Indoor Composting

If you don't have much space outdoors or are an apartment dweller, you can still compost small amounts of material! There are a couple of ways to go about doing composting indoors: hot composting and worm composting. Both are explained below. Happy indoor composting!

Hot composting indoors is fairly simple to learn.  First you put some holes in the bottom and around the top of a box.  The box does not have to be huge, but should have at least several cubic feet of space.  Styrofoam shipping coolers work really well. 

You can also use plastic or wooden containers or a specially designed container for indoor composting, provided the wood isn't treated with anything toxic.  It's a good idea to screen off the holes, especially at the bottom to keep material from falling out.  If you are concerned about fruit flies, you can cut up a pair of old pantyhose and use the nylon strips to cover your holes in addition to a mesh screen.  Set the box on four blocks to raise it a couple inches off the ground for ventilation.

Once your box is built, layer the bottom with two to three inches of shredded paper.  Staple-free coarsely shredded paper works fine, and you want to avoid using glossy paper.  You can also use other carbonacious material such as dried leaves, dried grass clippings, sawdust, peat moss, and other materials.

Next, collect enough kitchen scraps to form a layer on top of the paper layer of about the same size.  When you have enough material collected, spread it over the paper, and cover completely with shredded paper.  Try to avoid having the scraps contact the wall directly—have paper between the wall and the scraps.  If you want, you can throw in a handful of dirt with the kitchen scraps but that is not strictly necessary.  You are now ready to add your second layer of kitchen scraps.  Keep adding layers of scraps followed by layers of dry shredded paper until the box is full.  It will accept a surprising amount.  Once the box is full, you will need to give it time to age. Start a new box at this point.

Hot composting indoors can work well, and it's exciting to see a meat thermometer consistently register 110-130 degrees.  It does have some disadvantages, though.  One is that shredded paper doesn't completely cover up all odors.  This may improve by using a different cover material such as sawdust or peat moss, and by keeping the scraps away from the box walls.  The other problem is that molds and little insects proliferate, which can cause allergies and other issues.  For this reason, hot composting may be better suited for a well-ventilated garage than say, your kitchen.

Since your compost pile is indoors, it won't have access to all the beneficial organisms normally present in a healthy outdoor pile.  For this reason you may find you have to turn it more, and you might need to inoculate it with various compost critters along the way.

Indoor Composting With Worms

A form of indoor composting that is gaining in popularity is worm composting, also called vermicomposting.  Worm composting means exactly what it sounds:  using earthworms to break down your unwanted organic matter.  Worms will happily go to work on a combination of kitchen scraps and some sort of carbonaceous bedding material and turn the whole thing into vermicompost, which is a combination of worm castings and organic material in various stages of composting.  You can get more worm castings by leaving your worms to work on the same material for longer.  However the longer the worms have to live in their own poop, the less well they fare.  Every worm composter has to strike the balance that works best for her situation.

Setting up a worm composting system is fairly simple.  You need a box with ventilation holes around the top and through the bottom, and a lid.  You can use almost any kind of wooden or plastic box.  Styrofoam coolers, often used to ship materials on ice,  work very well.  You can screen the holes with a mesh material such as that used for window screens to keep material from falling through the holes on the bottom and to keep your worms from escaping, but you can usually get away without screening.

Once you have built your worm box, you need to fill it with bedding.  Shredded newspaper is easy to obtain and works quite well.  Other possibilities are peat moss, composted manure and coconut coir.  The bedding needs to be moist like a wrung out sponge before adding the worms.  You can fill a spray bottle with water and liberally spray the bedding as you layer it in.  Add a handful of dirt or sand to the bedding to provide the worms with grit.

Next, you add the worms.  If you are using composted manure, be sure to wait about three days from the time you wet the bedding before adding worms because wet manure has a tendency to heat up.  This is not of concern for any of the other beddings.  You can order worms from a supplier who caters to worm composters.  You want the worms to be Eisenia foetida, commonly known as redworms or red wigglers.  You can also purchase them from a bait shop, though that tends to be more expensive.  One pound of worms will process around a half pound of kitchen scraps per day, so you want to order enough to meet your needs. 

Once you have worms you can start to bury kitchen scraps in the bedding.  You can bury your scraps in a different part of the box each time following a systematic plan.  Your worm box should be big enough that you will not have to return to the same burial spot for a couple weeks or so. This will allow the scraps to begin decaying, at which point the worms will start eating them.

Worm composting can be fun and rewarding, especially when you get to start using the worm compost in your garden or potted plants.  The easiest mistake to make is feeding the worms too many scraps. This can lead to the worm bin heating up to uncomfortable temperatures.  So, make sure you order enough worms to process the load of scraps you plan to feed them.