- Composting Basics
- Types of Compost Units
- Troubleshooting Your Compost
- Composting Is Not For Me
- Other Links
Composting is the biological process of converting organic waste under controlled conditions into a product that provides organic matter and nutrients to the soil. Compost improves soil texture, promotes new plant growth, can suppress some plant diseases, and can prevent soil erosion when used as cover for seeded grasses.
There are two basic types of compost:
- Yard Waste Compost - utilizes organic waste from lawns and gardens, such as grass, leaves, and twigs, to create an effective soil amendment.
- Food Waste Compost - uses food waste such as fruit and vegetable trimmings and kitchen preparation residuals. Together, yard and food wastes comprise nearly 22% of municipal solid waste.
(from the Cornell Cooperative Extension)
Composting is the most practical and convenient way to handle your yard wastes. It can be easier and cheaper than bagging these wastes or taking them to a transfer station. Compost also improves your soil and the plants growing in it. If you have a garden, lawn, trees, shrubs or even planter boxes, you have use for compost.
By using compost you return organic matter to the soil in usable form. Organic matter in the soil improves plant growth by helping to break up heavy clay soils and improving their structure, by adding water and nutrient-holding capacity to sandy soils, and by adding essential nutrients to any soil. Improving your soil is the first step toward improving the health of your plants. Healthy plants help clean our air and conserve our soil, making our communities healthier places in which to live!
What Can I Compost?
Anything that was once alive can be composted. Yard wastes, such as fallen leaves, grass clippings, weeds and the remains of garden plants, make excellent compost. Woody yard waste can be clipped or sawed down to a size useful for the wood stove or fireplace, or they can be run through a shredder for mulching and path making. Used as mulch or for paths, they will eventually decompose and become compost.
Note: Care must be taken when composting kitchen scraps. Compost them only by the methods outlined on this page. Meat, bones, and fatty foods (such as cheese, salad dressing, and leftover cooking oil...or anything cooked in it) should be put in the garbage.
How Can I Use Compost?
Compost can be used to enrich the flower and vegetable garden, to improve the soil around trees and shrubs, as a soil amendment for houseplants and planter boxes and, when screened, as part of a seed starting mix or lawn top-dressing. Before it decomposes, chipped woody waste makes excellent mulch or path material. After it decomposes, woody wastes will add texture to garden soils.
- Biology - Think of a compost operation as a miniature farm. The compost is a teeming microbial farm. Tiny bacteria start the process of decaying organic matter. They are the first to break down plant tissue and also the most numerous and effective composters. Fungi and protozoans soon join the bacteria, and somewhat later in the cycle, centipedes, millipedes, beetles, and earthworms do their parts.
- Materials - Anything growing in your yard is potential food for these tiny farmers, or decomposers. Carbon and nitrogen, from the cells of dead plants and dead microbes, fuel their activity. The micro-organisms use the carbon in leaves or wood wastes as an energy source. Nitrogen provides the microbes with the raw element of protein to build their bodies. Organic material has a ration of carbon to nitrogen (C:N) in its tissues, ranging from 500:1 for sawdust, to 15:1 for table scraps. A C:N ratio of 30:1 is ideal for the activity of compost microbes. This balance can be achieved by mixing two parts grass-clippings (with a C:N ratio of 20:1), with one part fallen leaves (60:1) in your compost. Layering can be useful in arriving at these proportions, but a complete mixing of ingredients is preferable for the composting process. Other materials can also be used, such as weeds and garden wastes. Though the C:N ratio of 30:1 is ideal for fast, hot compost, a higher ratio (i.e., 50:1) will be adequate for a slower compost.
- Surface Area - The more surface area the micro-organisms have to work on, the faster the materials are decomposed. It's like a block of ice in the sun - slow to melt when it's large, but melting very fast when broken into smaller pieces. Chopping your garden wastes with a shovel, or running them through a shredding machine or lawnmower will speed composting.
