|Bin for for composting - Vermicompost Bins
|Vermicomposting bins vary drastically depending on the system an individual composter wishes to create.
|Small scale systems offer a wide variety of bins. Often, small-scale
composters build their own bins. Companies also offer commercial models
for sale. Commonly, bins are built out of old plastic containers, wood,
Styrofoam containers, or metal containers.
Some materials are less desirable than others in bin construction.
Styrofoam is believed to release toxins into the earthworms'
environment. Metal containers often conduct heat too readily, are prone
to rusting, and may release heavy metals into compost.
The design of a small bin usually depends on where an individual
wishes to store the bin and how they wish to feed the worms. All bins
in general have holes for airflow in the sides and some form of
drainage, either holes in the bottom to drain into a collection tray or
an actual spout that can be opened or closed to allow drainage. Plastic
bins generally require more drainage than wooden ones because they are
non absorbent. Regardless of the material used to build the bin, most
small bins can be grouped into three categories:
|Non-Continuous - ? A non-continuous bin is an undivided
container. A layer of bedding materials is placed in the bin, lining
the bottom. Worms are added and organic matter for composting is added
in a layer above the bedding. Another layer is added on top of the
organic matter and the worms will start to compost the organic matter
and bedding. This type of bin is often used because they are small in
size and easy to build. They are relatively difficult to harvest
because all the materials and worms must be emptied out when harvesting.
|Continuous Vertical Flow - ? Continuous flow bins are a series
of trays stacked vertically. The bottom-most tray is filled first, in a
similar fashion to any other bin, but is not harvested when it is full.
Instead, a thick layer of bedding is added on top and the tray above is
used for adding organic material. The idea is that the worms will
finish composting the bottom tray and then migrate to the one above.
When a sufficient number of worms have migrated the bottom tray can be
collected and should be relatively free of worms. These bins provide an
easier method of harvesting.
|Continuous Horizontal Flow - ? A continuous horizontal flow
bin is another bin that relies on the earthworm's habit of migrating
towards a food source in order to ease the process of harvesting. The
bin is usually constructed to be similar to a non-continuous bin but
twice as long (horizontally). The bin is divided in half, usually by a
large gauge screen of chicken wire.
Only one side is used initially. When that half becomes full, the other
half is filled with bedding and organic matter. In time, the worms will
migrate to the side with the food and the compost can be collected.
These bins are larger than a non-continuous system but are still small
enough to be used indoors, with the added bonus of being easier to
|Large scale - Most large scale vermicomposting or vermiculture systems do not
incorporate an actual physical bin at all, because it is simply too
impractical. A large system will usually use a windrow.
The windrow simply consists of bedding materials for the earthworms to
live in (see bedding below) and acts as a large worm bin; organic
material is added to the windrow and the worms perform the composting.
Although the windrow has no physical barriers to prevent worms from
escaping, in theory they should not due to an abundance of organic
matter for them to feed on. Often windrows are used on a concrete
surface to prevent predators from killing off worm populations.
|Starting Off - When beginning a vermicomposting bin, add as many composting worms
as available. They should be added to moist bedding. Quantities of
kitchen waste appropriate for the worm population can be added to the
bin daily or weekly. At first, feed the worms approximately 1/2 their
body weight in kitchen scraps a day, maximum. That is, if you have 1 kg
of worms, you should feed them about 1/2 kg of kitchen scraps a day.
After they have established themselves, you can feed them up to their
entire body weight.
|Bedding - Bedding in a worm bin is the living medium for the worms but is also
used as a food source. It is material that is high in carbon and is
made to mimic dried leaves on the forest floor, which is the worms'
natural habitat. The bedding needs to be moist (often related to the
consistency of a wrung-out sponge) and loose to enable the earthworms
to breathe and to facilitate aerobic decomposition. A wide variety of bedding materials can be used including newspaper, sawdust, hay, cardboard, peat moss, aged manure
(meaning the manure has to be pre-composted before use), and dried
leaves. Most vermicomposters avoid using any glossy papers from
newspapers and magazines, junk mail
and shredded paper from offices, because they may contain toxins which
will severely affect the system. Also some cardboard cannot be used if
it contains wax or plastic, such as cereal
boxes, and other boxes designed to hold food items. Newspapers and
phone books printed on regular, non-glossy pages are heavily regulated
by the FDA and use non-toxic soy and Canola based inks (see Soy ink). Some beddings are easier to use and add food scraps to than others.