Science project

Compost Sorting


  • Computer with internet access.
  • 8 large plastic containers (at least one foot deep and one foot in diameter)
  • Screwdriver
  • Packaged multipurpose potting soil (enough to fill containers)
  • Two kinds of seeds (tomatoes and nasturtiums are recommended)
  • Various composting materials
  • Basic gardening equipment (gloves, shovel, watering can, etc.)
  • Digital camera
  • Typical office/craft supplies (such as paper, pens & posterboard)


  1. Using the screwdriver, poke 3 holes in the bottom of each plastic container.
  2. Put a shovelful of potting soil in each container.
  3. Sort your compost into separate piles, using the plastic containers.  Put banana peels in two of them, coffee grounds in another two, etc.  Leave TWO containers with ONLY soil (no compost).
  4. Clearly label each container, and leave the containers outdoors.
  5. Check on (or add to) the containers regularly over the next two weeks.
  6. Fill each container nearly full with the potting soil, and mix well.
  7. Plant tomatoes (same kind, preferably from the same packet) in one of each type of compost.  Do the same with nasturtiums in the other containers.  Avoid overcrowding.
  8. Water plants regularly, maintaining them as indicated on the seed packets.
  9. Observe the differences.  Check ripe plants for color, texture, size and taste.
  10. Record all results.
  11. Interpret results in a detailed report.
  12. Show results visually using photos taken throughout the course of the experiment.
  13. Include plant samples in your science fair display.
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