from sources such as stables and carpenter shops.
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Benefits of Composting
- Compost improves the structure of soil. With the addition of compost,
sandy soils hold water better, and clay soils drain faster.
- Compost reduces soil erosion and water run-off. Plant roots penetrate
compost-rich soil easier and hold the soil in place. Water can run down into
lower soil layers, rather than puddle on top of the ground and run off.
- Compost provides food for earthworms, soil insects, and beneficial
microorganisms.
- Compost assists the soil in holding nutrients, thus lessening the need for
chemical fertilizers and preventing the leaching of nitrogen into water.
- Compost promotes healthy plants which are less susceptible to diseases and
insect pests, reducing the need for pesticides.
- Composting in your backyard recycles wastes which might otherwise fill up
landfills. Leaves, grass, and debris - often raked into the street for
collection - tend to clog storm drains and street gutters and are costly to
collect, but make excellent compost materials.
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Why Make Compost?
Virginia is rapidly running out of landfill space. Consequently, we must make
our old landfills last longer. One way to do this is to compost yard and kitchen
wastes, which comprise an estimated 20 percent of the refuse going into our
landfills. Homeowners who compost not only extend the lives of our landfills,
but also reduce costs for collecting organic debris. Also, composting recycles
waste to create valuable soil amendment.
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For more information on selection, planting, cultural practices, and
environmental quality, contact your local Virginia Cooperative Extension Office.
If you want to learn more about horticulture through training and volunteer
work, ask your Extension agent about becoming an Extension Master Gardener. For
monthly gardening information, subscribe to The Virginia Gardener Newsletter by
sending your name and address and a check for $5.00 made out to "Treasurer, Va.
Tech" to The Virginia Gardener, Department of Horticulture, Virginia Tech,
Blacksburg, VA 24061-0349. Horticultural information is also now available on
the Internet by connecting with Virginia Cooperative Extension's server at
http://www.ext.vt.edu
The original development of this series was funded by ESUSDA Smith Lever 3(d)
National Water Quality Initiative Funds and the Virginia Department of
Conservation and Recreation, Division of Soil and Water Conservation.
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