Redworms in vermicompost
act in a similar fashion, breaking down food wastes
and other organic residues into nutrient-rich compost.
Nutrients in vermicompost are often much higher than
traditional garden compost (see table 1).
Table 1. Chemical characteristics of garden compost
and vermicompost, 1994.
1Albuquerque sample 2Tijeras sample
|Total Kjeldahl nitrogen(%)***
|Nitrate nitrogen (ppm)****
|| < .01
| Boron (ppm)
| Aluminum (ppm)
||Units- ppm=parts per million mmhos/cm=millimhos
||EC = electrical conductivity is a measure (millimhos
per centimeter) of the relative salinity of soil
or the amount of soluble salts it contains.
||Kjeldahl nitrogen = is a measure of the total
percentage of nitrogen in the sample including
that in the organic matter.
||Nitrate nitrogen = that nitrogen in the sample
that is immediately available for plant uptake
by the roots.
Finished vermicompost should have a rich, earthly
smell if properly processed by worms. Vermicompost
can be used in potting soil mixes for house plants
and as a top dressing for lawns. Screened vermicompost
combined with potting soil mixes make an excellent
medium for starting young seedlings. Vermicompost
also makes an excellent mulch and soil conditioner
for the home garden.
How to Construct a Worm Bin
Bins can be made of wood or plastic, or from recycled
containers like old bathtubs, barrels, or trunks.
They also can be located inside or outside, depending
on your preferences and circumstances.
As red wigglers tend to be surface feeders, bins
should be no more than 8 to 12 inches deep. Bedding
and food wastes tend to pack down in deeper bins,
forcing air out. Resulting anaerobic conditions can
cause foul odors and death of the worms.
The length and width of the bin
will depend on whether it is to be stationary or portable.
It also depends on the amount of food waste your family
produces each week. A good rule of thumb is to provide
one square foot of surface area per pound of waste
in your bin.
Wooden bins have the advantage that they're more
absorbent and provide better insulation. Do not use
redwood or other highly aromatic woods that may kill
the worms. Plastic tends to keep the compost too moist.
Plastic, however, tends to be less messy and easier
to maintain. Be sure containers are well cleaned and
have never stored pesticides or other chemicals. Drilling
air/drainage holes (1/4- to 1/2-inch diameter) in
the bottom and sides of the bin will ensure good water
drainage and air circulation. Place the bin on bricks
or wooden blocks in a tray to catch excess water that
drains from the bin. The resulting compost tea can
be used as a liquid fertilizer around the home landscape.