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To begin vermicomposting, you'll need four things: A container for your worms, a supply of biodegradable bedding, a supply of food waste – and worms, of course. You'll find plenty of options and possibilities for each. You could, for instance, use an old dresser drawer for your bin. Or buy a deluxe, everything-but-the-kitchen-scraps vermicomposting system. Select the components that are easiest for you to obtain and maintain.
Wooden boxes, metal tubs and plastic basins work well as worm containers, provided they allow for good air circulation – the secret to an odor-free bin. The key criteria to consider in choosing or making a bin are:
Use 5/8" exterior grade plywood, with the exterior side facing inside, or scrap lumber. (Don't use treated wood.) Using screws, or nails with a spiral shape, will hold the box together under alternating wet and dry conditions. Any wooden box will last longer if it's allowed to dry thoroughly after harvest.
For a 2'x 2'x 10" box (suitable for two people, or up to four pounds of scraps per week)
For a 2'x 3'x 12" box (suitable for three to six people, or up to six pounds of scraps per week)
Assembly: Nail or screw the ends to the outside edges of the sides. Secure to bottom with five to seven nails or screws per side. Drill nine to 12 quarter-inch drainage holes evenly spaced across the bottom surface. The top is not attached; it just slides on or off.
Options: Nail 2"x2" pieces along the inside bottom edges for support. Attach four small wooden blocks to the bottom corners to raise the box off the ground – or secure four casters to the bottom corners for a box-on-wheels. Use gate hinges to attach the top to the box.
Besides giving worms a place to work and rest, bedding helps retain moisture in your box and keeps your scraps under wraps. Use light, fluffy biodegradable materials free from pesticides or chemicals. Try the following beddings in your bin.
Machine-shredded newsprint or computer paper: Recycling centers and pet shops may carry this material, or inquire at offices. Make sure no glossy or colored paper is used.
Hand-shredded newsprint or computer paper: Tear newspaper (without the color comics and glossy advertisements) into strips, the thinner the better. Thick strips mat down, dry out too fast and make it difficult to bury scraps.
Shredded cardboard: A good bedding material that holds moisture well. Check your recycling center for sources.
Leaves: Although leaves are a worm's natural habitat, they're not the best bedding for worm bins. Leaves tend to mat down, may harbor undesirable insects, or contain road salts and chemicals. If you do use leaves, gather them from a low-traffic area.
Enhance your bedding with the following additives and your worms will work double-time:
Peat moss absorbs excess moisture and breaks up heavy bedding. Try one-third to one-half peat moss in your bin.
Sterilized soil or sand contribute nutrients and grit to help worms digest food waste. Toss in a handful or two when preparing fresh bedding.
Crushed eggshells or ground limestone add grit and calcium; periodically sprinkle small amounts in the bin.
Now comes the fun part – choosing your worms. No garden-variety worms for you, friend. In fact, you'll want to avoid nightcrawlers and other garden worms, as they don't survive well in the confined conditions of a worm bin.
The best worms for vermicomposting are redworms. The redworm (Eisenia foetida or Lumbricus rubellus) goes by a number of names: red wiggler, manure worm, red hybrid, striped worm, fish worm – to list just a few. Whatever it's called, the redworm is the worm capable of reproducing quickly, in confinement, while chomping copious quantities of food waste.
How many worms should you start with?
Base the calculation on the average amount of food scraps your household produces per day. Use roughly two pounds of worms to one pound of daily scraps.If your household produces a half-pound of scraps daily, a one-pound package of worms should be enough. Or, guesstimate: use one pound of worms for a 2'x2' bin; two pounds of worms for a 2'x3' bin.
If you don't want to start with that many worms (one pound contains about 1,000 worms) get a smaller quantity and reduce the amount of food waste in the bin until the population increases. You won't have to wait long: Breeding worms can lay two or three cocoons per week that will hatch in 21 days, with each cocoon hatching two or three worms that will mature in 60 to 90 days.
Here we must call for calm: There's no need to stand guard at the basement door, broom in hand, to sweep back a worm invasion. These creatures understand the ecological concept of carrying capacity much better than humans do. A worm population eventually stabilizes at levels that can be supported by the food scraps added, and by the availability of room to move and breed.
You can buy worms from growers, bait shops, some garden centers, or through the mail. Prices range widely; expect to pay about $12 to $18 per pound (1998 prices). If you're reluctant to actually pay for worms, scrounge around an old leaf or manure pile, where you may find a few hardy redworms upon which to build your vermicomposting empire. Check with your local University of Wisconsin Extension office for names of worm growers who sell redworms by the pound. Bait stores typically sell them by the dozen or in small containers that tend to be more expensive.
Worms are true gourmands. They will eat just about anything, in quantities that would shame a sumo wrestler. That being said, there are still a few things you should know about what to feed these prodigious consumers:
Remember, you're in charge of the menu and the portion size. Be mindful of what your worms eat or ignore, and you'll soon know what you can put in the bin and what you should avoid.
After a long day of guiding students and faculty, Joan North, dean of the College of Professional Studies at the University of Wisconsin Stevens Point, goes home to learn from her worms. A search for a way to handle food waste in winter when the compost heap was in hibernation led her to vermiculture.
North started vermicomposting two years ago with half a coffee can of worms from a friend and a purchased plastic worm bin with a base and three stackable layers. Her biggest concern about moving several thousand red wigglers into the basement was breaking the news to her "ultra-neat" husband. "I practiced," she said. "'At last, the perfect pets!' And 'Honey, don't go into the basement because I have your Christmas presents down there.'"
Coir bedding (made from coconut husks) came with her bin, but coconuts being in short supply in central Wisconsin, Joan soon switched to machine-shredded newspaper. She checks her worms about once a week to make sure they have food. In winter, all the scraps from the family of two go to the worms. "In summer, they share half the leftovers with the outdoor compost bins," she says. "But I make sure that the worms get cantaloupe, their favorite."
For her own peace of mind, Joan keeps a lamp with a low-wattage bulb turned on near the bin. "It reassures me that the worms are staying put," she says. Though its unlikely the worms would ever escape, knowing there's a lid on the bin also helps Joan sleep at night.
"Vermicomposting was a lot easier, much cleaner, and less intrusive than I would have thought," she says. "While I have not gotten to know any of [my worms] personally, I do have a warm feeling about their collaboration with me to improve my garden and indoor plants. They do fine if I leave them for an extended vacation, and don't need shots or leave hair on the couch."
What better endorsement could a worm ask for?