Worm Composting on the Rise at Home
Copyright by Jim Jensen, YELM Earthworm &
Castings Farm, 1998, firstname.lastname@example.org. Permission
granted to copy or post with complete attribution
in whole, without addition, deletion, or substitution.
A worm bin should have about one square foot of surface
area for each pound of food wastes added per week. For
example, a two-foot by four-foot box is large enough
for eight pounds of kitchen scraps a weekthe amount
produced by two or three adults. Generation of food
scraps varies widely between households, so you may
want to weigh your scraps for a week or two before deciding
what size or how many bins you want to build.
Fill the worm bin with moist "bedding,"
which provides the worms with balance in their diet
and a damp place to live. Composting food scraps without
bedding can produce bad odors and a slimy mess. Common
bedding materials include fall leaves, shredded newspaper
or corrugated cardboard, old straw, coarse sawdust,
and aged dairy or horse manure. Rabbit manure also
works well. Moisten dry bedding materials by immersing
them in water for several minutes before adding them
to the worm bin. When the bedding is thoroughly wet,
remove it from the water and wring out or drain excess
water. Moist bedding should feel damp like a wrung
Fill the bin to the top with loose bedding. This
gives the worms maximum room to grow their population.
Pull apart any compacted paper strips before adding
them to the bin. If brown leaves or sawdust are used
they may need to soak longer to become saturated.
Feed worms by burying vegetative food scraps in holes
dug into the bedding. Bury scraps in a different spot
each time to provide the worms with a balanced diet.
Always cover food wastes with a few inches of bedding
or worm compost (called castings) to discourage flies
and odors. For best results, think of worms as strict
vegetarians. Give them scraps of fruits and vegetables,
grains, old bread, coffee grounds, used tea bags,
and egg shells. But leave out oily foods, meat, seafood,
or dairy products.
Every 3 to 6 months push the old bedding and decomposing
scraps to one side of the bin, rebed the empty side,
and start burying food wastes in the fresh bedding.
Allow the older scraps to finish composting for another
month or so before harvesting.
Harvesting Worm Castings or Worms
One of the real benefits of worm composting is producing
worm excreta (known as castings) for use in your garden.
After a few months, worm castings from a worm bin
will look dark and rich, quite black. To harvest castings
for garden use, simply move nearly finished compost
to one side of the bin and fill the empty side with
fresh bedding (composting reduces the volume of the
wastes by over one half). For the next six weeks bury
food wastes only in the newly bedded side of the bin.
The worms will migrate over to the fresh food in the
newly bedded side as the food on the other side finishes
decomposing. When the old bedding and food scraps
are completely composted, the castings can be harvested
and replaced with fresh bedding. It takes from three
to six months for fresh bedding to decompose. Thus
a worm bin can complete two to four cycles each year.
Harvesting worms for fishing is easy. Just open the
bin and pick a handfull out of the bedding. To harvest
more worms, take a few shovelfulls of castings out
of the bin and make small piles on a piece of plastic
out in the sun or under a bright light. Let the piles
sit for ten minutes, then pull away the surface layer
of castings until you see worms. Repeat the procedure
until the worms are concentrated at the bottom of
the piles and are easy to harvest.
Worm composting bins are relatively trouble free.
The most common problem with worm bins is fruit flies
in summer. Fruit flies can be kept to a minimum by
always covering fresh food wastes with a few inches
of bedding or castings, and by covering the bedding
with a sheet of plastic or newspapers tucked in around
the edges. If the worm bin smells bad, it probably
has too much food waste in it, is too wet, or there
is cheese or other animal products present. To eliminate
bad odors remove excess or inappropriate wastes and
add fresh bedding.
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