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Composting is the decomposition of plant
remains and other once-living materials to make an earthy,
dark, crumbly substance that is excellent for adding to
houseplants or enriching garden soil. It is the way to
recycle your yard and kitchen wastes, and is a critical step
in reducing the volume of garbage needlessly sent to
landfills for disposal. It's easy to learn how to compost.
Composting can even be done, cleanly and unobtrusively,
indoors in apartment buildings and condominiums!
Composting is not a new idea. In the natural world,
composting is what happens as leaves pile up on the forest
floor and begin to decay. Eventually, the rotting leaves are
returned to the soil, where living roots can finish the
recycling process by reclaiming the nutrients from the
decomposed leaves. Composting may be at the root of
agriculture as well. Some scientists have speculated that as
early peoples dumped food wastes in piles near their camps,
the wastes rotted and were terrific habitat for the seeds of
any food plants that sprouted there. Perhaps people began to
recognize that dump heaps were good places for food crops to
grow, and began to put seeds there intentionally.
Today, the use of composting to turn organic wastes into a
valuable resource is expanding rapidly in the United States
and in other countries, as landfill space becomes scarce and
expensive, and as people become more aware of the impacts
they have on the environment. In ten years, composting will
probably be as commonplace as recycling aluminum cans is
today, both in the backyard and on an industrial scale. Many
states in the USA have stated goals or legislative mandates
to drastically reduce the volume of waste being sent to
landfills. Utilizing yard and kitchen wastes (which make up
about 30% of the waste stream in the USA [1]) is a big part
of the plan to minimize waste overall.
You can contribute to the 'composting revolution' by
composting your own yard and kitchen wastes at home. If you
have a large yard, you might prefer the ease of composting
in a three-bin system out by the back fence. Apartment and
condominium residents can get into the act with indoor 'vermicomposting'
-- using earthworms to recycle kitchen wastes (offices can
even recycle coffee grounds and tea bags with
vermicomposting). Cities and towns can promote composting
through home composting education efforts and the collection
of yard wastes for large-scale composting. Whatever your
style of composting, there's plenty of room to get involved!
Rot Web text (c)1996 by
What to Compost
A great variety of things can be composted at home, saving
them from a one-way trip to the landfill, and turning them
into a valuable soil amendment for home use. This list
describes some of the items you may want to add to your home
compost pile. You may want to read about how to compost to
learn about the difference between 'brown' and 'green'
ingredients and the roles each plays in the composting
process. Also, see the list of what NOT to compost
The following items can be added to your compost pile:
GRASS/LAWN CLIPPINGS
Actually, it's usually easier to leave grass clippings in
the lawn, where they will decompose and benefit the soil
directly. However, they can be composted, too. Be cautious
to add grass clippings in very thin layers, or thoroughly
mix them in with other compost ingredients, as they
otherwise tend to become slimy and matted down, excluding
air from the pile. Fresh grass clippings are high in
nitrogen, making them a 'green' compost ingredient.
HAY
Farmers are often very happy to get rid of spoiled hay bales
that have been out in the rain, and will give them away or
sell them at a low price. Grass hay will probably contain a
lot of seed, which can resprout in your garden. Alfalfa hay
will compost very readily. The greener the hay, the more
nitrogen it contains. Be sure that any hay you plan to
compost is well-moistened prior to addition to the pile.
KITCHEN WASTES
Fruit and vegetable peels/rinds, tea bags, coffee grounds,
eggshells, and similar materials are great stuff to compost.
They tend to be high in nitrogen (this puts them in the
'greens' category), and are usually quite soft and moist. As
such, kitchen wastes need to be mixed in with drier/bulkier
materials to allow complete air penetration. Many people
compost their kitchen wastes in enclosed worm bins or bury
them 8" deep in the soil, to keep from attracting pests to
an outdoor compost pile (check with your local government to
see if it has regulations about this -- some forbid open
piles containing food wastes because of the pest issue).
Avoid composting meat scraps, fatty food wastes, milk
products, and bones -- these materials are very attractive
to pests.
