Teacher's Guide To Working With Worms

Having a worm bin in your classroom can provide several exciting, hands-on learning experiences. Here are some recommendations and reminders to help you maintain a problem-free environment for the latest additions to your classroom. Enjoy!

Worm Bins have certain requirements

1. Worms
   Red wigglers are recommended because they can most quickly and efficiently process food waste into vermicompost.
2. Bedding
   Shredded newspaper (in strips about 1" wide) is adequate. The bin will require more bedding as time progresses. A general rule of thumb is to keep the bin about 3/4 full with bedding. Remember to wet it by squeezing out excess moisture until it is as damp as a sponge.
3. Vegetative food waste
   • YES! include greens, vegetables, fruits (except avoid excessive citrus), coffee grounds. and filters, egg shells, tea bags.
   • NO!! do NOT include meat, fat, or grease, dairy products, bread and grain, oils, or bones.
4. Air
   Worms, like humans, require a supply of air to live. Your worm bins need to include air holes to provide ample air circulation. Be careful not to block the passage of air through the air holes.
5. Water
   Once the worm bin gets under way a proper balance of moisture will be provided as a byproduct of the decomposition process. In very hot weather you may need to lightly add water if the bedding becomes too dry.

The worm bin is an active ecosystem, so expect to encounter several other animals living in the bin besides red wigglers. You may observe the presence of mites, beetles, sowbugs, white worms, and springtails. All of these animals play an important role in your system and will not harm the red wigglers or vermicomposting process.

Feeding your worm bin

How much is too much?
Plan on one square foot of surface for each pound of food waste per week. The worm to garbage ratio is 2:1. For every pound of worms, 1/2 pound of food waste should be added.

Food waste the size of an apple core is ideal
The smaller the pieces of food waste the more surface area is created on which the worms and bacteria may feed.

Rotate
It is essential to rotate the location of newly buried food waste (remember to cover with bedding!) The following diagram shows how burial spots can be located over the span of eight weeks.

Have your students record the amount and type of food placed in the bin along with the location. You can observe the varying decomposition rates of the different materials in each location. Measure, record, and graph the observations.

Troubleshooting

Smell
Odor is a sign of anaerobic conditions arising from excessive feeding, poor air circulation, or over-watering.

• You may be overfeeding your bin. Too much vegetative waste overloads the system and increases the chance of molds and odor.
• Stop feeding the bin vegetative waste for a period of time. Also make sure that no meat, fat, grease, or dairy has been placed in the bin.
• It may be helpful to aerate the bin by gently stirring it with a hand rake or by simply adding more, dry shredded newspaper.
• Once the smell has subsided, resume feeding the worms. Pay special attention to providing the proper ratio of carbon to nitrogen (newspaper to food) to ensure healthy conditions in your bin.

Fruit flies
These tiny little flies are more of a nuisance to your classroom than to the bin. The type of food placed in your bin seems to be a factor in a sudden population explosion of these insects.

• First, remember that it is essential that all food waste placed in the bin be covered with one to two inches of bedding. Adequate topping of the food waste with shredded newspaper will help reduce insect presence.
• Laying a sheet of plastic or cardboard over the bedding can also help reduce insect numbers.
• Target the reduction of citrus fruits going into your bin. Eliminating these fruits from your system often helps to reduce the fruit fly presence.
• If the reduction of citrus fruits proves insubstantial, reduce or eliminate all fruit from your worm bin for a period of time.

Remember...

• Be careful not to place your worm bin in an area where it will experience temperature extremes. The ideal temperature for the bin is 60 - 80 degrees Fahrenheit.
• Newspaper has a tendency to get matted together. Make sure strips of newspaper are fluffed up to provide shelter for the worms and allow air to circulate.

Once you have harvested the vermicompost from your classroom worm bin use it to enhance the soil for plantings in your classroom or school garden. The ideal potting medium includes a ratio of 1 part vermicompost, 1 part soil, to 1 part vermiculite.

Did you know??

• A worm can eat half its weight in food each day
• If you cut a worm in half it will probably not grow new parts

The Clackamas County Recycling Partnership can provide schools with a variety of resources, waste reduction education, and technical assistance. The CCRP also coordinates the Oregon Green Schools Recognition Program for Clackamas County. The Oregon Green Schools Program recognizes schools for successful waste reduction achievements. Please contact us if you would like information on any of these services.

Do you still have questions? Contact Waste Reduction Education Coordinator Laurel Bates at 503-742-4454 or lbates@clackamas.us.