Soda Bottle Composter
Activity Age Group: Grades 6-12 (With parental help for younger children)
Time: 45 minutes + weekly observation
- Use a homemade composter to observe composting in action, and better understand the composting process
Watch a short video before moving on to building your composter
What is decomposition?
Decomposition is the process in which organic substances are broken down.
What is composting?
Composting is a process of breaking down organic materials like banana peels, food scraps, dead leaves, or other materials into dirt. Composting is a great way to reduce the amount of food waste going into the landfill. This helps reduce harmful greenhouse gas emissions, and provides a nutrient rich soil to use for growing your own plants.
Empty 2 liter bottle
Scissors or knife
Pushpin / Nail / Tool to Poke Holes
Shredded Paper / Newspaper
Dirt (from outside)
Compostable Material (grass clippings, vegetable scraps, etc.)
Water (spray bottle if possible)
Small tray or plate
1. First, clean and remove the label of your 2 liter bottle.
2. Cut off the top part of the bottle where it starts to widen out. Save the top for later.
3. Using your tool to poke holes, make some holes in the bottom of the bottle for drainage, and a few small holes along the side for air flow
4. Add a thin layer of dirt to the bottom of the bottle
5. Moisten the soil using the spray bottle or by adding a small amount of water
6. Then add some shredded paper and dead leaves
7. Add another thin layer of dirt, just covering the leaves and paper
8. Moisten using your spray bottle
9. Add compostable material / vegetable scraps
10. Again add a small sprinkle of dirt
11. Put the bottle on your small plate or dish to help with drainage, and place your composter in a sunny spot
12. Use the inverted cut off top, or a small cloth as a top for your new composter
13. Keep it moist, and observe what happens over the next few weeks
Keep the compost moist by adding small amounts of water when necessary. You can use the cut off top as a funnel for adding water. Keep covered with your top or a small cloth.
Observations and Reflection Questions
Make a hypothesis. What do you think will happen over the next few weeks?
Record your observations. What happened to the food scraps as time went by? Did the amount of material in the bottle seem to change?
In what ways does composting help fight climate change?
In what ways could composting benefit your community?
Detroit does not have composting programs that are as accessible as some other cities. Why do you think that is? How could Detroit benefit from having one?
When what you have in your bottle is done decomposing, and looks like normal soil, you can plant seeds directly into it. Or add it to the soil of plants you already have to give them a boost of nutrients.