Many factors affect the type of soil on which living things depend. Soil can be hard or soft, the difference being the amount of space between the soil particles. To retain water and prevent erosion, soil needs to be somewhat compacted. However, if soil is too hard or compacted, water will run off before plants and animals are able to absorb it. The water and air levels become so low that the soil cannot support plant or animal life. Earthworms are particularly valuable to both maintaining good quality soil and enriching poor soil. Worms move through soft soil but ‘eat their way’ through harder soils. In doing so, the soil is aerated, allowing water and air to penetrate. They turn rotting plants and animals into vital fertilizer.
Earthworms are fascinating creatures. They move with tiny bristles along the sides of their body; they are photophobic (do not like light), have one brain and five hearts. Earthworms breathe when oxygen from water or the air passes through its skin. Worms must always live in a moist (not wet) environment or they will dry out or drown. Earthworms can produce their own weight in soil every 24 hours. Earthworms are both male and female. Red wigglers are the worms used in a vermi-composter or ‘worm bin’ because they do not mind ‘crowds’ of other worms. Earthworms do not do well in a vermi-composter because they like to burrow deep into the soil.
What You Need
- 2 large wide-mouth jars
- Garden trowel
- Plastic bags
- Netting or nylon stocking
- Water mister
- Black construction paper
- Cutting board
- Plastic knives
What to Do
1) For each worm habitat/worm jar, use five earthworms. Find earthworms on the ground after a rain shower in the evening. Alternatively, dig in a shaded, damp area of a garden. Take a good handful of soil with the worms and place them in a plastic bag.
2) Separate soil and worms. Layer the soil and sand alternately in one of the jars, making the soil layers thicker than the sand and filling it approximately 3/4 full. Finish with a layer of soil. Place the worms on this top layer. Have students draw and label a diagram showing the layers. Predict what they will see in a week.
3) Mist the soil (and worms) so that the soil is damp, not wet. Do this each day to keep the worm habitat moist.
4) Sprinkle in small pieces of food. Students could cut, with supervision, their leftover apple cores, banana peels, and other fruit/vegetable matter into small pieces. Do NOT add any materials with fat, such as buttered bread. Students could add decaying leaf matter from the schoolyard. Add ‘food’ once a week.
5) Cover the jar with netting or a piece of nylon stocking and keep in place with an elastic band. Secure black construction paper around the jar and put the jar in a spot that is dark and cool.
6) Allow the worms to adjust to their new habitat for a week or so. Disturb them only to mist them with water once a day.
7) At the end of the first week, remove the black paper and observe the layers. How accurate were the predictions? What has happened to the food scraps that were on the top of the soil?
8) Continue feeding and misting the worms for another 3 weeks. At the end of each week, have students observe what they see in the worm habitat.
9) At the end of a month, return the earthworms to where they were found. Remove the worms from the soil by placing the contents of the jar on a piece of plastic or sheet of newspaper. Carefully separate the worms. Keep some of the soil with the worms when returning them. Examine the soil.
10) Discuss with students the value of earthworms (aerating the soil, composting food scraps, adding ‘fertilizer’ to the soil).