It always amazes me that people buy large, heavy duty black plastic bags (that probably take 500 years to biodegrade), spend all fall raking up leaves to put in these bags, (good exercise) and then put those bagged leaves out by the curb for trash pickup. When all they have to do is leave them in a pile and they will bio-degrade and be gone by spring and then you have a nice compost pile. Or just leave them on the lawn. I rarely see any signs of them in the spring and our ground is the better for it.

Nature creates compost all the time without human intervention. But gardeners can step in and speed up the composting process by creating the optimal conditions for decomposition:

Air + Water + Carbon + Nitrogen = Compost

Like most living things, the bacteria that decompose organic matter, and the other creatures that make up the compost ecosystem, need air. Compost scientists say compost piles need porosity—the ability for air to move into the pile. A porosity pile has to have plenty of spaces—or pores—for air to move about. A flat, matted pile of, say, grass clippings does not. Even fluffy piles compress during the composting process. Occasionally turning your pile aerates the material, moves new material into the center, and helps improve air flow into the pile.

Compost microbes also need the right amount of water. Too much moisture reduces airflow, causes temperatures to fall, and can make the pile smell too little water slows decomposition and prevents the pile from heating. Compost should feel like a wrung-out sponge.

The microbes that break down organic matter use carbon as an energy source. Ingredients with a high percentage of carbon are usually dry and brown or yellow in color. The most common high-carbon ingredients are leaves, straw, and corn stalks. Sometimes people call these ingredients browns. I had a Mantis composter one time and I could never get the "Browns" correct and then Microbes need nitrogen for the proteins that build their tiny bodies. Ingredients high in nitrogen are generally green, moist plant matter, such as leaves, or an animal by-product, such as manure. These ingredients are called greens, but in reality they can be green, brown, and all colors in between.

I could never get the C/N ratio correct in that composter. In order for a compost pile to decompose efficiently, you need to create the right ratio of carbon (C) to nitrogen (N) (C/N). Piles with too much nitrogen tend to smell, because the excess nitrogen converts into an ammonia gas. Carbon-rich piles break down slowly because there's not enough nitrogen for the microbe population to expand. An ideal compost pile should have a 30:1 C/N ratio. Grass clippings alone have about a 20:1 C/N ratio. Adding one part grass clippings, or other green, to two parts dead leaves, or other brown, will give you the right mix.

I found that for me, building a compost pile was the simplest solution and since there are two main ways to make compost: cold compost (minimum effort) and hot compost (maximum effort), I chose the cold compost.

This is often referred to as cold Black Gold and I find that most gardeners do this type of composting in their own backyards because it's easy. The recipe is simple:

Mix together yard wastes, such as grass clippings, leaves, and weeds, place them in a pile, and wait 6 to 24 months for the microorganisms, earthworms, and insects to break down the material. Add new materials to the top of the pile. You can reduce the waiting period by occasionally turning the pile and monitoring and adjusting the pile's moisture level. The compost will be ready when the original ingredients are unrecognizable. Generally, compost on the bottom of the pile "finishes" first. Don't add any woody material, as it breaks down too slowly.

The best part of this is that it takes little effort to build and maintain can be built over time. The bad news is that it takes up to two years to produce finished compost doesn't kill pathogens and weed seeds under composed pieces may need to be screened out.

For those who like the hot composting method here are some good hints to get high quality compost with a little more work and the right ingredients and hopefully only two months of time. Wait until you have enough material to create compost critical mass (27 cubic feet), which is the minimum volume for a pile to hold heat. Then mix one part green matter with two parts brown matter. Bury any vegetative food scraps in the center to avoid attracting animals. Never add meat scraps. Check to make sure the mixture has the ideal moisture level. Continue adding mixed greens and browns and checking the moisture until you've built a pile that is 3 feet x 3 feet x 3 feet, or 5 feet wide at the base and 3 feet wide at the top.

The microorganisms will immediately start decomposing, and their bodies will release heat. The pile will insulate the heat, and the temperature of the pile's interior will reach 120 to 150 degrees F. Turn the pile weekly and regulate moisture levels. After about a month, the hot phase will be done, and the pile will finish decomposing at temperatures between 80 degrees F and 110 degrees F. The compost will be ready to use when it no longer heats and all of the original ingredients are unrecognizable.

The best part of this is that it produces high-quality compost within 2 months (and sometimes as soon as a few weeks) can kill weed seeds and pathogens. The bad news is that it is time-consuming requires careful management of moisture, air, and C/N ratio. The whole process lies with you and your tastes. I found this list that seems to be fairly conclusive in what works or doesn't work when building your compost heap.

