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How Compost Bins Work

By Kathryn Hatter ; Updated September 21, 2017

What Is Compost?

Many gardeners consider compost to be "black gold." Compost will improve the soil and add quality nutrients and drainage properties. Compost is also a useful mulch to place over the soil around the roots of plants. Gardeners who wish to begin making their own compost for use in flower and vegetable gardens can either make or purchase compost bins to contain the organic ingredients for mixing the compost. There are many suitable varieties of compost bins. Some are hard plastic, some are metal and some are wood. Gardeners can also make compost in piles or fenced-in areas without a bin to contain the compost, if desired. Select a location for your compost bin or pile that is close to the garden and your outside water source, if possible.

Mixing Compost Ingredients

Add a layer of brown organic materials to the compost bin first. These materials include dead plant foliage, sawdust, autumn leaves and pine needles. Saturate the brown materials with water. Add a layer of green materials next. Green materials include kitchen scraps (do not use milk or meat products), coffee grounds, weeds, horse manure and grass clippings. Saturate this layer with water also. The top layer is plain garden soil—sprinkle this over the saturated green materials. Spray the entire contents of the bin or pile with more water.

After adding the compost ingredients to the compost bin, mix them with a garden spade for best results. Some compost bins rotate from top to bottom and bottom to top to help mix the ingredients. If your compost bin has this design, rotate the bin every two weeks to facilitate faster compost creation. If your compost bin does not have that design, open the bin and use the garden spade to mix the compost ingredients.

Chemical Process of Composting

While the compost ingredients are inside the compost bin, a chemical process begins that involves the breakdown of the individual ingredients until they become unidentifiable. This process involves moisture, heat and air. The first stage of decomposition involves the metabolism of the simple carbohydrates of the compost ingredients. The temperature inside the compost bin begins to rise during this stage. The next stage of decomposition involves a greater increase in temperature and decomposition of the cellulose materials within the bin. It is very important to keep the compost ingredients well mixed and aerated during this period. During the last stage, the temperature decreases within the compost bin and the compost ingredients cure to become the final compost product.

The Finished Compost

The ingredients are ready to use as compost in a garden when they are dark brown and smell of the earth. The typical length of time for making compost is one year. Allow the compost to mature for several more months before using for best results. Many gardeners transfer the finished compost to another container and begin the process of making more compost in the bin immediately so they always have a plentiful supply of compost for use in their gardens.


About the Author


Kathryn Hatter is a veteran home-school educator, as well as an accomplished gardener, quilter, crocheter, cook, decorator and digital graphics creator. As a regular contributor to Natural News, many of Hatter's Internet publications focus on natural health and parenting. Hatter has also had publication on home improvement websites such as Redbeacon.