Composting with Worms

If you don't have a backyard, or simply don't want to maintain a backyard compost bin, consider worm composting with red wigglers.  It is a simple concept, instead of the small microbes that feast on your organic waste in a backyard bin, you can have worms eat your organic waste.  The resulting compost, called "worm castings", will provide your garden with valuable nutrients.  Composting with red wigglers, also called "vermicomposting", requires less labor than backyard bins, produces no offensive odors, and gives you great fertilizer!

A simple online search can get you information on companies that sell worm bins and worms. You might also consider constructing your own worm bin out of two nested opaque storage bins that can be purchased at many retail locations.

There are two simple requirements: a bin and worms.


Your bin doesn't need to be very big, just 8 to 16 inches deep, 21-24 inches long and 14-18 inches wide is enough, since worms are surface feeders. You can build your own bin by using nesting storage container, or other similar bins. Two bins are needed; as the outside bin will catch the worm tea (food has a lot of water and will generate a lot of liquid as the worms break down the food). Drill ¼-inch holes in the bottom of the bin that nest inside the outer bin. This allows the worm tea to drip into the bottom bin where it can be harvested periodically by using a funnel to drain the worm tea into a plastic bottle with a lid. Worm tea is high in nitrogen, so it must be diluted before use: 20 parts of water to 1 part of worm tea. You can then use it to water indoor or outdoor plants.

Red wiggler worms need air, so you should also drill ¼-inch holes in the sides of the nesting bin near the top. Also, worms don't like the light, so your bin will need a lid. For better air flow, ¼-inch holes should be drilled in to the top as well.

The rule of thumb for bin size is one square foot of surface area per pound of food waste per week. Because worms like moderate temperatures, place your bin in a location that maintains a temperature between 55 - 70 degrees F.  Kitchen countertops or cupboards, closets, basements, or laundry rooms all are great places to keep your bin. Garages in warmer climates or heated garages can also work.

Once you have your bin set up, you'll need bedding material.  Black and white newspaper is the most readily available and easy-to-use bedding material. Tear it into strips about one inch wide and moisten so it is as damp as a wrung-out sponge.

A handful or two of soil, ground limestone or well-crushed eggshells every few months are good for providing grit and calcium. Fill your bin with moistened bedding, toss in a few handfuls of soil, and you are ready to add the worms and food. Over time, the bedding and food are eaten by the worms and turned into dark worm compost. You should be adding new bedding at least twice a year.

You can also use leaves for bedding. Red wiggler worms actually eat leaf mold when in their natural environment. Saving a small quantity of leaves in a plastic bag for that time when leaves are not available is an option.


"Red worms" or "red wigglers" are the worms of choice for worm composting. These worms have a big appetite, reproduce quickly and thrive in confinement. They can eat more than their own weight in food every day! The rule of thumb is 1 pound of red wigglers to ½ pound of food. However, you can order one pound and gradually increase the amount of food placed in your bin from ½ pound to the amount you generate on a weekly basis. The worms will reproduce to accommodate the amount of food you generate, but you need to increase the food slowly.

Worms like to eat many of the same things we eat. Some of their favorites include:

  • Stale bread
  • Apple cores
  • Orange peels
  • Mellon rinds
  • Lettuce trimmings
  • Coffee grounds
  • Leftovers not cooked in oil or sauces (steamed)
  • Vegetable scraps

Do NOT feed them:

  • meats, bones
  • onions
  • dairy
  • oil, fats, grease or
  • pet feces.

The worms will not eat those materials and they could make your bin stink.

Begin feeding your worms only a little at a time. As they multiply, you can add larger quantities of food waste. Bury the waste into the bedding regularly, rotating around the bin as you go. When you return to the first spot, most of the food you buried there should have been eaten. If not, don't worry. Just feed the worms less for a while.

Using Your Worm Compost

Worm compost has a higher amount of nitrogen than most other composts because worms are excellent at digesting food wastes and breaking them down into simple plant nutrients. So, use it sparingly for best results.

You can top dress indoor and outdoor plants with ¼ inch of worm castings. You can also mix the worm casting in to potting soil to give your potting soil more nutrients and water-holding capacity.

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