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Classroom Composting

Children will learn about farmers and create a classroom composting bin using worms.

Lesson Objective

Children will explore how farmers use compost to enrich their soil by creating and maintaining a worm composting bin.

Science

What You'll Need

Red Wiggler worms, 1-2 pounds (1 pound = approximately 1,000 worms)
Two 12-to-14-gallon plastic opaque storage containers with tight-fitting lids
Drill with a small drill bit
Potting soil - 2-4 cups
Food scraps from fruits, vegetables, grain products and coffee grounds (do not use dairy, meat, or oily items)
Colander
Large plastic bowl
Plastic spray bottle filled with water
Disposable gloves - a pair for each child and adult
Large amount of newspaper torn into ¼” strips
Plastic sand shovels or large plastic spoons - one for each child
Flashlight
Water

What To Do

Note: This lesson creates an ongoing activity. You will prepare the compost bin as one activity, care for the worms daily, and harvest the soil in about 3 months.

Begin a conversation about farmers. Discuss where they work and what they do. Explain that you will be exploring what farmers and gardeners do to create healthy, rich soil for their plants.
Have the students help you tear the newspaper into strips.
Place the strips of newspaper into the large plastic bowl and cover them with water.
Allow the newspaper strips to soak in the water for a few minutes.
Remove the newspaper strips from the bowl and place them in the colander to drain. When done, they should be damp but not dripping with water.
While the newspaper is draining, drill 10-12 air holes (about one-third of the way down from the top edge) all the way around the containers.
Drill holes for drainage in the bottom of one of the bins.
Place the bin with the holes in the bottom inside the other bin.
Invite the children to fill the inner bin about one-third full with the wet newspaper.
Let the children use the sand shovels to scoop the potting soil into the bin.
For children who are comfortable, let them add the worms and food scraps. Every pound of worms will need one pound of food per week.
Take turns gently mixing the contents. Try to make sure all the food is buried under the dirt so you will not attract fruit flies.
Cover the whole mixture with about an inch of dry, torn newspaper.
Use the water bottle to spray the top layer of newspaper. Moisten the paper, but do not soak it.
The container should be kept in an environment with a temperature between 55 and 77 degrees.
Caring for your worms, see Lesson Tips (below).
Harvesting your composted soil: See the section below titled “Harvesting Your Composted Soil” for steps on how to harvest the soil.

Guiding Student Inquiry

Have you ever visited a farm?
What kind of things can you find on a farm?
Do you know what the farmer does at the farm?
What kinds of plants might be on a farm?
How do farmers take care of their plants?
Show the children one of the worms. “Let’s look at this (show them a worm), have you ever seen one of these before?”
Where did you see it? What was it doing?
Do you know what this is?
Tell me about it. What does it look like? How does it feel?
Will it hurt us or is it gentle? How does it eat?
How do farmers help our community?

Explore, Extend & Integrate

Provide opportunities for the children to observe and document what they see as they create and use the compost bin. Leave clipboards and crayons or markers near the composting bin so the children can draw and “write” their observations.
Create interactive charts and graphs where the children can record important information, such as when or what the worms have been fed.
Add tasks, such as collecting food scraps or spraying the compost bin with moisture, to your job chart.
Collect worms from the playground, place them in your discovery center, and let the children compare them to the worms in the compost bin (release the worms back to the playground when you are done).

Check for Children’s Understanding

Can the children talk about what the worms did with the paper and food?
Were the children able to recognize the connection between the food scraps, worms, and compost?
Did the children understand that farmers “feed” their plants with compost?

Harvesting your Composted Soil

You will know your compost is ready for harvesting when there is more compost and less bedding. This typically takes about 3 months.
Spread a thick plastic tablecloth on the ground outside. If you are doing this inside, lay the tablecloth in a plastic baby pool to keep the compost contained.
Anyone handling the compost should put on disposable gloves.
Remove the mixture from the composting bin and mound it in a pile on the tablecloth.
Shine the flashlight on the pile. The light will drive the worms to the bottom.
Now harvest the compost. Small lemon-shaped pieces of soil are actually worm cocoons; be sure to add these along with the worms back into the worm bin.
Return the worms and some of the compost to the original bin. Mix them with fresh potting soil, newspaper, and water, as if you were starting over.
Use the collected composted soil. The children can mix it with potting soil and use it to plant seeds or bulbs in pots or create an outdoor garden of flowers or vegetables.

