The scientific name of the species used in vermicomposting is
_Eisenia foetida._ They may be purchased by mail from breeders, from
bait stores, and these days, even from mail-order garden supply
companies. Redworms may also be collected from compost and manure
piles after they have heated and are cooling.
Nightcrawlers and common garden worms play a very important part in
the creation and maintenance of soil fertility. But these species
are soil dwellers that require cool conditions. They cannot survive
in a shallow worm box at room temperatures.
Redworms are capable of very rapid reproduction at room temperatures
in a worm box. They lay eggs encased in a lemon-shaped cocoon about
the size of a grain of rice from which baby worms will hatch. The
cocoons start out pearly white but as the baby worms develop over a
three week period, the eggs change color to yellow, then light
brown, and finally are reddish when the babies are ready to hatch.
Normally, two or three young worms emerge from a cocoon.
Hatchlings are whitish and semi-transparent and about one-half inch
long. It would take about 150,000 hatchlings to weigh one pound. A
redworm hatchling will grow at an explosive rate and reach sexual
maturity in four to six weeks. Once it begins breeding a redworm
makes two to three cocoons a week for six months to a year; or, one
breeding worm can make about 100 babies in six months. And the
babies are breeding about three months after the first eggs are
laid.
Though this reproductive rate is not the equal of yeast (capable of
doubling every twenty minutes), still a several-hundred-fold
increase every six months is amazingly fast. When vermicomposting,
the worm population increase is limited by available food and space
and by the worms' own waste products or casts. Worm casts are
slightly toxic to worms. When a new box starts out with fresh
bedding it contains no casts. As time goes on, the bedding is
gradually broken down by cellulose-eating microorganisms whose decay
products are consumed by the worms and the box gradually fills with
casts.
As the proportion of casts increases, reproduction slows, and mature
worms begin to die. However, you will almost never see a dead worm
in a worm box because their high-protein bodies are rapidly
decomposed. You will quickly recognize worm casts. Once the bedding
has been consumed and the box contains only worms, worm casts, and
fresh garbage it is necessary to empty the casts, replace the
bedding, and start the cycle over. How to do this will be explained
in a moment. But first, how many worms will you need to begin
vermicomposting?
You could start with a few dozen redworms, patiently begin by
feeding them tiny quantities of garbage and in six months to a year
have a box full. However, you'll almost certainly want to begin with
a system that can consume all or most of your kitchen garbage right
away. So for starters you'll need to obtain two pounds of worms for
each pound of garbage you'll put into the box each day. Suppose in
an average week your kitchen compost bucket takes in seven pounds of
waste or about one gallon. That averages one pound per day. You'll
need about two pounds of worms.
You'll also need a box that holds six or seven cubic feet, or about
2 x 3 feet by 12 inches deep. Each pound of worms needs three or
four cubic feet of bedding. A better way to estimate box size is to
figure that one cubic foot of worm bin can digest about one pound of
kitchen waste a week without going anaerobic and smelling bad.
Redworms are small and consequently worm growers sell them by the
pound. There are about 1,000 mature breeders to the pound of young
redworms. Bait dealers prefer to sell only the largest sizes or
their customers complain. "Red wigglers" from a bait store may only
count 600 to the pound. Worm raisers will sell "pit run" that costs
much less. This is a mix of worms of all sizes and ages. Often the
largest sizes will have already been separated out for sale as fish
bait. That's perfectly okay. Since hatchlings run 150,000 to the
pound and mature worms count about 600-700, the population of a
pound of pit run can vary greatly. A reasonable pit run estimate is
2,000 to the pound.
Actually it doesn't matter what the number is, it is their weight
that determines how much they'll eat. Redworms eat slightly more
than their weight in food every day. If that is so, why did I
recommend first starting vermicomposting with two pounds of worms
for every pound of garbage? Because the worms you'll buy will not be
used to living in the kind of bedding you'll give them nor adjusted
to the mix of garbage you'll feed them. Initially there may be some
losses. After a few weeks the surviving worms will have adjusted.
Most people have little tolerance for outright failure. But if they
have a record of successes behind them, minor glitches won't stop
them. So it is vital to start with enough worms. The _only time
vermicomposting becomes odoriferous is when the worms are fed too
much._ If they quickly eat all the food that they are given the
system runs remarkably smoothly and makes no offense. Please keep
that in mind since there may well be some short-lived problems until
you learn to gauge their intake.