How to make an Earthworm Garden

Materials needed: Large jar with a lid
potting soil
Cornstarch
Apple peelings
A marker
2 or 3 earthworms which can be found by digging in your yard or a bait store

1. Make sure the jar is clean before you start.
2. Fill the jar with alternating layers of soil and cornstarch. The soil layers can be thicker than the cornstarch layers. Make sure you have at least four layers total.
3. Place a layer of apple peelings at the top.
4. On the outside of the jar use the marker to mark the boundaries between each layer.
5. Place the earthworms in the jar on top of all the layers.
6. Loosely replace the lid on the jar.
7. Observe the eathworm garden every day. Record what happens to the layers of soil, cornstarch, and apple peelings.
8. Make sure you water the earthworm garden every day to keep the soil moist.

*Over time the movement of the earthworms mixes up all the layers in the jar.

*The total height of the materials in the jar gets reduced over time.

Whats happening? When the earthworms burrow through the soil, they are looking for food to eat. The result of their movement is to create little tunnels through the soil. This is beneficial for plants, because the soil they grow in becomes better aerated by the worm tunnels. Earthworms also eat organic materials like the apple peelings in the experiment and then excrete worm castings that may be seen in your earthworm garden as a thick black layer of dirt. The worm cast material has a different makeup from the soil and is often denser and heavier than soil. This material also returns some nutrients form the apple peelings to soil faster than waiting for the apple peelings to decompose.

The purpose of the alternating layers of soil and cornstarch is to dramatically show how much motion a few little worms create. After a few weeks, the soil will appear almost homogeneous, except of course, for the black worm cast that is probably sitting near the top. Because the worm cast is denser than soil, it weighs everything down. The motion of the worms serves to pack the soil down, so the height of the worm garden reduces over time.