- Volume - A large compost pile will insulate itself and hold the heat of microbial activity. The pile's center will be much warmer than its edges. Piles smaller than 3 feet cubed (27 cu. ft.) will have trouble holding heat, while piles larger than 5 feet cubed (125 cu. ft.) won't allow enough air to reach the microbes at the center. These proportions are of importance only if your goal is a fast, hot compost.
- Moisture and Aeration - All life on earth needs a certain amount of water and air to sustain itself. The microbes in the compost pile are no different. They function best when the compost materials are about as moist as a wrung-out sponge, and are provided with many air passages. Extremes of sun or rain can adversely affect the moisture balance in your pile.
- Time and Temperature - The faster the composting, the hotter the pile. If you use materials with a proper C:N ratio, provide a large amount of surface area and a big enough volume, and see that the moisture and aeration are adequate, you will have a hot, fast compost (hot enough to burn your hand!).
THE SIMPLEST COMPOST - BURYING FOOD/SOIL INCORPORATION
Burying your organic waste is the simplest method of composting.
|Which Wastes?||Kitchen scraps without meat, bones or fatty foods (or foods cooked in fat).|
|How?||Everything should be buried at least 8 inches below the surface. With 8 inches of cover, be sure to allow for the depth of the waste. Holes can be filled and covered, becoming useful garden space the following season.|
|Advantages and Disadvantages?||This is a simple method, but the absence of air results in loss of some nutrients. Rodents and dogs can become a problem with wastes buried less than 8 inches deep.|
|Variations||Using a post-hole digger, wastes can be incorporated into the soil near the drip line of trees or shrubs and in small garden spaces.|
For yard waste, this is the simplest method.
|Which Wastes?||Non-woody yard wastes are the most appropriate.|
|How?||Place the holding unit where it is most convenient. As weeds, grass clippings, and harvest remains from garden plants are collected, they can be dropped into the unit. Chopping or shredding wastes, alternating high carbon and high nitrogen materials, and keeping up good moisture and aeration will all speed up the process.|
|Advantages and Disadvantages?||The units can be portable, and moved to wherever needed in the garden. This method can take from six months to two years to compost organic materials, so you need to be patient.|
|Variations||Holding units can be made of hardware cloth, old wooden pallets, or wood and wire. Sod can be composted with or without a holding unit, by turning sections of it over, making sure there is adequate moisture, and covering it with black plastic.|
This is a series of three or more bins that allow wastes to be turned on a regular schedule. Turning units are appropriate for gardeners with a large volume of yard waste and the desire to make high-quality compost.
|Which Wastes?||Non-woody yard wastes are the most appropriate. Kitchen wastes without meat, bones or fatty foods can be added to the center of a pile if it is turned weekly and reaches high temperatures. If the proper temperature is not achieved, or the pile is not turned frequently enough, you might attract unwanted guests and odors to your pile.|
|How?||Alternate layers of high-carbon and high-nitrogen to approximately a 30:1 ratio. The layers should be moistened to the damp sponge stage. The pile temperature should be checked regularly. When the heat decreases substantially, transfer the pile into the next bin. Dampen the materials if they are not moist, and add more high-nitrogen material if heating is not generated. Start a new pile in the original bin. Repeat the process each time the pile in the first bin cools. After two weeks in the third bin, the compost should be ready for garden use. An excellent source for information on hot composting is the Rodale Guide to Composting which can be found in most libraries.|
|Advantages and Disadvantages?||This method produces a high quality compost in a short period of time utilizing a substantial input of labor.|
|Variations||The unit can be built of wood, a combination of wood and wire, or concrete block. Another type of turning unit is the barrel composter, which tumbles the waste for aeration. The most common type of barrel composter is made from old, clean 55-gallon drums. Variations include simply leaving the barrel on the ground and rotating it 90-degrees every week.|
Feeding earthworms (red wiggler worms work best!) in wooden, or plastic bins are a good way to make very high quality compost from your clean kitchen scraps. For more information on red wiggler worms go to http://www.vermitechnology.com.
