Wednesday, February 24, 2010

Compost it!

Sad to say that it's been a while, folks. The difficult part about writing a blog about farming when it's winter is that, well, it's winter time. Which tends to leave this blogger's brain short on ideas, which would otherwise be swimming with material during warmer months. Regardless, our Humble Farmer suggested that I blog about composting and vermiculture, so here goes!

An Introduction to Composting

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.

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.

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) 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. 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!

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:


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.


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.


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.


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'.


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.


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" and will resprout in the compost pile -- avoid using these unless they are thoroughly dead. Green weeds are (you guessed it) 'green', while dead brown weeds are 'brown'.


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.

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:


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.


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 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.


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.


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.


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.

Composting Systems: Vermicomposting/Worm Bin Composting

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.

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.

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. You may wish to read the vermicomposting guide available on the World Wide Web from CITY FARMER, an organization in British Columbia.

I hope that you've found this blog informative and helpful, and will hopefully feel inspired to start your own composting project. This year at Hand in Hand, I'll be working with the Core Group to expand our current composting efforts. If you're a CSA family member that is not already home composting and you would like to drop off your appropriate scraps to our pile, please contact us and let us know.

Thanks for reading!

The Farmer Babe

The Farmer Babe ©2010

Composting Resource List

Online Resources:



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.


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.


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.


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.


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.


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.


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.



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.


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.

No comments:

Post a Comment