Making compost with kids not only teaches them how soil is formed it gives them an opportunity to learn the importance of creating a natural soil amendment that does not rely on commercial products. Providing them with the means to watch the process up close in a small container encourages them to become active participants in the process. With a few simple household containers, they can make compost on a sunny windowsill.
Remove the label from a 2-liter soda bottle. Soaking the bottle in warm water for a few minutes will loosen the label, making it easy to peel off. Rinse to remove any soap residue. Set aside to air dry.
Spray the outside of the bottle with flat black paint and allow to dry completely.
Cut a door in the side of the bottle with a sharp knife. This should be 5 inches high and 3 inches wide. Leave one 5-inch side intact to work as a hinge for the door. This is the opening for adding materials and removing compost.
Punch holes every 4 to 5 inches in all directions with a nail or awl. These will provide aeration for the compost.
Add 3 inches of shredded paper or crumbled dry leaves. Top with finely chopped vegetable scraps, coffee grounds or eggshells. Moisten until damp but not soggy.
Close the door and secure with a piece of duct tape. Set the compost bin on a sunny window. Check daily for moisture content. If the material is too wet or appears slimy add more shredded newspaper and remove the cap to the bottle to improve aeration. If it is too dry, mist to moisten.
Roll the bottle on the floor or on a table each day to thoroughly mix and aerate the compost. Check weekly and record any changes observed. Compost will form in approximately 30 days as long as no new material is introduced.