Vermicomposting
This on-going, indoor activity involves live worms, and is usually
completed in three months.
Objective:
To develop an understanding of the role of living things in decomposition
and the nutrient cycle.
Materials:
1) Plastic 9”x12”x6” (or similar
sized) containers with covers (enough so that the children can work
in groups of 4 or less).
2) 25 Red worms (also called Red wrigglers) per
bin. These are the best kind of worms to use and may be purchased
from a variety of sources.
3) Several copies of newspaper, fruit or vegetable
scraps, leaves, water and soil
4) Starting Up Our Worm Bins worksheets.
Background:
Worm composting is a favorite activity for many children, and provides
students with a hands-on experience of the nutrient cycle in action.
Worms eat biodegradable material like paper, leaves and food scraps,
breaking them down into worm castings – a highly concentrated,
earthy smelling fertilizer. The children will harvest the castings
and use them in spring planting. A worm bin does require prep time
and maintenance, but is powerful and popular teaching tool.
Procedure:
Prior to the lesson, drill four or five holes into the plastic lids
of your bins. Good ventilation is required for aerobic decomposition
and is important for a healthy worm environment. Find a cool, dark
place to store the worm bins when they are not in use.
Discuss with your students how humans, plants and animals need nutrients and vitamins for growth and health. People and animals get nutrients from the food we eat. Plants remove nutrients from the soil in which they grow. How do the nutrients get into the soil in the first place? Nutrients are returned to the soil through the process of decomposition. Many different organisms are decomposers, but worms are very easy to study. (See Compost Critters on page ) Worms’ natural habitats are cool, dark, moist, underground tunnels. What will the class need to provide the worms so that they can survive indoors?
Prepare the worm bins by tearing the newspaper into one-inch wide strips. Rip the newspaper, leaves and food scraps into small pieces and place at the bottom of the bin. Spray well with water. Be careful to instruct the children not to use too much water – the mixture should be moist like a damp sponge. Toss in a handful of soil, and fluff the mixture like a salad to aerate. Be sure to cover the food with at least an inch of paper to prevent fruit flies.
Place about 25 worms onto the top of the newspaper. Instruct the children to observe what the worms do, and to try to resist touching them. (Worms breathe through their skin, and our oily hands can dry out or clog their skin. Try holding them on top of a moist piece of paper.) The worms will burrow down to the bottom of the bin to avoid the bright lights of the classroom. Cover the bins and use the Starting Up Our Worm Bins worksheets or your science journals to review.
Let the worm bins rest for a week or two by not adding any new food. Once the bins have rested, you may add food every 3-7 days. Add water when necessary to keep the bin moist.
