Indoor Composting: You Can Still Compost in Winter

Has your trip into the back yard turned into a human endurance contest? Are you tired of cold water dripping down your neck or having to dress for skiing just to take your compost out? You don't have to brave the elements to compost; you can compost in warmth and comfort indoors!

Indoor composting is very similar to outdoor composting, except that you have to pay more attention to preparing your composter for its working residents. In the back yard, you can basically pile up a bunch of garden debris in spring and summer and the "composters" will find it and go to work. You don't want all those black beetles, centipedes, sow bugs, and earwigs in your house or apartment, though. Indoor composting is dependent on red worms, which, properly fed, will work overtime to transform your kitchen waste into rich black loam.

Red worms love to eat organic matter. In fact, a single red worm can eat up to its own body weight in food scraps every day! You can't just go out into your yard and dig some up and bring them inside, though. Red worms, also known as red wigglers, brandling or manure worms, are normally found in habitats such as aged manure piles, and often sold as fish bait. They like it warm, being happiest at room temperature.

So for successful indoor composting, you'll need red worms and a suitable home for them.

First, you'll need a container or worm bin. A plastic utility container approximately 24 inches by 16 inches by 10 inches is convenient for storing under the sink or in a cupboard. You can get or build a simple wooden box if you prefer, but plastic or wood, the container needs to be 8 to 12 inches deep, with holes drilled in the top and sides for air circulation and holes drilled in the bottom for drainage. You'll want to put a tray under the container to collect any seepage, and may also want to put the container on bricks to improve the air circulation.

Second, put about a foot a damp bedding into the container to serve as a living space for the red worms. You can use sawdust, shredded cardboard, shredded leaves, dried grass clippings, loam, black topsoil, or newspaper (the kind with non-toxic ink) as bedding material. Whatever material you choose, it has to be about as moist as a wrung-out sponge. You don't want your red worms to shrivel up or drown!

Third, add your red worms. In fishing season, you should be able to find red worms anywhere that sells bait. You can also buy them from companies that specialize in vermi-composting supplies, or from garden centres. Plan on using one-half-pound of red wigglers for each cubic foot of worm bin; (one-half-pound of red worms is about 500 worms, depending on their size).

Fourth, collect your kitchen scraps and feed the worms. I like to use a small pail which I fill with "worm treats" such as tea bags, coffee grounds and filters, vegetable and fruit scraps, bread, rice, and pasta. (Don't feed them meat scraps, bones, dairy products, garlic or potato peelings.) When the pail is full, I pull aside the bedding in the worm bin, bury the food waste deeply, and cover it with bedding again. Voila! The worms do the rest!

To keep the red worms especially happy (and productive), I like to add a handful or two of garden soil each time I feed them, to help their digestion. I also sprinkle crushed egg shell over the top of the pile every other time I feed them, to prevent the bedding from getting too acidic.

Four to six months later, the red worms will have turned their bedding and food into rich, black soil and it will be time to harvest the finished compost. The easiest way to do this is to move the compost to one side of the bin, and put fresh bedding on the other side. If you add food only on the side with the fresh bedding for a few weeks, all the worms will move to that side, and you can then remove the compost from the "unpopulated" side of the bin. Add some more fresh bedding, and continue feeding as usual until it's time to harvest again.

So instead of putting your composting activities on hold for the winter, or freezing yourself while you trudge out into the back yard with yet another pail of kitchen scraps, why not put some red worms to work for you and compost indoors? Indoor composting is clean, odorless if you do it right, and a great way to cut down on the amount of trash you set out by the curb every week.