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How Long Does it Take Compost to Become Dirt?

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Compost is an easy and effective way to obtain organic matter for your garden while also reducing kitchen and yard waste. The amount of time it takes for compost to complete the decomposition process depends on a variety of factors, so research various composting techniques before you decide what kind of compost pile to create.

Cold Compost

The time it takes for compost to decompose depends largely on whether you decide to use a hot or cold composting method. Cold compost is also known as passive compost as there is little or no turning involved. You simply make a large pile of compost, which decomposes on its own with little intervention. Cold composting needs to be done outdoors and is suitable for most backyards. It also requires minimal effort compared to hot composting. However, it takes several months or even as long as a year for the materials to decompose, according to the United States Department of Agriculture (USDA) Natural Resources Conservation Service.

Hot Compost

Hot compost is a much faster way to create finished compost. Unlike cold composting, hot composting requires regular turning to generate heat in the core of the compost pile, which helps the materials decompose much faster than they do on their own. According to the Oregon State University Extension Service, hot compost piles can be turned into dirt in as little as eight to 10 weeks. However, they do require more maintenance than cold compost piles, and you must be careful to create a perfect balance of green materials, such as vegetable scraps, and brown materials, like leaves and sticks.


Of course, the size of your compost pile also influences how fast it decomposes. If your pile is too small, it may not be able to generate enough heat to decompose materials. On the other hand, large piles may not receive enough oxygen. The University of Illinois Extension Service recommends keeping your compost pile between 3 and 5 cubic feet for best results. If there are diseased plants or trees in your compost pile, however, a larger size is needed in order to destroy pathogens.

Other Factors

The type of materials in your compost pile also influences how long it takes to turn into dirt. High amounts of brown materials take longer to decompose so add green materials to the pile in order to speed up the decomposition process. You can also add a nitrogen fertilizer to the pile at a rate of 1 cup per 25 square feet, according to the University of Illinois Extension Service. For quicker results, consider shredding and breaking up large materials, such as sticks or leaves, in order to encourage bacterial decomposition.

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