|Which Wastes?||Kitchen scraps without meat, bones or fatty scraps.|
|How?||Fill a bin with moistened bedding such as peat moss or strips of newspaper (1 inch wide maximum). Rotate burying of food wastes throughout the worm bin. Every three to six months the worm population should be divided and moved to fresh bedding. For detailed information on how to compost with red wigglers, see Mary Applehof's, Worms Eat My Garbage which can be found in most libraries.|
|Advantages and Disadvantages?||This is an efficient way to convert food waste into high quality soil for houseplants, seedling transplants, compost tea to spray on the lawn or water your houseplants, or general garden use. The worms are also a useful product for fishing. However, worm composting is more expensive and complicated than soil incorporation (burying food) for dealing with food wastes.|
For information on building a compost setup on your own visit: https://compost.css.cornell.edu/garbagecans.html
BUILDING YOUR COMPOST PILE
Prepare the materials. Collect one cubic yard of material (3'x3'x3') for a hot pile (quantity does not matter in a cold pile). Ensure you have both nitrogens (grass clippings, manure) and carbons (leaves, dried hay) available, and shred those carbons that are more than 1 - 2 inches in size.
Build the pile. You may simply throw in organic materials as they become available. This will result in a very slow decomposition process, but may be appropriate if you are not in immediate need of finished compost. If you are building a pile using the batch process for faster decomposition (more than one bin, turning units) follow these steps:
- Wet the ground under the pile;
- Put twigs or other unshredded carbons on the bottom of the pile to provide some aeration at the base;
- Layer the rest of your materials, alternating nitrogen and carbon layers, adding water as you go;
- Make sure you end with a carbon layer.
- Cover the pile (optional). Experts disagree on whether a cover is necessary. If you live in a region that is excessively dry or wet, cover the pile with a black plastic garbage bag to retain moisture or guard against rain (for bin-less piles). If you build your own bin, try an old piece of plywood or particle board. Remember to anchor the lid with a large rock or secure with small hinges. Add a rust proof handle for easy access.
- Monitor the pile (optional). Check to see that your pile becomes hot within a few days. The heat within the pile should peak again after turning. After that, it should peak every time you turn it, although the temperature will be lower and lower each time. Also monitor the moisture content of your pile. When you pick up a handful of material, it should feel like a wrung out sponge.
- Turn the pile (optional). Turning the pile allows all the material to be exposed to the hot center and will increase aeration and decrease composting time. Frequency can range from once a week, to once a month depending on the temperature.
Are you having problems with your compost? Does the compost have a bad odor? Is the center of the pile dry? Take a look at the reference guide below for quick answers to your compost problem. If your problem can't be solved here, you can always check out the Cornell Cooperative Extension's web page for more information.
|The compost has a bad odor||Not enough air||Turn it|
|The center of the pile is dry||Not enough water||Moisten materials while turning the pile|
|The compost is damp and warm in the middle, but nowhere else||Too small||Collect more material and mix the old ingredients into a new pile|
|The heap is damp and sweet smelling but still will not heat up||Lack of nitrogen||Mix in a nitrogen source like fresh grass clippings, fresh manure, bloodmeal or ammonium sulfate|
Rodents, racoons and even house pets can be a concern associated with backyard composting. They can be attracted to compost piles both as a source of food and a place to live. Visit Cornell Cooperative Extension's website for help in preventing these problems.
WHAT CAN I DO?
Yard wastes can be useful for weed control and water retention.
Which Wastes? - Woody yard wastes, leaves and grass clippings.
How? - You can simply spread leaves or grass clippings beneath plantings. For woody materials up to 1 in diameter, rent or purchase a chipper/shredder. Tree services, if they are in your neighborhood, often will deliver wood chips for free.
Advantages and Disadvantages? - All yard waste will work first as a mulch and then, as decomposition proceeds, as a soil enrichment. A disadvantage of mulching with woody yard waste is that you may have to buy or rent a chipper/shredder or make arrangements with a tree service.
Variations - Use chipped materials for informal garden paths.
Follow these links for more information on composting!
Many of these pages have links to other pages too!