Worms Can Recycle Your Garbage
Agriculturual Engineering Specialist
Published by: North Carolina Cooperative Extension
Publication Number: AG 473-18
Last Electronic Revision: March 1996 (JWM)
North Carolina's estimated 420,000 tons offood waste are buried or burned each
year at considerablefinancial and environmental cost. Instead of discarding your
food scraps, you can recycle them with the help of worms. Vermicomposting
(worm composting) turns many types of kitchen waste into a nutritious soilfor
plants. When worm compost is added to soil, it boosts the nutrients available to
plants and enhances soil structure and drainage.
Using worms to decompose food waste
offers several advantages:
- It reduces household garbage disposal costs;
- It produces less odor and attracts
fewer pests than putting food
wastes into a garbage container;
- It saves the water and electricity
that kitchen sink garbage disposal
- It produces a free, high-quality soil
- It requires little space, labor, or
- It spawns free worms for fishing.
Equipment and Supplies
The materials needed to start a
vermicomposting system are simple and
inexpensive. All you will need are a
worm bin, bedding, water, worms, and
your food scraps.
Wonn Bin. A suitable bin can be constructed of untreated, nonaromatic
wood, or a plastic container can be purchased. If a plastic container is used, it
should be thoroughly washed and rinsed
before worms and bedding are added.
The bin size depends on the amount of
food waste produced by your household.
For two people (producing approximately 31/2 pounds of food scraps per
week), a box 2 feet wide, 2 feet long, and
8 inches deep should be adequate. A 2-foot-by-3-foot box is suitable for four to
six people (about 6 pounds of waste per
week). Redworms (the type used for
vermicomposting) thrive in moist bedding in a bin with air holes on all sides.
For aeration and drainage, drill nine
l/2-inch holes in the bottom of the 2-foot-by-2-foot
bin or 12 holes in the 2-foot-by-3-foot bin. Place a plastic tray under the
worm bin to collect any moisture that
may seep out. Keep a lid on the bin, as
worms like to work in the dark. Locate
the worm bin where the temperature
remains between 55° and 77°F. (An indoor location is preferable.)
Bedding. The worms need bedding
material in which to burrow and to bury
the garbage. It should be a nontoxic,
fluffy material that holds moisture and
allows air to circulate. Suitable materials
include shredded paper (such as black-and-white
newspapers, paper bags, computer paper, or cardboard); composted animal manure
(cow, horse, or rabbit); decaying leaves; or peat moss
(which increases moisture retention). Add two handfuls of soil to supply roughage for the worms. Adding
crushed eggshells provides not only roughage but also
calcium for the worms, and it lowers acidity in the bin.
About 4 to 6 pounds of bedding is needed for a 2-foot-by-2-foot bin (for two people), and 9 to 14 pounds of
bedding should be used in a 2-foot-by-3-foot bin (for
four to six people).
Water. To keep bedding moist, add 3 pints of water
for each pound of bedding. You will need about 1 l/2 to
21/4 gallons of water for 4 to 6 pounds of bedding.
Worms. It is important to get the type of worms
that will thrive in a worm bin. Only redworms or
"wigglers" (Eiseniafoetida) should be used (do not use
nightcrawlers or other types of worms). Worms can be
obtained from bait shops, nurseries, or by mail from
commercial worm growers; the commercial growers
are the most reliable source. Add 1 pound of worms to
the 2-foot-by-2-foot bin or 2 pounds of worms to the 2-foot-by-3-foot bin.
Food Scraps. Feed your worms any nonmeat organic waste such as vegetables, fruits, eggshells, tea
bags, coffee grounds, paper coffee filters, and shredded garden waste. Worms especially like cantaloupe,
watermelon, and pumpkin. Do not add meat scraps
and bones, greasy foods, fat, tobacco, or pet waste.
