With the right ingredients and a few simple tools, you can turn grass clippings, leaves, branches, weeds, and some kitchen waste into sweet smelling humus that contains plant nutrients and retains moisture.

Composting speeds up the decay of these organic materials. The amount of time it takes to form humus depends on the materials used to make the compost pile, composting techniques, and the amount of effort you put into the process.

photo of compost bin
  Photo courtesy of Rodale Stock Images.

Freestanding compost piles can be left alone, and over time, they will decompose, depending on moisture and temperature. This method takes little effort, but requires more space than home composting units, which contain the pile, keep animals from digging into it, and allow you to aerate the compost, so it can decay faster.

Most organic material can go into your compost pile: leaves, branches, weeds, grass clippings, vegetable kitchen waste, saw dust, wood chips, egg shells, tea bags, coffee grounds, paper coffee filters, and paper towels.

BUT you shouldn't use:

So what happens inside the compost pile?

Bacteria, fungi, and other microorganisms break down the organic material inside the pile. Microorganisms that live in temperatures from 50° - 113° F (10° - 45° C) begin the decomposition process. The microorganisms generate heat as they consume and digest the material in the pile. As the pile heats up, other microorganisms that live in temperatures from 113° - 158° F (45° - 70° C) take over the decomposition process.

The bacteria that decompose the pile require moisture and oxygen. If the pile is too dry, or if bacteria use up the available oxygen, the temperature drops and the decomposition process slows down. Turn the pile to add air and keep it moist. If the conditions are just right, you'll have rich compost in as little as three weeks.

activity icon Activities: Best Ever Compost (for outdoor composting), and Soda Bottle Bioreactor (for small-scale indoor composting)
profile icon Profile: Seattle Tilth Association

Back Rotten Truth home Next

© The Rotten Truth web site was created in 1998 by the Association of Science-Technology Centers Incorporated and the Smithsonian Institution Traveling Exhibition Service. All rights reserved.
Disclaimer: Rotten Truth (About Garbage) links to a number of activities and resources provided by institutions other than ASTC and SITES. Every effort has been made to ensure that these links are accurate, but because neither ASTC nor SITES controls the content of these web sites, outside links are not guaranteed to be correct or active. Neither ASTC nor SITES shall be liable in the event of incidental or consequential damages connected with, or arising out of, providing the information offered here. External sites are not endorsed by ASTC or the Smithsonian Institution.