Composting is simply the process of breaking down the organic matter (food waste) in the presence of air and water, using micro organisms and small insects present in nature. The end product is called compost which is rich in readily usable plant nutrients forming a part of healthy soil.
Uses of Compost – Gardeners use compost in many ways. It is used in establishing a planting bed; improving soils; mulching gardens or landscape plantings; backfilling during the planting of trees, shrubs, or perennials; side-dressing vegetables; or controlling erosion
Composting organisms require 4 conditions to create compost:
Carbon that comes from brown organic matter like dried leaves, sawdust, paper, shredded newspaper, hay, straw, and eggshells
Nitrogen that comes from green plants, grass clippings, vegetable and fruit scraps, coffee grounds, and tea bags
Oxygen which comes from air
Water in the right amounts
What Can I Compost?
Yard trimmings, such as fallen leaves, grass clippings, small branches, weeds and the remains of garden plants.
Kitchen scraps EXCEPT FOR meat, fish, bones and fatty foods (such as cheese, salad dressing and leftover cooking oil). Egg shells are fine to add.
Large woody branches that are cut, chipped or shredded into pieces can be added to a compost system to create air spaces in the pile. Woody material can be chipped into smaller pieces and used as a mulch or for paths, where they will eventually decompose
How Do I Start Composting?
Begin by collecting yard trimmings and throwing them in your pile or bin. You can then add yard trimmings and food scraps anytime but it is best to bury the food scraps in your pile. Chopping or mowing your materials makes the process go faster.
Food scraps should be added to the center of the waste layers where heat will be the greatest. This also reduces unwanted critters coming to your compost pile.
Pile material loosely in the bin. Too much compaction inhibits the flow of air through the pile. Wood chips or course weeds will create air pockets which help provide oxygen to the microorganisms.
Water is key to successful composting. A compost pile should be kept damp – but not soggy – especially during dry spells.
How Does Composting Work?
Many organisms are involved in the composting process. They include bacteria, fungi, protozoans and centipedes, millipedes, beetles, ants and the most famous – earthworms! Composting is an aerobic process (requires oxygen), since these organisms use oxygen as they break down the materials and turn them into compost.
In addition to oxygen, compost organisms need water to thrive. That is why the compost pile must be kept moist. If there is too much water not enough air can get to the microorganisms. Use the squeeze test to find out if you have the right amount of moisture. Grab a handful of material and squeeze. If a few drops come out, you’re doing great.
Compostable materials contain carbon and nitrogen. We refer to them as greens and browns. Greens are fruit and vegetable wastes, coffee grounds, grass clippings, manure. Browns are leaves, straw, wood chips, sawdust and shredded paper. The microorganisms use the carbon in leaves and other browns as an energy source. As the microbes breakdown this material, heat energy is released. Nitrogen helps the microbes build proteins to grow and multiply. The decomposing organisms need a certain amount of both carbon and nitrogen to work well. Approximately 1 part greens to 2 part browns is a good mix.
Chopping or mowing your compost materials speeds the process since it provides more surface area for the compost organisms. As the creatures decompose the materials into compost, the height of the pile will reduce by over 50%!
For optimum composting, the compost temperature should be around 90 to 140 degrees Fahrenheit. The pile will be hot soon after adding materials and then will cool down. Here in New York State, unless you have a big pile that keeps in the heat, composting will shut down for the winter as the microorganisms become inactive. This is not a problem, because the composting process will start up again when the weather gets warmer. However, if you want to add food scraps to your compost pile through the winter, you can insulate the pile.
Why Should I Make Compost?
Composting is an easy, practical way to recycle your organic yard and kitchen waste. • Compost is an excellent soil conditioner for even the smallest yard and garden – it’s safe to use and it costs practically nothing to make. • Compost grows healthy plants and healthy plants improve the air by removing carbon dioxide and making fresh oxygen. • For serious gardeners, compost is an inexpensive alternative to peat and other soil enhancements.
Easy steps to compost your kitchen waste
Separate your edible kitchen waste like vegetable peels, fruit peels, small amounts of wasted cooked food in a container
Collect dry organic matter like dried leaves, sawdust in a small container
Take a large earthen pot or a bucket and drill 4 – 5 holes around the container at different levels to let air inside.
Line the bottom with a layer of soil.
Now start adding food waste in layers alternating wet waste like food scraps, vegetable and fruit peels with dry waste like straw, sawdust, dried leaves.
Cover this container with a plastic sheet or a plank of wood to help retain moisture and heat.
Every few days, use a rake to give the pile a quick turn to provide aeration. If you think the pile is too dry, sprinkle some water so that it is moist.