LEAVES
If you live in an area where autumn leaves are still thrown
away as garbage, cash in on the bounty each year by
acquiring your neighbors' leaves! Generally, leaves are an
excellent compost ingredient. They can mat down and exclude
air, though, so be sure that any clumps are thoroughly
broken up, or that the leaves are only used in very thin
layers. Ash and poplar/cottonwood leaves can raise soil pH
if used in compost -- this may not be beneficial if your
soil is already alkaline, as many soils are in the West
(especially in semiarid and arid climates). Dead, dry leaves
are in the 'browns' category, while living green leaves
contain abundant nitrogen and are considered 'greens'.
MANURE
Horse, cow, sheep, and poultry manures are often available
for free from local ranches, farms, and stables. They can
burn plants if applied when fresh, so be sure they get well
composted. Manures typically contain quite a bit of nitrogen
(the fresher the manure, the more nitrogen it contains) and
are considered a 'green' ingredient. Some manures may
contain weed seeds. Fresh manures can get a compost pile to
heat up quickly, and will accelerate the decomposition of
woody materials, autumn leaves, and other 'browns'.
STRAW
Dry straw is a good material for helping to keep a compost
pile aerated, because it tends to create lots of passageways
for air to get into the pile. Be sure to wet the straw, as
it is very slow to decompose otherwise. Straw is definitely
a 'brown' and also requires mixture with 'greens' to break
down quickly. Many stables use straw as a bedding material
for horses -- straw that has undergone this treatment is
mixed in with horse manure and breaks down more quickly.
WEEDS AND OTHER GARDEN WASTES
Many types of weeds and old garden plants can be composted.
Avoid weeds that have begun to go to seed, as seeds may
survive all but the hottest compost piles. Some types of
weeds are 'pernicious weeds' and will resprout in the
compost pile -- avoid using these unless they are thoroughly
dead. Green weeds are (you guessed it) a 'green', while dead
brown weeds are a 'brown'.
WOOD CHIPS AND SAWDUST
Wood products belong in the 'browns' category, because they
are fairly low in nitrogen. Some sawdusts, especially from
broadleaved/deciduous tress, will break down quickly in an
active compost pile. Others, especially from coniferous
trees, will take longer to decay. Stir sawdust thoroughly
into the pile or use very thin layers. Coarse wood chips
will very slowly decay, and are probably better used as
mulch unless you have lots of time to wait. Be sure not to
compost chips or sawdust from any sort of chemically-treated
wood -- you could be adding toxics like arsenic to your pile
if you do.
Rot Web text (c)1996 by
What NOT to Compost
Whether because of toxins, plant or human diseases, or weed
troubles, there are some things that shouldn't be put into
compost piles. Avoid composting the following materials:
CHEMICALLY-TREATED WOOD PRODUCTS
Sawdust is often available from constructions sites,
friends, or your own building projects. If you are
considering composting sawdust, be sure of the origin of the
sawdust. Sawdust from chemically-treated wood products can
be bad stuff to compost. For example, take pressure-treated
wood (sometimes called CCA), which usually has a greenish
tint to it (I have also seen it in other colors). It
contains arsenic, a highly toxic element, as well as
chromium and copper. There is evidence to suggest that
arsenic is leached into the soil from these products when
they are used to make compost bins or raised beds, so
composting the sawdust would certainly be a mistake. You may
wish to read the 'Letters' section of Organic Gardening,
April 1994 and July/August 1992, for more information. Avoid
other chemically-treated wood products and sawdust as well,
such as wood treated with creosote or 'penta' preservative.
DISEASED PLANTS
Many plant disease organisms are killed by consistent hot
composting, but it's difficult to make sure that every speck
of the diseased material gets fully composted. It's best not
to compost diseased plant material at all, to avoid
reinfecting next year's garden.
HUMAN WASTES
Human feces can contain disease organisms that will make
people very sick. Composting human feces safely requires
that the compost pile reach high (thermophilic) temperatures
over a period of time. It isn't necessarily that difficult
to reach these temperatures in a home compost pile, but the
potential health costs of improper composting are high.
Composting of human feces should not be attempted, except by
experienced 'hot pile' composters who are well informed of
the temperatures and times required to kill pathogens, and
who are willing to take 100% responsibility for the process
and product. If you would like to learn more about
composting humanure, I recommend The Humanure Handbook,
listed in the resources section of the Rot Web.
