How to Make Worm Composters


So you've heard that common fishing worms can turn kitchen garbage into one of the best natural composts on the planet, but it may strike you as being a large outdoor operation. Not necessarily so. If your apartment doesn't include a big yard or "back 40," there's no reason your patio plants can't enjoy the same nutrient-rich compost that's loved by gardeners who have lots more room than you do. Just scale the worm composter down to a small contained environment that the critters will eat and miraculously process into black gold. This is not only a cheap, easy and self-renewing source for great organic matter, it's also a fun project to share with your kids on an ongoing basis. They'll think they're getting a whole bunch of new pets. Make sure you obtain red worms, or "red wigglers," which re-purpose garbage faster and more efficiently than other species. They're readily available from bait retailers, in mail-order catalogs and online.

Making Your Worm Composter

Step 1

Drill 20 to 30 drainage holes in the bottom of both bins, spacing them somewhat evenly apart. Make the holes about 1/4 inch in diameter, which is large enough for the worms to crawl through when it's time for them to relocate. Use a 1/16-inch bit to drill a row of holes 1 inch apart all the way around the sides of each bin, about 1 1/2 inches from the top for ventilation. Drill a similar set of holes in each bin all the way around about 3 inches below the top row. Drill 30 to 40 small holes in the red bin's lid, and set the red bin and lid aside for use later.

Step 2

Tear black and white print newspapers into strips about 1 inch wide and drop them into a garbage can or other large container. You'll need to fill the container with strips, so it's a good idea to enlist the kids and their friends for this. Avoid using pages printed with colored inks, which don't agree with wormy gastrointestinal systems.

Step 3

Slowly add quarts of warm water to the paper strips, stirring as you go to moisten them thoroughly. Use enough water to just cover the paper, and allow the mixture to soak overnight. Worms need adequate water content in the bedding to keep their skins moist and supple for burrowing activities.

Step 4

Scoop dampened newspaper by the handful and squeeze out excess water. It should be moist but not soggy or dripping, like a squeezed-out sponge, as you deposit it into the blue bin. Fluff it up or pull it apart with your fingers so that it's firmly, but not tightly, packed. Cover the bottom of the blue bin with 3 to 4 inches of moist newspaper.

Step 5

Add organic bedding materials one thin layer at a time, working them very loosely into the top of the newspaper layer. You can use dried grass clippings, sawdust, pulled weeds, aged manure, shrub trimmings, peat moss, hay and dried crumbled-up leaves. Avoid oak leaves, which are highly acidic--worms don't like acid environments. Any combination of materials is fine--this is worm bedding, not rocket science. Spritz the surface of each layer lightly with water from a plastic spray bottle to maintain an overall moisture consistency of a squeezed-out sponge. Fill the bin to about three-quarters full.

Step 6

Sprinkle a handful of ground limestone over the bedding to provide your worms with calcium. Mix in a handful of vermiculite to keep bedding from compacting. Add a handful of sand or soil, which the worms will consume to aid their digestion.

Step 7

Add 1/2 to 1 lb. of worms to their new home. Gently shake the worms from their container and spread them over the surface of the bedding. They'll immediately begin squirming and burrowing into it to escape the light.

Step 8

Cut a stiff piece of cardboard to roughly fit on top of the bedding, and drill 30 to 40 small aeration holes in it. Set it on top of the bedding and soak it with water. Choose a well-ventilated spot out of your way, such as under the kitchen sink, in the garage or in the laundry room. Turn the blue lid upside down to serve as a basin to catch draining "worm tea," which is great liquid fertilizer. Set a couple of bricks or blocks on top of that, and place the composter on them.

Step 9

Chop collected kitchen scraps and carefully bury them in the bedding under the cardboard every 3 to 5 days. Chopping food will enable the worms to process it more efficiently. Choose a different spot for each subsequent addition. Feed your worms fruits, vegetables, tea bags, coffee grounds with the filters, crumbled eggshells, breads and cereals. Never give worms meat, fat, grease, oil or dairy products, which they won't eat. Those foodstuffs will only serve to attract insect and rodent pests, and they'll stink. Don't feed rotted materials.

Step 10

Repeat Steps 2 to 7 using the red bin when the blue bin is full and you no longer see recognizable bedding or food scraps. Remove the cardboard and set the red bin directly on the surface of the old bedding, and cover it with the red lid. Start burying food scraps in the new red bin to invite the worms to migrate to their newest home. Within a month or so, most of the worms will have crawled up from their old bedding through the holes in the bottom of the red bin as they search for food. In another couple of weeks, all should have relocated, leaving you a bottom bin full of ready-to-use worm poop, or vermicompost.

Worm Composter Care and Troubleshooting

Step 1

Dampen the bedding if it feels a little dry to the touch. Worms will try to escape or will die without adequate moisture.

Step 2

Drill more ventilation holes in the compost bin if it begins to smell bad. Poor air circulation can cause it to stink. If after a few days the odor hasn't cleared up, add a little dry bedding material to absorb any excess moisture from the environment that may simply be too wet. Your worms will drown in excessive water, and survivors will be trying to get out of it.

Step 3

Eliminate feedings if the composter continues to stink. Give the worms a chance to consume food that's already there for about 1 to 2 weeks by withholding additional feeding materials.

Step 4

Check the surface of the bedding for any exposed food if you see fruit flies hanging around. That's what they're after, so make sure to bury all foodstuffs thoroughly.

Step 5

Watch the active blue composter carefully so that you'll know when the bedding supply is used up or nearly depleted. You'll need to get the red bin into place quickly thereafter, because the worms will starve to death or try to escape if there's no food available to them.

Tips and Warnings

  • Don't feed your worms meat, dairy, oil, or greasy products or byproducts. They won't eat those materials, which will only rot, stink and attract unwanted insect and rodent pests.

Things You'll Need

  • Two heavy-duty opaque-plastic 10-gallon bins with lids, one blue and one red
  • Drill
  • Newspapers--black and white print only
  • Garbage can or other large container
  • Organic bedding materials
  • Plastic spray bottle
  • Ground limestone
  • Vermiculite
  • Sand or soil
  • 1/2- to 1-lb. live red worms (red wigglers)
  • Worm food


  • Home Vermiculture
  • Worm Composting
Keywords: worm composter, composter, how to make worm composters

About this Author

Axl J. Amistaadt began as a part-time amateur freelance writer in 1985, turned professional in 2005 and became a full-time writer in 2007. Amistaadt’s major focus is publishing garden-related material for various websites, specializing in home gardening, horticulture, alternative and home remedies, pets, wildlife, handcrafts, cooking and juvenile science experiments.