Information Leaflet #7
Vermicomposting: Composting with Worms
Worms can turn kitchen waste into a nutrient-rich soil conditioner
called vermicompost. Vermicompost is a mixture of worm castings
(droppings) and decomposed organic material. This small-scale form
of composting is ideal for apartment-dwellers and those who lack
space for an outdoor compost bin. Vermicomposting also extends the
composting season, an important consideration in our northern
climate. Worms kept indoors will continue to consume waste when
outside compost piles are frozen.
What You Will Need
The size of the container and the number of worms needed depends on
the amount of waste added. Try to get a rough estimate of the
amount of kitchen waste you produce in a week. A worm bin should be
about a foot deep and provide one square foot of surface area per
pound of waste.
Number of People Quantity of worms Bin size
1 or 2 1 lb 1 ft x 1.5 ft x 2 ft
2 or 3 1 lb 1 ft x 2ft x 2 ft
4 or 6 2 – 3 lb 1ft x 2ft x 3.5 ft
Plastic bins are suitable for a small number of worms but they may
require drainage holes. Wooden boxes are more absorbent and provide
Worms like a dark, moist environment. Cover your bin with a piece
of moistened burlap sacking and a sturdy lid.
The location of your bin is important to the success of the
project. A worm box makes an excellent addition to any kitchen,
basement, laundry room, shed, or garage. Outdoor bins should have a
lid and the worms need to be protected from extreme temperatures.
Select a shady location and move them indoors when winter comes. We
have noticed at MUN Botanical Garden that they do not like drafts
or cold temperatures and will actually migrate from the bin if they
are not comfortable. Worms are cold-blooded creatures are do
require some external heat to stay active. However, they should
never be placed directly near a heat source.
Red wigglers (Eisenia fetida and Lumbricus rubellus) are the best
worms for vermicomposting. They are much smaller and thinner than
earthworms and they don't seem to mind being kept in captivity.
Some people call them "redworms", "manure worms", "brandling
worms", or "trouters".
The red wigglers used at MUN Botanical Garden were generously
donated by Bill Glynn of Trouters Special Worm Farm in Bay Bulls.
Mr. Glynn has been raising worms and vermicomposting in
Newfoundland for many years. He sells worms, bedding, castings and
containers to the public. He is also an endless source of knowledge
and advice. At time of printing, there are no other worm farms in
Your worms will eat everything you put in the bin, including their
bedding! Use a variety of materials to provide them with more
nutrition. The following materials make an ideal bedding:
Shredded fall leaves
Dried grass clippings
Add a couple of handfuls of sand or soil to provide your worms with
grit for their digestive systems.
4. Food Waste
Feed your worms the same kitchen waste that you would add to your
outside compost heap. Bury wastes and vary the location of each
deposit to avoid overloading your bin. Finely chopped food will be
broken down more quickly than large chunks. Do not add meat, fish,
dairy products, or fats. Citrus fruit peels take a long time to
break down so add them sparingly. For more information on what to
compost, please refer to Compost Information Leaflet #2 of this
Red wigglers will convert waste into vermicompost within a few
months. The compost is ready to be harvested when there's little
original bedding left and the food scraps have been converted to
brown and earthy-looking worm castings.
Move the finished compost to one side of the bin and place new
bedding in the space created. Bury fresh food waste in the new
bedding. Your worms will gradually migrate to the new food and
fresh bedding, leaving the finished compost to be skimmed off.
Sprinkle into a seed row when planting
When transplanting, add a handful of vermicompost to the hole.
Use as a top-dressing or mulch around the base of plants
Mix half and half with potting soil for your houseplants.
Vermicompost Potting Mix Recipe
part worm castings for nutrients
part peat moss to help hold moisture
part perlite to aerate the soil
part sand or garden soil for bulk
Will it smell?
Not if air can circulate through the layers.
Drill holes in plastic bins and line with mesh
Raise the bin above the floor
Choose bedding that will not mat down
(newspaper tends to get soggy)
Turn the bedding every two weeks
It is best to compost only recommended wastes.
Dairy products, fats, and meats can cause unpleasant odors.
How can I avoid fruit flies?
Fruit flies can become a problem if a high amount of fruit waste is
put in the compost. The problem may be compounded if the lid is
opened quite frequently as in a classroom setting. The following
procedures may prevent this problem:
Bury all food waste
Avoid adding too much slow-decomposing fruit waste like citrus
Don't overload your bin
Keep the surface of the compost covered with a piece of burlap and
To Solve a Fruit Fly Problem:
Place a flypaper coil next to the box or spray the surface with a
fine mist of Safers soap every second day for one week.
Try a fruit fly trap: Cut a plastic pop bottle in half and fill the
bottom with an inch of vinegar. Fit the top of the bottle upside
down into the bottom so that the neck is just above the
Compost versus Fertilizer
Plants need water, sunlight, and nutrients to grow. Three important
nutrients are nitrogen (N), phosphorous (P), and potassium (K).