Resources

Did You Know?

Worms can be used to make compost in the classroom. Worms are natural decomposers, breaking down organic material into smaller pieces through digestion. Worm composting takes up much less space than leaf composting. Worms love paper and break it down very quickly; worms also create rich soil.

Composting is a process that occurs when tiny, microscopic organisms break down old plant and animal tissues and recycle them to make new, healthy soil. About 30% of all the garbage in the United States is made up of waste from food and yards. Composting is a great way to recycle household and lawn waste. This waste includes grass clippings, egg shells, and orange peels.

Do not use “regular” worms from the soil in your yard or playground. Red wiggler worms work best in composting containers. Composting worms, such as red wigglers, can be purchased from garden supply stores or through the Internet. Fall is a good time to start worm composting. It takes a few months for the worms to create a good rich soil. When the compost is ready to harvest, it will be just in time for spring planting.

Vocabulary: Child-Friendly Definitions

farmer - a farmer is a person who works on a farm and raises or takes care of the plants and animals.
worm - an animal with a long, thin, round or flat body with no legs; worms live in water or on land.
compost - compost is a mixture of decaying or rotting things like leaves and vegetables. Compost is used to improve gardening soil.
soil - dirt; the top layer of the Earth. It is usually brown and things grow in it.
harvest - when we harvest, we gather or pick ripe vegetables and fruits.
decompose - decompose means to break down, decay, or rot. Vegetables and fruits decompose when they are composted.

Lesson Tips

Keep an eye on your worms. If you see worms scaling the walls of the bin, the temperature inside may be too hot. Leave the lid off and stir often. If the worms are still climbing the bin with the top off, then the bin may be too wet. If this is the case, add more torn, dry newspaper and be sure to leave the lid off for at least part of the day. Feed weekly, 1 pound of food scraps for each pound of worms.
Do not feed your worms citrus skins (orange, lemon and grapefruit). They contain oils that can be detrimental to the worms.
Remind the children not to touch their faces when handling the worms or the compost and to wash their hands each time they are finished.
Many newspapers use ink that leaves residue on your hands. The ink can stain clothing. You might want the children to wear smocks during this activity.
Some children and adults are sensitive to the ink on newspapers and may sneeze, cough, or have watery eyes. Try to limit their contact with the newspaper.

Books

An Earthworm’s Life by John Himmelman
Wiggling Worms at Work by Wendy Pfeffer
Garbage Helps Our Garden Grow: A Compost Story by Linda Glaser
Diary of a Worm by Doreen Cronin

Home School Resources

Home educators: use these printable lesson PDFs to teach this lesson to your home schoolers. They're available in English and Spanish.

Home/School Connections

Las Conexiones a la Casa

While we believe that the books and resources recommended may be of value to you, keep in mind that these are suggestions only and you must do your own due diligence to determine whether the materials are appropriate and suitable for your use. PNC has no sponsorship or endorsement agreement with the authors or publishers of the materials listed.

Content Provided By

Visit The Delaware Museum of Nature & Science

Common Core State Standards Initiative – These lessons are aligned with the Common Core State Standards ("CCSS"). The CCSS provide a consistent, clear understanding of the concepts and skills children are expected to learn and guide teachers to provide their students with opportunities to gain these important skills and foundational knowledge^[1]. Visit the CCSS

There are currently no Common Core Standards for pre-k, but these lessons are aligned as closely as possible to capture the requirements and meet the goals of Common Core Standards. However, these lessons were neither reviewed or approved by the National Governors Association Center for Best Practices or the Council of Chief State School Officers, which together are the owners and developers of the Common Core State Standards.

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