MEAT, BONES, AND FATTY FOOD WASTES
These materials are very attractive to pests (in an urban
setting, this could mean rats...). In addition, fatty food
wastes can be very slow to break down, because the fat can
exclude the air that composting microbes need to do their
work.
PERNICIOUS WEEDS
Morning glory/bindweed, sheep sorrel, ivy, several kinds of
grasses, and some other plants can resprout from their roots
and/or stems in the compost pile. Just when you thought you
had them all chopped up, you'd actually helped them to
multiply! Don't compost these weeds unless they are
completely dead and dry (you may want to leave them in a
sunny place for a couple of weeks before composting).
Remember also that composting weeds that have gone to seed
will create weeds in next year's garden, unless a very hot
pile temperature can be maintained to kill the seeds.
PET WASTES
Dog and cat feces may carry diseases that can infect humans.
It is best NEVER to use them in compost piles. Some people
do bury them 8" deep in the soil, but ONLY in areas where
food crops are never grown.
There are a tremendous number of options for containing your
compost. Some people choose to go binless, simply building a
compost pile in a convenient spot on the ground. Others
build bins from materials such as recycled pallets, or
two-by-fours and plywood. And, of course, there are many
commercial bins on the market.
The question arises, "Which system is best?" Each system has
advantages and disadvantages that you should consider when
making your choice. However, there aren't many significant
differences in actual composting performance between the
various traditional bin systems (two exceptions might be
worm bins and drum/turning units). More important to the
success of your efforts is taking care to provide the proper
environmental conditions for composting. Choosing a type of
bin is much more a matter of asking questions such as, "How
much kitchen and yard material do I have for composting?"
and "What system best fits my preferences for neatness,
attractiveness, and convenience?" If you're agonizing over
choosing a recycled-plastic, dome-shaped detrital digester
model for $259 versus building your own setup from $199 of
lumber and hardware, you may wish to slow down before laying
out all that cash, and make sure that what you end up with
will really meet your needs. There are some very attractive
and well-engineered commercial bins out there, as well as
plans for excellent do-it-yourself models. But why not find
out about all the options? Many people, for instance, are
very fond of low-cost, attractive units built out of wooden
pallets that are free for the asking from local businesses.
One very strong recommendation that I do have is to AVOID
THE USE OF TREATED LUMBER when building a bin system.
'Pressure-treated wood' (also known as CCA), which commonly
has a green tint, contains arsenic, a highly toxic element
(it also contains toxic levels of copper and chromium).
There is evidence to suggest that arsenic will leach into
your compost if you use CCA lumber in the bin.
Unfortunately, many extension services and local governments
actually recommend using this stuff for building compost
bins. If you are contemplating using CCA wood, please take
the time to read the information in the 'Letters' section of
Organic Gardening Magazine, April 1994 and July/August 1992,
before beginning.
Possible Composting Systems:
One Bin Systems:
A one bin system is the simplest way to make a compost pile,
and is a great way to get started. If you plan to make a lot
of compost, one bin may not be enough capacity, but adding
another can be a simple matter. The basic idea of a one bin
system is to make an enclosure for your bin that is at least
three feet (or about one meter) across, although you may
also choose to use no bin at all if you don't need to keep
everything tidy. Possible construction materials include
free wooden pallets from local businesses, lumber, cinder
blocks, or even steel posts and wire fencing. Once you've
made your bin (or decided not to), you might build a pile
all at once if you have the ingredients, but it's more
likely you'll build the pile over time as you generate
compostable materials.
If you build the pile over time, the stuff on the bottom
will decompose first, since it will have been there the
longest. When there is finished compost at the bottom of the
bin, and you want to use it, simply remove the unfinished
compost from on top, take out what you need, and throw the
unfinished compost back on top. If your pile is not a
high-temperature pile, you may want to let redworms (a kind
of earthworm) help make the compost. They'll make the
process go more quickly, and can create a very high quality
finished product.
