Worm Farming and Composting
In this biology lab, students will investigate the role that worms play in the decomposition of organic materials. Continuation of this lesson will show interdependence within an environment. The fertile soil created by the worms will create a rich environment for plant growth. The plant growth will attract insects, which in turn pollinate the plants and create fruit that will serve as compost for the cycle to continue.
- Students will learn vocabulary associated with decomposition and composting.
- Students will determine how to measure success in a composting pile.
- Students will record their observations and measure the success of the Red Worm Farm by tallying the number of worms produced over a period and their length.
Context for Use
This lab activity is appropriate for a primary classroom with appx. 20-25 students. I would allow 45 minutes for this activity. Today's lesson will set up the environment for the Red Worms. We will not be adding them for a couple of weeks. Now is a perfect time to order your Red Worms. The organic material that you will need may include (but is not limited to) apple cores, fruit/veggie peels, leafy materials (ends of carrots, lettuce, etc.)
Resource Type: Activities:Classroom Activity
Grade Level: Primary (K-2)
Theme: Teach the Earth:Teaching Environments:K12, Teach the Earth:Course Topics:Environmental Science, Soil
Description and Teaching Materials
The following chapter books would make good extensions to a worm theme: The Word Eater by Mary Amato, Katie Kazoo: Free the Worms by Nancy Krulik, How to Eat Fried Worms by Thomas Rockwell or Worms Eat My Garbage by Mary Appelhof
Lay out the following materials: candle with a lighter, clear tape, large and small poke (nail, diaper pin, safety pin, upholstery needle, etc.), Sharpie, safety blade or scissors, awl and hammer, one 2L bottle, a base from another 2L bottle or storage container that can be inverted for a cover on the 2L bottle and the lid can be used as a over flow tray, a brown paper bag or one 25 cm by 40 cm sheet of brown paper for a light block, 15-20 red worms, worm bedding: shredded newspaper, shredded leaves, peat moss and straw, worm food: organic leftovers from your kitchen/yard/plant material.
Bring out the worm bedding and worm food. Ask them what they think we can do with these items. When they are close, ask them what the other items have to do with it.
Observe Know Want to Know Hypothesize Learn Further investigating Questions
Record worm facts that we learned from the read alouds and previous knowledge.
Ask students if there is anything else they would like to know about worms. Jot these down under W (Want to Know).
1. Remove the label from the 2L bottle and cut it off about 10 cm below the neck (approximately a centimeter or two from where the width begins). You can either cut another base from a 2L bottle as a cover or use a storage container that can be inverted for a cover on the 2L bottle and the lid can be used as a over flow tray.
2. Heat a nail (be careful not to burn yourself) over a candle. Around the base, poke four, 5mm apart, drainage holes with the hot nail poke. After heating a nail, you will have an easier time puncturing the thicker plastic at the base of the 2L container. These will serve as drainage holes.
a. To create a nail poke: Cut a soft tree branch that is about 3 inches long and 1 inch wide. Cut the head off of a nail at a sharp angle. Poke the head-end of the nail into the soft core of the wood.
3. Heat a small poke over a candle. Poke two rows of eight, 3 mm apart, air holes with a small hot poke.
4. To create a dark, temporary casing tape a dark color of construction paper (that rises about 4 cm higher than the top of the 2L bottle) lose enough that you can easily pull it up. The only time to remove the casing is when you are observing or taking in measurements.
5. Cut about 2 pages of newsprint into .5 cm strips (perhaps sending them through a shredder will save some headaches). Cut these strips in half crosswise.
6. About ¾ cup of water should be added to the bedding. Fluff the bedding vigorously until the strips are well separated. Add a small handful of soil into the bedding (for the microorganisms that will help to break down the paper).
7. Fill the 2L bottle 2/3 full with the bedding/soil mix. The pH of the mix will need to be in the range of 6.5-8.5. If the mix is slightly too acidic, mix in some powdered lawn lime or finely crushed eggshells. The mix must be quite moist but not saturated.
8. Add the organic food to the top of the bedding. The organic material that you will need may include (but is not limited to) apple cores, fruit/veggie peels, leafy materials (ends of carrots, lettuce, etc.) Cover with 1-2 cm of the bedding.
9. Keep the temperature around 68-70 degrees.
10. Explain that the worms feed by eating the material and they breathe through their skin. For these reasons, the environment must be kept moist. The food should be no larger than 1-2 cm. Place the food on the bedding and cover it with about 1-2 cm of moist bedding.
a. Before adding more food, always check to see if the previous food is being eaten. Worms eat 2-3 times their mass of food every few days so it might be a better idea to underfeed them rather than overfeed them. If you add too much food, the environment will begin to smell sour and black fly larvae may become present. If need be, add more bedding to dilute the problem. The container should smell like freshly turned soil.
11. Continue with hypothesizing the role that worms play in soil. Ask the students how we can measure if our composting is a success. Ask them what we will need to do.
12. Teach students how to measure the pH. We will be measuring it every week or so, recording the data and plotting it on a graph.
a. Their wastes are referred to as castings and they fertilize the soil. As they move further into the earth, they move organic matter and leaves down and deep soil to the surface. They are the earth's natural aerators that move water and air to plant roots. You can expect the population to double within 3 months.
Teaching Notes and Tips
Based on an activities from:
Bottle Biology by Mrill Ingram p. 18-21.
Ugulano, Ronnie. "Vermicomposting-How to Raise Earthworms." Pontiac High School. 25 Jun 2009 .
Both of my resources say to order red worms. Due to the wide variety of earthworms, those in your yard may not be the best choice. Some worms prefer to burrow and be left alone, have slow reproduction rates, or release a stench.
I had a difficult time locating the red worms at local pet stores and bait shops. Your best bet is to order them online. While I am not sure, I am assuming that Red Wigglers and Red Worms are either the same thing or closely related.
A pinch of finely ground cornmeal will help with reproduction as will rabbit scat.
Fun extension activities:
- Using the soil to plant a flowering plant that will need to be pollinated by insects
- Obtaining and displaying a Venus Fly Trap to explain pollination
- Use different earthworms to see which does the best in the compost
- Will compost or soil provide a better environment for baby worms to be born?
Grade 2: Life Science: Interdependence in Living Systems- Natural systems have many components that interact to maintain the living system.