Nitrogen (N) is used to make protein and chlorophyll by the plant.
It is important for good leaf development and vegetative growth.
Too little nitrogen causes slow, spindly growth. Leaves may turn
yellow due to lack of chlorophyll – the green pigment which
helps plants make food.
Phosphorous (P) is vital for the growth of root and stem systems.
When little of this nutrient is present in the soil, seedlings may
not become well established.
Potassium (K) plays an important role in the plant's metabolism. It
is involved in resistance to chill, drought, and disease. Lack of
potassium may result in brown, scorched patches on leaves. Leaves
may also roll inwards or downwards
Compost also provides nutrients, but usually at lower
concentrations than chemical fertilizers.
Compost does, however, release nutrients to plants over the
long-term, whereas chemical fertilizers are a short-term solution
and must be reapplied regularly over the growing season. Extensive
use of chemical fertilizers has also been linked to environmental
degradation. Excess fertilizer can leach out during rain and end up
in local rivers and ponds. Fertilization does not replace the value
of soil improvement, which involves adding organic material.
Worms: A Gardener's Best Friends
Worms dig tunnels which allow air and water to penetrate the soil
and improve root development. They are also living miniature
compost factories! During digestion they secrete chemicals which
free nutrients necessary for plant growth. Worm castings (or
droppings) contain five to eleven times more available nitrogen,
phosphorous, and potassium than the soil they ate to make the
A Word about Good Worm Stewardship…
By removing worms from their natural habitat, you're taking
responsibility for their care and well-being. Worms, like any
creature kept in captivity, will die if neglected. Before starting
your vermicomposting project, please ensure that everyone involved
is ready to be a good worm steward!
The Biology of Worms:
Worms can live up to about a year in a worm bin. Because the worm's
body is about 90 percent water, if a worm dies in the worm bin, it
will shrivel up and become part of the compost rather quickly.
Worms are hermaphrodites, which means they are both male and female
at the same time. However, worms still need to mate. Two worms
attach to each other for a few minutes, and several days later,
both produce a cocoon or egg case. The cocoon eventually separates
from the worm. Inside the cocoon, two to five baby worms may be
found. The baby worms live in the egg case for at least three
weeks, sometimes longer depending on the surrounding conditions. In
the winter time, for example, baby worms may stay in the cocoon for
many weeks until the temperature warms up again. When the baby
worms eventually crawl out, they are the thickness of a piece of
thread and about 1 centimeter long. Usually the worm appears white,
as they have not yet developed enough blood (pigmentation) to be
seen. In two or three months, worms are mature.
True or False?
Worms breathe through their skin? True
Cutting a worm in half will make two worms False
(Cutting a worm in two will eventually kill it.)
Red wigglers can eat their weight in food every day True
Worms have teeth False
Worms are blind True
(Worms don't have eyes and so they cannot see. They are,
sensitive to bright light – that's why they burrow into the
How long does a worm live?
In the wild, most worms live for a year. Worms must survive cold
weather, droughts, and predators. In captivity, some worms have
lived for as long as four and a half years!
What does the early bird have in common with the worm?
Both birds and worms have a muscular gizzard which contains small
particles of grit. When the muscles of the gizzard contract, these
hard particles help grind food into smaller bits, which are easier
to digest. Worms in captivity need to be provided with a handful of
sand or grit to help them digest your kitchen waste.
Have you ever wondered why worms are slimy?
Worms need air to survive, but unlike people, they don't have
lungs. Instead they breathe through their skin! Oxygen enters their
bodies by dissolving in the moist layer that covers them. If a worm
dries out, it can't breath.
A Note To Educators:
Interested in incorporating vermicomposting into your existing
education programs? Contact the Education Coordinator at MUN
Botanical Garden for more information, including a draft of our
Compost Curriculum Unit. This unit was developed during the 2003
Junior Naturalist Camp Program for primary and elementary students
and is available at no cost to interested parents, teachers and
youth group leaders.
Bookings are also accepted in spring and fall from schools, youth
groups, families and community organizations to visit the Garden
and receive one of many garden and nature programs available,
including composting. Members of the public are also invited to
visit the Garden, view exhibits on composting in our display room,
visit the Compost Demonstration Garden and of course stroll through
the flower gardens, visit Oxen Pond and perhaps hike one of our
The following information leaflets are available free of charge
from the Garden:
Information Sheet #1 - The Benefits of Composting
Information Sheet #2 - Let's Compost! What To Compost
Information Sheet #3 - Compost Bins
Information Sheet #4 - Building Your Compost Pile
Information Sheet #5 - Humus: Garden Gold - The Finished
Information Sheet #6 - Winter Composting
Information Sheet #7 - Vermicomposting
To receive the leaflets, or for more information, please
The Education Coordinator
MUN Botanical Garden
Memorial University of Newfoundland
St. John's, Newfoundland, A1C 5S7