1. BIN
2. BEDDING
3. FOOD
BIN
You can purchase commercially made bins or construct a bin from wood or plastic. A bin just needs to be 12”-18” deep, have a snug fitting lid and small holes in the bottom or sides for ventilation.
The ideal bin for classroom use and first time vermicomposters is an eighteen-gallon plastic tote, with a tight fitting lid (12" to 18" tall, 12" x 24" base). Drill air holes (no bigger than 1/4 inch) about halfway up on the sides of the bin.
OPTIONAL: To improve drainage, you can drill some holes in the bottom, but the bin will need to be placed on a tray to catch the vermicompost “tea”. This requires a bit more maintenance and if neglected could cause a nuisance in your classroom. If you don’t wish to drain the tea onto a tray, skip the bottom holes and collect any excess liquid from the bottom of your bin with a household turkey baster.
“Tea” is the term composters use for liquids that seep through compost picking up nutrients. Add this liquid to the water you use on your plants. In addition to nutrients, compost tea has shown to help plants be more resistant to disease.
Location, Location, Location
Worms prefer temperatures of 65-85 degrees F. Keep your worm bin indoors, out of the sun, in a quiet place, but not so isolated you or your class forget about them!
BEDDING
Worms love to live under moist paper or leaves. Bedding keeps the worms damp and also provides a high carbon material that the worms will break down.
Tear black and white newspapers into one-inch strips, fluff them up, and then moisten them so they are as damp as a wrung-out sponge. Fill your bin 3/4" full with this moist "bedding." Sprinkle bedding with a few handfuls of soil. Shredded leaves, paper, cardboard or straw are also good bedding materials.
FOOD
Worms eat about half their body weight a day! Feed 1 pound of worms about a cup of good scraps per day.
Food scraps include:
- Fruit and vegetable peelings, cores, seeds
- Breads, cereals, macaroni
- Coffee grounds, paper napkins
- NO Meats, Fat, or Dairy (worms will consume these foods, but you run the risk of a very smelly bin!)
Always bury food at least 4” down under the bedding. If the bin starts to smell or food isn't breaking down quickly, give your worms a break and feed them less food. Worms reproduce quickly, so they should be able to eat all your food if there's enough space and you increase the amount of food gradually. Hint: wrap food scraps in moistened newspaper. It reduces chances of developing fruit fly problems and adds fresh bedding at each feeding.
Feed in a pattern, choosing a spot and rotate around the bin. Rotation provides excellent observation activities. How many days until the worms find the new food? How long did it take them to completely eat all the food in one location?
As you feed the worms, take a look at the bin. Is the bedding drying out? Is the bedding too wet? Where are most of the worms hanging out? Do you see worm cocoons?
WORM ADOPTION
Your mini-ecosystem is ready. Where do you get the worms? For vermicomposting, the red wiggler or Eisenia fetida is the preferred species. These worms are “composter” worms, capable of processing large amounts of organic material. They thrive in the fluffy layer of leaves on the forest floor and in manure piles.
Soil dwellers, earthworms or night crawlers, thrive in earth tunnels and won’t be happy in the confined space of a vermicompost bin with the constant interruption of waste additions and observation by students.
Red wigglers can be purchased at local bait shops or via the Internet. The bait shop owner may call red wigglers manure worms or red hybrid. Start your bin with about a pound of worms (1,000-2,000 worms). When the worms arrive, just place them on top of the bedding. Leave the bin exposed to light as the worms work their way down in to the bedding. Once all the worms have left the surface, bury their first meal, cover with the lid and leave them alone for a week or so to allow them to get used to their new home. Then begin their regular feeding schedule.
MAINTENANCE
A healthy worm bin is a productive worm bin! Keep your worms healthy and happy by:
- Adding fresh bedding every 2-3 weeks, keeping a 4" to 6" layer of fresh bedding over the worms and food in your bin.
- Keep bedding moist, like a wrung-out sponge. Add dry bedding to absorb excess moisture.
- Harvest worm castings periodically every 3 - 6 months.
Worms, like all creatures prefer not to live in their own waste. After about 6 weeks, there will be noticeable changes in the bedding. It will be darker, and you will see more castings than bedding. It is time to harvest the vermicompost.
THE HARVEST
The simplest way to harvest the worm castings is to move the contents of your bin to one side. Fill the empty side with fresh damp bedding and a small handful of soil. Feed only on the new side and the worms will eventually migrate to the fresh side.
Use the castings by sprinkling 1/2 ” to 1” layer on top of indoor or outdoor plants or just dig the castings into your school garden soil.
St. Louis Area Teachers:
Gateway Greening has free resources to help set up classroom vermicomposting.
Call (314) 577-9484
Science Project Idea
Blend different portions of the harvested castings into potting mix and observe the difference in growth, size and production of plants.
Places to Buy a Bin or Worms:
www.squirmy-worms.com
www.vermitechnology.com
www.wormwoman.com
www.yelmworms.com
Worm Education Resources on the Web:
Worm Ranching in Missouri - www.dnr.state.mo.us/alpd/swmp/worms/wormlist.htm
Worm Digest – www.wormdigest.org
Herman the Worm – www.urbanext.uiuc.edu/worms/index.html
Worm Woman, Mary Appelhof- www.wormwoman.com
References:
Worms Eat My Garbage, 1982, Mary Appelhof, Flower Press, Kalamazoo, Ml,
Worm Digest, Issue #34, 2003
Learn With the Worm
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