Two Bin and Three Bin Systems:
These systems consist of two or three adjacent bins, and may
be made out of the same materials as a one bin system. The
advantage of having more than one bin is that one can have a
bin for the pile being built (as ingredients are accumulated
over a period of time) and another one (or more) for a pile
already built that is in a more advanced stage of
decomposition. If you have the space for such a system, and
are generating or gathering enough materials to keep the
bins in use, this can be very convenient. When you start
using a system like this, build your pile in one of the
bins. When this bin becomes full, 'turn the pile' by
transfering it to the adjacent bin (a garden fork or similar
tool will help). This will aerate the pile and hasten
decomposition. An alternative that I have found to be very
successful is to let redworms do the turning 'in place'
(this way I save myself labor and just leave the pile in its
original bin). Whatever you choose to do, you can now begin
to build a new pile in an empty bin while the first pile
continues to decompose.
I find that a two bin system works well for me, but other
people generate more compost or like to have a bin for
storing finished compost, and therefore choose a three bin
system. In a three bin system, you might start by building a
pile in the leftmost bin. The original pile is turned into
the middle bin when it's time to begin building another
pile, aerating it to accelerate the composting process.
Another pile is then built in the leftmost bin. When that
pile is completed, the old pile (which is now in the middle)
is turned a final time into the rightmost bin for finishing,
and the just-built pile is turned into the middle bin,
making the leftmost bin available for yet another pile.
Finished compost will eventually be removed from the
rightmost bin. Get the idea?
Rotating or Tumbling Systems:
The cost of these systems can be quite high, and they are
somewhat small, but these factors are balanced out by the
speed at which drum/tumbler systems can generate finished
compost. Under ideal circumstances, compost may be finished
in three weeks in a rotating drum composter! Fill the
container partly full with a mix of greens and moistened
browns, and then give the unit a turn every day or so to
aerate the ingredients and remix them. It's important not to
pack the container full, because the ingredients won't
tumble and mix if packed in tightly.
While one batch is composting, you can accumulate the
materials for the next batch. When the first compost is
finished, you can dump in the materials you've saved to make
more. It's possible to maintain relatively high temperatures
in drum/tumbler systems even if they are small, both because
the container acts as insulation and because the constant
turning keeps the microbes aerated and active.
Sheet or Trench Composting:
This may be the ideal system for people that have garden
space who don't want to fuss with bins and piles. Simply
bury your kitchen wastes in a trench 8" deep dug in the
garden, leave the buried materials to rot for a few months,
and then plant above them. By the time you plant, the
materials will have rotted into stuff in which plant roots
will thrive. If you have copious amounts of materials to get
rid of all at once, such as autumn leaves, you might want to
spread them around the garden and rototill them into the
soil (this is best done in the late autumn, or at least 2
months in advance of planting in the area).
Commercially Available Bin Systems:
Commercially available bins are typically somewhat expensive
compared to do-it-yourself bins, but they do keep your
compost neatly enclosed and can provide an 'instant
solution' to the question of how to set up a composting
system. In performance, many of the plastic bins may help to
insulate the compost somewhat, allowing decomposition to
occur later into the cold season. However, I don't feel that
there are major advantages in the actual composting
performance of commercial bins -- they function more or less
the same as a one bin system (described above). A few brands
seem to claim that they are able to harvest some kind of
special cosmic energy or the power of the pyramids in
assisting decomposition. Nonsense. They certainly can
function just fine as compost bins, but there is no magic
involved.
Many of the companies selling plastic bins manufacture them
from recycled plastic. If you plan to get a pre-built
plastic bin, keep your eyes open for ones made from
reclaimed plastic -- support recycling and businesses that
sell recycled products!
Clean Air Gardening - http://cleanairgardening.com - Compost
bins, manual reel mowers and other environmentally friendly
lawn and garden tools. Free US ground shipping!
Worm Bin Composting:
Maintaining an enclosed bin specifically for 'vermicomposting'
is an excellent way to take care of food wastes. In fact,
such a system can even be kept indoors. With the exception
of holes for drainage and ventilation, worm bins for indoor
use are typically completely enclosed, with a lid of some
sort to cover the top. Outdoors, worms can be turned loose
in a pile in your compost bin, or contained in a worm bin
built specifically for vermicomposting.
