by Jen Fong and Paula Hewitt
(Adapted from Cornell Cooperative Extension)
1. Worms can eat their weight in soil each day. Over 1 million worms may be present in one acre of soil, and these worms can produce 700 pounds of castings each day. Two thousand red worms in a worm bin can produce 7 pounds of castings in one month.
Ask children to estimate how much food waste they produce each day. What happens to it? What ways can food waste and other waste be recycled?
2. Worms do not have teeth. Their food is softened by moisture or by microorganisms which break it down. Food is further broken down in the worms' gizzard, which contains hard particles and muscles which grind ingested food.
Observe which food wastes decompose the fastest, and try to explain why. What are your worms' favorite foods? Do worms like dry or wet garbage best? Why?
3. Worms are not the only living organisms in the worm bin. All sorts of microorganisms (in fact, billions of them) live in a worm bin. These microorganisms are introduced to the bin from the skin of the worm and from soil added to the bedding. Added garbage introduces more microorganisms, as do fungal and bacterial spores that land in the bin from the air.
Are other creatures besides worms present in your classroom worm bin? Look for composting critters outside, in piles of decaying leaves. Where else can you find them?
4. Worms do not have eyes, but they can sense light, especially at their front end. They move away from light, and will become paralyzed if exposed to light for too long (approximately one hour). If a worm's skin dries out, it will die.
Observe worms' reactions to light. Why do worms stay inside your covered worm bin?
5. While worms need moisture to survive, too much moisture will kill them. Have you ever noticed worms on the sidewalk after a rainstorm? This happens because the worms' homes in the soil got flooded, and the worms came to the surface in search of less soggy conditions. Once on the pavement, worms often get disoriented and cannot find their way back to the soil. They then dry up and die when the sun comes out.
After a heavy rainstorm, go out on a worm hunt. What should you do when you see worms on the pavement? (Stepping on them is not the right answer!) Be a worm rescuer- put them back in the soil where they belong and can survive. Why do we want worms to survive?
6. Worms are hermaphrodites; each worm has both male and female organs. Worms mate by joining their clitella (the swollen area near the head of a mature worm) and exchanging sperm. Then each worm forms an egg capsule in its clitellum; after 7-10 days, this is shed into the castings. Egg capsules are lemon-shaped and about the size of a match head. After 14-21 days baby worms hatch from the eggs. One to five worms emerge from each egg. In 60-90 days, the young worms are mature.
Try to find mature worms, young worms and worm eggs in your worm bin.
7. Worms can live as long as four years. When worms die in the bin, their bodies decompose and are recycled by other worms, along with the food scraps. Worm castings are toxic to live worms. After all the food scraps in a bin are recycled, the worms will eat their own castings which will poison them.
Why should a worm bin be harvested every few months? Harvest your worm bin when it is filled with compost.
8. Contrary to popular belief, worms cannot reproduce by being cut into small pieces. However, they do have amazing healing powers. If you cut a worm in half, both sides will continue wiggling. The portion with the head may grow a new tail if the cut is after the segments that contain vital organs. The tail portion will continue to wiggle until the nerve cells die. The tail end will not grow a new head.
What other animals can regenerate parts of their bodies?
9. Worm castings contain nitrogen and other nutrients necessary for plant growth. When added to soil, worm compost increases nutrient availability and improves soil structure and drainage.
Transplant a few plants, seedlings or seeds in a potting mix with worm compost added, and transplant other plants or seeds into pure potting mix. Observe what plants grow the best, and try to explain why.
10. In addition to making soil, worms are natural soil tillers. They mix layers of soil while producing tunnels in the soil to help air and water to reach plant roots. Tiny feeler-like bristles, called setae, on the bottom of worms help worms to move through the soil.
Put worms into a glass container with soil, and watch them make tunnels in the soil. Put layers of different types of soil into the glass container, and watch the worms mix the soil.
11. There are over 3000 species of earthworms in the world. Red worms (Eisenia foetida) are best for a worm bin because they are natural surface feeders that do not burrow as nightcrawlers do. Thus, living in a worm bin is not as confining to red worms as it would be to nightcrawlers. Red worms for worm composting can be purchased from worm farms. Composting worms are usually sold by the pound.
Look for worms in garden soil, vacant lots, etc. How many kinds of worms did you find? Where did you find the most worms? Research worms from around the world. Where in the world kind you find worms several feet long?
12. Many people mistakenly believe that garbage sent to landfills decomposes quickly, like it does in a worm bin or compost pile. However, this is not at all true because the key ingredients of air and moisture are missing in a landfill environment. Additionally, worms and other important decomposers can not live or function in such conditions.
Put some worm food in an air tight bag. Compare what happens to this food to what happens to food in a worm bin.
©Jen Fong and Paula Hewitt
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Cornell Waste Management Institute © 1996
Department of Crop and Soil Sciences
Bradfield Hall, Cornell University
Ithaca, NY 14853