Most compost enthusiasts typically advise against giving children free reign to manage compost piles. Between their penchant for snowball fights and digging in dirt, many boys will turn your compost heap into a free-for-all. Girls, on the other hand, are more likely to declare the entire process as "gross" before wrinkling their noses and turning away in disgust. Familiarize kids with the art of composting by helping them start their own compost pile. Keep your sense of humor handy and be prepared to exercise patience as you guide tomorrow's composters through the fascinating process of building their very own compost heaps.
Explain the overall composting process to the children ahead of time. Avoid going into too much depth initially, but make sure they're aware that bacteria eat organic scraps and convert them into humus. Have several different examples of organic waste available for the kids to see, such as banana peels, dead leaves and grass clippings. Show the children a handful of mature compost so they can compare the original samples of organic matter to the broken-down humus.
Collect organic waste for the compost heap using buckets and plastic garbage bags. Talk about the difference between dry carbon-rich waste and wet nitrogen-rich materials as you gather the materials together. Have each child describe the different types of waste that they find in order to help guide them in making the connection between what you told them about composting and what they're doing. For example, encourage younger children to describe a dead leaf as "dry" and "brown" but emphasize the fact that it's a source of carbon if you're working with older children.
Spread a 3- to 4-inch layer of carbon-rich waste (such as dead leaves, shredded newspaper, straw and sawdust) across the bare ground in a 3 foot-by-3 foot area. Cover it with a 2- to 3-inch layer of nitrogen-rich waste (such as fresh grass clippings, vegetable peels and fruit scraps). Dampen the waste with enough water to make it about as wet as a wrung-out sponge; explain to the children that the microbes that will eat the organic waste need the moisture to stay alive. Alternate additional layers of damp carbon- and nitrogen-rich waste until the compost heap is at least 3 feet tall.
Limit the participation of the kids based on their ages. Allow children between the ages of three and five years to help by collecting the organic waste. Keep more detailed jobs, such as building the pile and adding moisture, for older children who have more advanced motor skills.