Building a Worm Composter
Adapted from Composting in your Apartment or House Workshop
October 19, 2010
2 or 3 stackable, large, shallow plastic bins with lids, recycled/reused if possible; dark colored is
Duct tape or something else to darken the bin if it is see-through
A small amount of dirt
Red wiggler worms – You can get some from a friend who also worm composts or buy
approximately one pound. I bought them from Compost Critter:
garden&ie=UTF8&qid=1293412849&sr=1-4 Other species also work, but these are the most
common. However, normal earthworms in your garden will not work.
Rods of some kind (optional)
The only things needed for worm composting besides the food are a worm bin, newspaper, and worms
themselves. The newspaper acts as bedding, which they eat along with the food. To keep your worms
healthy, it's best to add food continuously for about three months or so and then change their food and
bedding. At that point, they will have eaten most of the food in there and be surrounded by compost
(otherwise known as their own waste). As you would like to get to that compost and they don't have
anything else to eat, it's important to remove them from the bin and add completely new bedding and
food. There are two methods to doing this. You can manually sort through the worms, picking them
out and placing them in their new home or you can construct a bin where they climb through holes in
the top to reach the new food. This method allows the worms to climb, but if you don't mind manually
transferring them, leave out the third plastic bin.
1) Drill 5-10 large (¼ inch) holes in two of the three plastic bins. The number of holes will depend
on the floor area of the bin. They should be large enough to allow water drainage and/or worms
to crawl through them.
2) If the bins are translucent, cover the lid of one of the bins with duct tape or some other dark
material. Worms like being in the dark.
3) Drill holes in the lid you covered with dark material. These don't need to be very large, as they
are for air.
4) Stack one of the bins with holes in them on top of the bin without holes in it. The bin on the top
will be where the worms will live and the bin on the bottom will catch any water that drains.
5) If the bins are stacked tightly, you may need to separate them a bit to maximize air flow.
Without air flow, the worms will die. We stuck thin wooden rods in-between the bins to do this
and it seems to be working well.
6) Add a very small amount of dirt and then a layer of crumpled newspaper.
7) Add the worms. Wait a few days for them to get accustomed to their new home before adding
food. It's likely they will try to escape, and you may end up with a few dead worms around the
box. You can discourage this by leaving the light on wherever the worm box is.
8) Put the top back on the top box.
9) Add organic food scraps. The worms seem to like soft food the best, and avoid harder objects
like broccoli stems. Although they can eat them, they don't seem to eat teabags either. Don't
add too much food at one time or it will begin to go back and attract flies. (You may have to
learn what is too much by trial and error!) Add a layer of newspaper over the food to prevent
fruit flies and provide them with more bedding.
10) When the time comes to change the worms' bedding, stack the second bin with holes on top of
the first and place the lid on the second bin. Prepare the second bin the way you did the first
one, but without the dirt. Wait for the worms to come up!
Worms Eat my Garbage, Mary Appelhof: http://www.amazon.com/Worms-Eat-My-Garbage-