Worms are eating my garbage!

 

Red worms

Grade:

6-8

Duration:

45 minutes

Objective:

To observe and understand the anatomy and life cycle of a redworm, and its importance in a garden ecosystem.

Big Idea:

Soil is formed by animals such as redworms, who live in food waste and digest it into soil.

Overview/Introduction:

The redworm is a worm that lives in food and plant waste, and helps digest it into rich soil. Their manure, or castings, is one of the most balanced fertilizers- full of nutrients and microorganisms. Using worms to make compost is called “vermicomposting.” When you provide the right type and amount of food scraps, it is some of the best compost made relatively quickly.

Redworms usually belong to one of two species: Eisenia fetida and Lumbricus Rebellus. E. fetida is the best for “vermicomposting. Redworms eat half their weight in food a day. They live 1 month to ten years. Foetida means foul-smelling, which refers to the worms anti-predator adaptation of producing an odor when handled. Redworms are hermaphroditic, although two are required to mate. When worms mate, they each secrete a cocoon, which contains several eggs. Worm eggs are yellow-to-brown in color, and each contains  one to three wormlets.

Worms can eat most food scraps, although meat, dairy, and a lot of cooked food should be avoided to reduce rodents and other pests. Citrus and onion scraps in large quantities should be avoided. Some people crush their egg shells to avoid getting a lot of shell pieces in the worm castings. However, egg shells make excellent worm “nurseries.”

Next, bedding is added to the food waste to provide moisture balance and retention, and to cover the food from flies. Bedding is the living medium for the worms, so it should be moist (something like a wrung-out sponge) and loose to enable the earthworms to breathe and to facilitate aerobic decomposition. Bedding materials can include materials high in carbon like shredded newspaper, dead leaves, sawdust, hay, cardboard, burlap coffee sacks and peat moss. We use horse manure that has aged for at 3-6 months because it is an excellent source of worms, and is locally available.

Materials:

  • worm compost that contains worms, eggs, and other soil life
  • hand lenses
  • containers to distribute compost

Vocabulary:

  • worm castings- the resulting compost the worms produce

Procedure:

  1. Introduce the idea of composting worms. Give a few facts.
  2. Explain that you are observing living creatures, and discuss appropriate handling.
  3. Tell the students they will be drawing pictures of the worms, and any other creatures they see as detailed as possible.
  4. Distribute small dishes containing worm castings, and hand lenses.
  5. Ask the students to find a  worm egg.  Ask, which end  is the head (anterior) and which the “tail” (posterieur)?
  6. Using the chalkboard, or projector, draw a detailed picture of the worms anatomy, and label the parts. Have students label their own drawing, and add any aspects they may have missed.
  7. Describe the reproduction of the worm.
  8. Describe the life cycle of the worm.

Assessment:

  • draw a compost food chain (or better yet- food web)  that includes the redworm.
  • draw the life cycle of the worm

Extensions:

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