Some municipalities, fearful of rodent pests and the
diseases they may carry, discourage or even prohibit the
composting of food wastes in open piles, recommending
enclosed worm bins instead. A sturdy outdoor worm bin is
protected from pests, and produces compost quickly during
the warm season (or year-round in mild climates).
One of the challenges of beginning a vermicompost system is
finding a source of worms. A typical earthworm from the
garden won't do. Vermicomposting requires a species that is
adapted to living in decomposing organic materials rather
than in the soil. Two species are Eisenia foetida and
Lumbricus rubellus. Also known as the redworm, manure worm,
or red wiggler, Eisenia foetida is often available at bait
shops (ask for red wigglers), but can be mail ordered less
expensively from worm farms listed in the classified ads of
Organic Gardening Magazine. Governments and organizations
that promote vermicomposting may maintain 'worm banks' as a
low-cost source of worms for the general public. Seattle
Tilth, in cooperation with Puget Consumers Co-op, has a worm
bank at a composting demonstration site in back of a PCC
grocery store.
The general idea is to provide a cool, moist bedding (some
kind of 'brown' compost ingredient such as shredded leaves
or paperboard) for the worms to live in, and then bury
kitchen wastes in the bedding. As bacteria and fungi begin
to decompose the materials, the worms graze on the bacteria
and fungi, and also break up the ingredients with their
movement through the bedding. Eventually, the worms have
ingested the ingredients and bedding, turning it all into
worm castings (feces) that are an excellent finished
compost.
Composting with worms is very easy to do, but there are a
few basics of vermicomposting that are helpful to
understand. I plan to provide a how-to guide some day.
Meanwhile, you may wish to read the vermicomposting guide
available on the World Wide Web from CITY FARMER, an
organization in British Columbia.
Composting Resource List
The resources listed below are good for learning about
composting. Often, the books are available at local
libraries. Pamphlets published by cooperative extension
agencies are often available from those agencies for minimal
or no cost, for residents of the states or regions served by
the agency. ISBN codes are included when available (ISBNs
allow bookstores to quickly place special orders for a
particular book).
Composting Info on the Internet/WWW:
• COMPOSTING NEWSGROUP/LISTSERVE: This is an open
discussion, via email, of composting topics. To receive all
of the discussion postings, send email with no subject or
signature to listproc@listproc.wsu.edu. The message of your
email should read "subscribe compost yourfirstname
yourlastname"
• CITY FARMER: An excellent source of information on
composting/gardening in urban situations. Includes a lengthy
description of vermicomposting basics.
• In British Columbia, the Greater Vancouver Regional
District has lots of good information about backyard
composting.
• There is a large composting WWW site at Cornell
University.
• Try out the vermicompost information site maintained by
Brian Paley.
• Ontario recyclers and composters will want to learn about
the activities and projects of the Recycling Council of
Ontario.
• Chris Palmarini in California has published a composting
information site on the web. Included is a WWW-based
interactive 'bulletin board' for questions and answers about
composting.
• The Spokane (Washington) Regional Solid Waste System has a
web site with information on home composting.
• The student group SORROW at the University of Michigan is
promoting composting on campus. They have written a
feasibility study on the composting of campus food wastes.
• Recycling/Composting Links from - Advanced Life Support
and Gravitational Biology at Kennedy Space Center ALS work
at KSC concerns creating a bioregenerative life support
system for long term space missions (naturally vegetarian at
the moment).
Books:
BACKYARD COMPOSTING
published by Harmonious Press, Ojai, California, 1992 (ISBN
0-9629768-0-6). This is the simplest, most easy to read
how-to guide for composting. It is short and very easy to
read, yet presents all the basics.96 pp.
THE HUMANURE HANDBOOK
by J.C. Jenkins, Jenkins Publishing (P.O. Box 607, Grove
City, PA 16127. $19.95 ppd., ISBN 0-9644258-4-X). The
composting of human manure is controversial, or even
outrageous, to many experienced composters. Joe Jenkins
takes on the composting 'establishment' with this book,
presenting a persuasive argument for why 'humanure' should
be composted, as well as citing research to support the
safety of his method. By carefully building a pile so that
it reaches high enough (thermophilic) temperatures, and by
monitoring the temperature of the pile over time, Jenkins
argues that it is possible to safely compost human manure at
home. Those with minimal experience in composting may find
this book an interesting read, as it is very easy to
understand. However, humanure composting should not be done
unless one is an experienced 'hot pile' composter who makes
an informed choice to take 100% responsibility for the
process and its product. This is an important book in that
it opens one's eyes to the loss of what should be considered
a valuable natural resource. I found the book very
interesting and helpful. Some may be offended by the
terminology used. Nevertheless, I highly recommend this
book! 198 pp.