Within 2 – 3 months, your pile should start forming compost that is dry, dark brown and crumbly and smelling of earth. There are also readymade composting kits available for those who want to overcome initial resistance to starting composting
Composting Do’s And Don’ts
DO mix grass clippings with other wastes to loosen them up. They have a tendency to compact. The best way to manage grass clippings is to mulch them into the lawn.
DO keep the compost pile damp, especially during dry spells. Squeeze test.
DON’T use unfinished compost. It will rob your plants of nitrogen.
DON’T add dog and cat droppings. They can contain diseased organisms that may not be destroyed through the compost. DON’T compost weeds that are heavily laden with seeds. Some seeds will not be killed during the heating process.
DON’T add diseased vegetable plants to the pile if the compost will be used on a vegetable garden. The disease organisms may reappear the following year.
DON’T add meat, fish, bones or fatty food scraps to the compost mixture. They will attract animals (dogs, cats, rats, etc.) and they do not decompose readily.
Troubleshooting and Often Asked Questions
(source: University of Maryland, Home and Garden Information Center)
Should I cover the pile or bin?
Covering is not necessary, but it may help control evaporation and conserve nutrients. Rainfall can be a real benefit during dry periods.
Should I add soil? Bioactivators?
Soil is not necessary and could compact the pile and displace oxygen. Bioactivators are not necessary. To kick-start a newly charged bin, simply add a few shovels full of compost.
Should I attempt to compost pine needles? Oak leaves? Holly leaves? Walnut leaves?
Certainly. Tough pine needles and holly leaves will take longer. Newly shed oak leaves are acidic but will be pH neutral when composted. Walnut leaves contain little, if any, of the toxin juglone. (Most of that chemical is produced by walnut roots and remains in the soil.) The composting process breaks down juglone.
What happens to weed seeds? Diseased plants?
Even though hot composting will usually kill most weed seeds, one should avoid adding weeds that are in flower or have seed heads. Many disease pathogens are killed by hot composting, but…when in doubt, leave it out.
Should I compost kitchen scraps?
Many kitchen scraps are welcome additions to your compost pile/bin. Save vegetable and fruit parings, rinsed egg shells, coffee grounds and filters, tea bags, stale bread, etc. Be advised, however, some municipalities may have restrictions on the backyard composting of kitchen scraps. Indoor redworm composting and trench composting are good alternatives for kitchen scraps.
Should I use treated lumber to construct my compost bin?
It is best to avoid using treated lumber (ACQ or copper azoles) in the fabrication of a compost bin. Also avoid adding sawdust from treated lumber to the compost bin/pile.
Should I use grass clippings that have been treated with herbicides (weed killers)?
Although many herbicides break down within a few weeks or months, some others can survive the compost process and have an adverse effect on plant material. Leave out any treated grass clippings.
Why is the pile/bin not heating up?
This could be the result of insufficient nitrogen. Or, the pile/bin could be too wet (inadequate oxygen), or too dry (insufficient moisture). If too wet, turn the heap to dry it out. If too dry, add water. If the moisture is ok, add a nitrogen source.
Why does my compost smell bad?
This is the result of anaerobic digestion and could be caused by too many nitrogen-rich materials (lots of matted grass clippings) or too much water. Turn the pile and add some shredded newspaper, straw, or sawdust to dry it out.
Where should I place my pile/bin?
The microbes don’t really care. Make yourself comfortable. In full sun, you may have to add water more frequently. In shade, you may have to share the nutrients with the nearby plants as their roots invade the pile. Avoid placing bins next to wooden structures – moisture can attract termites.
Do I have to add materials in layers?
No. It works, but it is better to mix the ingredients thoroughly. Layering is often suggested since it requires less labor.
Can I add fertilizer to my compost pile/bin?
Yes, but don’t rely on inorganic fertilizer as your sole source of nitrogen. Organic sources include blood meal or dried blood, cottonseed meal, alfalfa meal, even nitrate of soda.
Will fabrics compost?
Yes, but avoid wool. Animal products tend to break down anaerobically. Cotton is an excellent source of carbon, so don’t hesitate to add old tee shirts, or other discarded 100% cotton fabrics to the compost pile. Also, don’t forget to add the lint from your clothes dryer.
Now that I’ve got it, what do I do with it?
NYC MASTER COMPOSTER MANUAL – NYC.gov
City of Seattle Public Utilities
Cornell Waste Management Institute
Frequently Asked Questions About Worms in Composting
Frequently Asked Questions (FAQ’s) About Composting
Frequently Asked Questions: Yard Waste/Organics/Composting
Home Composting faq
FAQS ON COMPOSTING LEAVES
Backyard Composting Frequently Asked Questions
Master Composter Manual
Compost Tips for the Home Gardener