Green goodies

Aquarium water, algae, and plants (from freshwater fish tanks only) add moisture and a kick of nitrogen.

Chicken manure has high amounts of nitrogen, phosphorus, and potassium.

Dead houseplants add a dose of nitrogen, but don't include thorny or diseased plants.

Fresh grass clippings should be mixed with plenty of drier, brown material, or you'll risk creating a smelly pile.

Green garden debris, such as spent pansies, bolted lettuce, and deadheaded flowers, can all be recycled in the compost bin.

Horse manure contains more nitrogen than cow manure.

Manure from pet rabbits and rodents (e.g., gerbils and hamsters) can be composted with the accompanying wood or paper bedding.

Vegetative kitchen scraps (carrot peelings and the like) should be buried in the pile so they don't attract animals. Eggshells are okay, too.

Weeds can be composted! Yes they can as long as you remember never to add weeds that have set seed or weeds that root easily from stems or rhizomes, such as field bindweed and Canada thistle.

Brown goodies

Brown garden debris, such as corn and sunflower stalks, dried legume plants, and dried potato and tomato vines, adds bulk to the pile.

Hedge prunings and twigs help keep a pile fluffy but should be chipped first so they decompose faster.

Leaves are an abundant carbon source and full of nutrients. Stockpile them in fall so that you have them on hand in summer.

Pine needles decompose slowly. Add only small amounts to your pile. Use excess needles as mulch.

Straw bulks up a pile, but it should not be confused with hay, which often contains weed and grass seeds and shouldn't be added to compost (unless you want to deal with the potential consequences).

The following items should never be added to compost, because they could introduce harmful pathogens, toxins, and non biodegradable material:

Diseased plants must be disposed of in the garbage or burned. Adding them to compost could spread the disease.

Dog, cat, pig, and reptile manures (and associated bedding) may contain parasites or dangerous pathogens that are harmful to humans, particularly pregnant women, children, and people with compromised immune systems. Never add them to your compost.

Gypsum board scraps could contain paint and other undesirable toxins.

Materials from the side of the road, including grass clippings and leaves, could contain petroleum residues (such as oil), toxins, and non-biodegradable materials.

Meats, dairy products, bones, and fish decompose slowly, smell, and attract animals and rats!!!!

Paper, especially glossy paper, printed with colored ink, may contain heavy metals. Black-and-white newspaper is safe.

Many things found in the average home are nontoxic and biodegradable and come from a known source but they aren't great compost ingredients because they break down slowly, mat together, or don't add many nutrients.

Black-and-white newsprint and office paper can be used in the compost pile if you're desperate for brown materials, but they must be shredded. We used the newspaper in sheet mulching projects and recycled and shredded office paper instead.

Cardboard is best used in sheet mulching. Shred or chop it into small pieces if composting. Dryer lint may contain synthetic fibers that will never decompose. Even natural-fiber lint adds no benefit to compost.

Human and pet hair can be added in small amounts, if you keep in mind that it breaks down slowly, mats easily, and sheds water.

Natural-fiber cloth doesn't add any benefit to the compost pile. Consider using burlap bags under wood chips to prevent weeds instead.

Sawdust must be used in moderation, because it breaks down very slowly and can lock up nitrogen. Never use sawdust from treated or painted wood.

Vacuum bags may contain synthetic carpet fibers and other nonbiodegradable items.

Wood ash adds potassium (potash), but it is an extremely alkaline material and should be used in small amounts.

Wood chips should be used as mulch around ornamentals because they break down so slowly.


Cow manure may contain E. coli O157:H7, a very dangerous pathogen that can cause severe illness and even death. You must wait at least four months after you add it to your soil before you can harvest, to make sure the pathogens are no longer active. Always wear gloves when handling manure and wash your hands thoroughly. When we had the dairy farms, we used to pile the manure up for several months before we spread it in the fields.

Author Bio Box: Arlene Wright Correll

Resources: Excerpted from “Food For Thought Series” by Arlene Wright-Correll. For more gardening or cooking information click and click on Arlene’s Books you can download or buy my gardening & cook books. All my royalties from the sale of my books go to the St. Jude Children’s Research Hospital and we thank you for your attention to this site.

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Comment (1)

We compost at our house and leave the leaves in a pile, but honestly, it does take a long while for the leaves to disappear. Great post. I enjoy the articles. I found your blog through BF.