LET IT ROT!
by Stu Campbell, Storey Communications, Inc., Pownal,
Vermont,1990 (ISBN 0-88266-635-5). This is a good general
how-to guide for composting. It's very easy to read, but
includes considerable detail for those who want to learn
more about the composting process. 152 pp.
WORMS EAT MY GARBAGE
by Mary Appelhof, Flower Press, Kalamazoo, Michigan, 1982
(ISBN 0-942256-03-4). Mary Appelhof is an expert with more
than twenty years experience using worms to compost kitchen
fruit and vegetable trimmings. Her book is the best source
of detailed information on the simple art of "vermicomposting"
kitchen wastes. Interesting reading, with cartoons,
drawings, and diagrams. 100pp.
WORMS EAT OUR GARBAGE
by Mary Appelhof, Mary Frances Fenton, and Barbara Loss
Harris, Flower Press, Kalamazoo, Michigan, 1992 (ISBN
0-942256-05-0). A resource book for teachers who want to try
vermicomposting with their students. Activities are
appropriate for grades 4 and above. 214 pp.
Pamphlets:
These booklets and pamphlets, or similar ones, may be
available from cooperative extension offices in your state.
COMPOSTING TO REDUCE THE WASTE STREAM, Northeast Regional
Agricultural Engineering Service, Ithaca, New York, 1991.
COMPOSTING YARD WASTE, Service in Action Bulletin #7.212,
Colorado State University Cooperative Extension, Fort
Collins, Colorado, 1991.
HOME COMPOSTING, Seattle Community Composting Education
Program, Seattle, Washington.
RECYCLING YARD AND GARDEN WASTE, Circular #ANR-700, Alabama
Cooperative Extension Service, Auburn University,
Alabama,1992.
Periodical:
WORM DIGEST, P.O. Box 544, Eugene, OR 97440, $12/year (4
issues).Worm Digest is a quarterly journal that covers the
use of worms in composting and soil improvement. This is a
great journal for anyone seriously interested in worm bins,
and especially for those interested in teaching others or
spreading the word about vermicomposting.
Videos:
COMPOSTING FOR THE 90's - A REASON AND METHOD FOR EVERYONE
from Earth to Earth Productions, P.O. Box 1272, Burbank, CA
91507-1272 (approximately 50 minutes long, ISBN
1-881647-02-1). This video covers everything from why to
compost, and different ways to make and use compost, to how
composting can save money on garbage bills. Very easy to
understand, and complete, yet concise. Recommended for new
composters who like how-to videos and for public
libraries/organizations that want to provide user friendly
how-to resources for their patrons.
WORMANIA!
from Flowerfield Enterprises, 10332 Shaver Road, Kalamazoo,
MI 49002 (26 minutes, with a 48-page teaching guide, $38.40,
ISBN 0-942256-07-7). Mary Appelhof has produced, partly with
the help of a National Science Foundation grant, this video
on the subject of worms and vermicomposting. In the video,
Worm Woman visits a family, teaches them about worm biology,
and helps them set up a worm bin for composting kitchen
wastes. Several worm-related songs by Billy Brennan make up
part of the video, which covers a lot of ground in a concise
fashion, but is entertaining and engaging. Microvideo is
used to illustrate worm anatomy. Worm movement,
feeding/digestion, and reproduction are all covered, as well
as the role worms play in improving soil drainage and
organic matter content. A great video for libraries, school
districts, master composter groups, and agriculture or
biology classes. This is not primarily a how-to video for
vermicomposting (use Mary Appelhof's excellent book Worms
Eat My Garbage for this purpose), but would be good for
general outreach to promote the idea of vermicomposting, or
as a supplement to how-to education.
Rot Web text (c)1996 by Eric S. Johnson
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