As yard and kitchen wastes decompose in a backyard compost pile, banana peelings, coffee grounds and grass clippings transform into rich, crumbly compost that adds nutrients back into soil. In the warm, moist environment of a compost pile bacteria, fungi and other microorganisms break down organic matter. Start your compost pile off right and maintain it properly to encourage faster decomposition.
Chop the waste added to the compost pile into small pieces. Smaller pieces break down faster. The Cooperative Extension Service of South Dakota State University has determined that ½ inch to 4 inches is the optimum size for pieces of material in a compost pile. You can chop materials by running a lawnmower over them, or simply chop kitchen waste with a knife.
Layer different types of material in your compost pile. Yard waste such as grass clippings and leaves should be alternated with vegetable peelings, coffee grounds and other kitchen wastes. Don't add meat scraps, oils or fats, or large quantities of twigs, as they will slow down decomposition or attract pests.
Aerate the compost pile by turning it frequently. The microbes that break down waste into compost need oxygen to work. Turning the pile allows more oxygen to enter, accelerating decomposition. Turn the pile once a week.
Water the pile in dry weather. Microbes like a warm, moist environment. Keep the compost pile moist, but not so wet water runs out of it. A soggy compost pile holds less oxygen.
Add an accelerator. A properly built compost pile won't need additives to speed up decomposition, but if you live in an area with a short growing season or you want your pile to break down more quickly, you can add nitrogen in the form of manure, a nitrogen fertilizer, or even beer. One experiment by students in Wisconsin found that beer added to compost accelerated the amount of decomposition, at least during warm months.