By Lee Oliphant,
Ed.D., Master Gardener
Traditional composting is not for everyone. Some folks just don’t have the space for
composting bins but would love to have some of the “black gold” plant food that
composting provides. If you want to try
composting on a smaller, more concentrated level, worm composting (or
vermicomposting) might be the answer for providing food for your plants while
recycling kitchen scraps, lawn clippings, and newspaper clippings. The resultant castings provided by worm
composting is a potent additive to soil or can be mixed with water as a “tea”
for potted plants.
Worm composting requires a shady, cool place for your worms to live. You will need only a few things to begin worm
composting: a worm bin, newspaper bedding, kitchen scraps and, of course, your
little “Red Wigglers” (Eisenia foetida).
Your Worm Bin
Commercial worm bins are available but to begin your worm composting you might
want to purchase a simple 5 to 10 gallon plastic tub with a lid that snaps
shut. Worms like darkness, so an opaque
bin is best. Drill 1/4 inch holes around
the bin about 4 inches down from the top and 2 to 4 inches apart.
Worms thrive in temperatures between 50 and 75 degrees. Options for bin locations are the garage,
basement, a shady deck or area in your garden, or in a garden shed.
Worm Bedding
In their natural habitat, “Red Wigglers” live in piles of fallen leaves above
the soil surface. The best bedding in
your bin is shredded rough paper such as uncolored newsprint or cardboard. Prepare your worm bedding by wetting the
paper and wringing it or drain it until is like a wrung-out sponge. Separate the damp strips. Add a handful of fine sand or sawdust for
grit to help your worm digest the bin contents.
Worm Food
A pound of red worms need about a pound of scraps each week. They eat just about any part of fruits and
vegetables, coffee grounds and filters, tea bags and watermelon rinds. To begin, layer about a pound of scraps over
the bedding. Avoid putting meat, oils,
cat or dog feces, or dairy products in your bin. While worms can survive longer without food,
they enjoy a weekly feeding.
The Worm Crew
”Red Wigglers” (not to be confused with earthworms) can be purchased at garden
centers, bait shops or from suppliers on the Internet. You will need less than a half-pound of worms
to begin your worm composting. Worms
need to be separated from their casting about twice a year. One method for separation is to push the
decomposed material to one side of the bin and remake the worms’ bed with paper
and kitchen scraps.
Another method for those of us who can’t wait for the wigglers to meander to
“greener” pastures so that castings can be harvested is to expose the open bin
to bright light or sunlight. The worms
will dive for darker quarters. After a
few minutes, remove the top inch (sans worms) and repeat.
Your Payoff
Worm compost is ready to use when all vegetation has been digested. It is very concentrated. You can sprinkle and dig it into freshly
cultivated soil or mix one part worm compost to four parts potting mix. Compost “tea” is made by putting compost in a
cloth bag and soaking it in water for a few days. Use the tea to water your plants.
There are many informational resources for worm composting available. “Worms
Eat My Garbage” by Mary Appelhoff is a book that provides extensive
coverage on the subject. Her Web site is
wormwoman.com.