Starting the Process
To start your vermicomposting system, first select a
location for your worm bin, such as the basement,
garage, or kitchen. Soak the bedding in a bucket overnight
so that it is moist but not soggy. Place the bedding evenly into the worm bin and gently add the
worms to the surface of the bedding. Keep the bin lid
off for 1 to 2 hours so that the worms will move away
from the light and burrow into the bedding.
Once the worms have settled into their new home,
add food scraps. It is best to dig a hole in the bedding,
place waste in the hole, and cover it with about 1 inch
of bedding. Bury food scraps in a different area of the
bin each time. Worms may be fed any time of the day.
Do not worry if you must leave for a few days, as the
worms can be fed as seldom as once a week.
Harvesting the Worms and Compost
In three to four months, your worms will have turned
the food scraps and bedding into a dark, rich, soil-like
material called vermicompost. This material can be
mixed into the soil in your garden and around your
trees and yard plants. It can also be added to potting
soil for your houseplants.
To harvest the vermicompost, push all of the bedding to one side of your worm bin. Place new, moist
bedding (half of the original amount of bedding) on
the empty side, and add food scraps only to the new
bedding. Within about four weeks, all of the worms
will have moved into the new bedding and left finished compost on the old bedding side. Remove the
compost and replace it with new bedding (half of the
original amount). Now you can begin adding food
scraps to both sides of the bin again. Repeat this process every three to five months.
Managing Your Worm Bin
Here are some other things you should know about
your vermicomposting system.
- If too much food is added, the system can become
overloaded and cause an odor. The odor will dissipate if you stop adding food until the worms
- Providing adequate oxygen and not too much
moisture also minimizes odors.
- If fruit peels are buried completely, fruit flies will
not be attracted to the bin.
- When worms reproduce, they create matchhead-sized cocoons. Do not disturb them.
- Do not use your worm bin as a cat litter box, and
do not add dog or human manure to the bin.
- Do not be surprised to see other creatures in your
worm bin, as they help break down the organic
material. Most of the organisms will be too small
to see, but you may spot white worms, springtails,
pill bugs, molds, mites, and fruit flies.
Vermicomposting can take place wherever food scraps
are generated or delivered. Worm composting bins can
be found in classrooms, apartments, offices, and other
commercial locations. Large-scale worm farms are
found in some states, including California, Rhode Island, and Oregon. Worms even compost the food
waste produced at the Seattle Kingdome stadium.
Classrooms and outdoor centers are especially nice
settings for worm composting. Children of all ages
enjoy classroom activities involving worms. Curricular
materials for grades 4 through 8 may be found in a
232-page book entitled Worms Eat Our Garbage. Activities
in the book can be used in a multitude of disciplines, including science, mathematics, geography,
language arts (vocabulary, poetry, and prose), and
Sources of Additional Information and
Flowerfield Enterprises, 10332 Shaver Road,
Kalamazoo, Michigan 49002; telephone (616) 327-
0108. Offers worms, bedding, bins, and books, including Worms Eat My Garbage (a guide to setting up
and maintaining a worm composting system) and
Worms Eat Our Garbage (a curriculum guide for school
and outdoor centers).
Carolina Biological Supply, 2700 York Road,
Burlington, North Carolina 27215; telephone (800)
334-5551. Offers worms, bedding, and bins.
The Worm Concern, 580 Erbes Road, Thousand Oaks,
California 91362; telephone (800) 854-1244 or (805)
520-1150. Sells vermicompost, worms, bedding, bins,
books, plants, mulch, natural pest predators, and
Local Information Resources
North Carolina Cooperative Extension Service
Contact your county Cooperative Extension Center
North Carolina Office of Waste Reduction
P.O. Box 27687
Raleigh, NC 27611-7687
Telephone (919) 571-4100 or (800) 763-0136
Distributed in furtherance of the Acts of Congress of May 8 and June 30,
1914. Employment and program opportunities are offered to all people
regardless of race, color, national origin, sex, age, or disability. North
Carolina State University, North Carolina A&T State University, U.S.
Department of Agriculture, and local governments cooperating.