Here’s what you need:
2. Nitrogen-rich “green” materials, such as grass clippings, plant-based kitchen waste (vegetable peelings and fruit rinds, but no meat scraps), or barnyard animal manure (even though its color is usually brown, manure is full of nitrogen like the other “green” stuff). Do not use manure from carnivores, such as cats or dogs.
3. A shovelful or two of garden soil.
4. A site that’s at least 3 feet long by 3 feet wide.
Here’s what to do:
Continue layering green stuff and brown stuff with a little soil mixed in until the pile is 3 feet high. Try to add stuff in a ratio of three parts brown to one part green. (If it takes awhile before you have enough material to build the pile that high, don't worry. Just keep adding to the pile until it gets to at least 3 feet high.)
Every couple of weeks, use a garden fork or shovel to turn the pile, moving the stuff at the center of the pile to the outside and working the stuff on the outside to the center of the pile. Keep the pile moist, but not soggy. When you first turn the pile, you may see steam rising from it. This is a sign that the pile is heating up as a result of the materials in it decomposing. If you turn the pile every couple of weeks and keep it moist, you will begin to see earthworms throughout the pile and the center of the pile will turn into black, crumbly, sweet-smelling “black gold.” When you have enough finished compost in the pile to use in your garden, shovel out the finished compost and start your next pile with any material that hadn’t fully decomposed in the previous one.
You don’t need a compost bin to make compost. You simply need a pile that is at least 3 by 3 by 3 feet. A pile this size will have enough mass to decompose without a bin. Many gardeners buy or build compost bins, however, because they keep the pile neat. Some are designed to make turning the compost easier or protect it from soaking rains.