Getting to know who your friends are
How to make a backyard worm farm
Anna May Kinney
Since Charles Darwin pointed it out to us, we have known
that compost or manure worms are the best way to improve the structure of soil. Since his
day, many organic gardeners and researches have come to the same conclusion, that these
fascinating little creatures do more for the gardener than any amount of artificial
fertilizer could ever do.
If you are wondering how you could employ these little garbage eaters to work for you,
here is a simple method called the back yard worm farm.
For those living in areas that do not experience a hard freeze during the winter months,
this worm farm can stay outside year round, but here in the north, you will have to put it
in the basement during the coldest part of the year, usually from December first till
March first, or your worms will freeze.
To start with you need a large plastic bin with lid. Make a double row of small drainage
holes around the bottom of the bin. Next, put about 2 to 3 inches of sand/gravel for
drainage and on top of this lay slats of wood with gaps between them.
Once this is all in place you can add about 4 to 6 inches of bedding material and your
worms. From then on you feed your worms with vegetable waste from the kitchen. The food
layer should be no more than 5 inches thick each time you add it, otherwise it will begin
to rot before the worms can eat it and then become a stagnant smelly mess and your worms
A suitable bedding mix would be peat-moss mixed with horse muck, this allows a safe place
for the worms to live while they settle into their new home and somewhere for them to go
if the vegetable waste begins to heat up and compost.
Next, we add some worms. The types of worms to use in a worm farm are the Brandling or
compost worms. Common earth worms are no good for the job! Brandlings can be found in most
compost bins or bought from specialist suppliers or fishing tackle shops; these are the
worms used as bait by fishermen. For an average bin worm farm you will need about 200 to
300 worms. Worms work at their best in a temperature range of 10 - 20 C (48 to 68F).
Worms will eat just about any vegetable waste from the kitchen such as outer leaves of
cabbage, lettuce etc so long as they are not cooked! DO NOT put in cooked meats, perennial
weeds from the garden, too much citrus peel or grass cuttings, they are all bad in one way
Cooked vegetables, meat and cheese would likely attract rats or cats, and most of these
things can cause decomposition that would heat up and eventually kill your worms. The
secret of feeding worm in the bin is little and often. If you produce too much kitchen
waste for the worms to handle then partially compost it in the usual way and once it is
COOL you can then add it to the bin.
Most people experience very few problems with this type of worm farm. But always remember
to keep the bin moist but never soaking wet. Put a lid on to keep the rain out, the worms
will not escape if all is well. If the bin begins to smell a little rotten sprinkle a some
calcified seaweed on the surface and gently stir it in, this will neutralize any acid.
Once the bin is full of worm casts you can empty it out and use the casts on the garden,
the worms will be in the top 6 inches of the bin so it is a simple job of scraping the top
layer off and using it to start the bin over again. The best time to empty the bin is when
the latest layer of food has just about been eaten up; this ensures that the worms are
where you want them i.e. in the top 6 inches.
Now that you have a good supply of worm casts, what do you use them for?
Always remember to keep the lid on your worm farm so it is not exposed to rain, keeping
the worm casts dry is important, and once you have harvested them from your back yard farm
keep them in a dry place, so that they will be easy to mix and spread by hand.
If they are already clumpy, spread them out where they can dry, then bag.
This product is loaded with nutrients and it is ideal to for sprinkling around growing
plants in the vegetable garden, much like you would with a purchased bag of granular
fertilizer. This compost is so highly concentrated that only a couple of handfuls to the
square yard are necessary. It is so highly concentrated that it should not be used as
potting soil by it's self.
Worm casts compost becomes a great lawn dressing by mixing together 2 parts of sand, and 1
part of neat worm casts. To every 5 gallons of this mixture add a handful of calcified
To make a multi purpose potting soil, equal if not better than anything you will find in
the store, mix worm casts 50-50 by volume with peat moss, or cocoa fibre. To every five
gallons of this mixture add about one good-sized handful of calcified seaweed. Calcified
seaweed contains over 20 minerals and trace elements that are beneficial to plants.
The product you are left with can be used as potting soil for most any kind of outside or
house plant, for starting seeds in the spring time, raising cutting, and in most any kind
of container, including hanging baskets.
Imagine taking your scraps, and getting back a product that has only cost you a little
time. You'll be saving money and doing something to help the environment at the same time.