Composting food scraps indoors

compost indoors with worms

Use red wiggler worms to recycle food waste indoors with minimal space and no bad odor.

  • Red wiggler worms are very effective at composting kitchen food scraps. They reproduce quickly and are easy to maintain.
  • They are perfect for homes, townhomes and apartment dwellers because they take up little space.
  • Use the nutrient-rich worm compost ("castings") on your plants and in your garden.

Set up your bin

A bin specially designed for vermiculture can be purchased online, or you can make your own.

Make your own bin: Purchase two opaque nesting storage bins, about 8 inches deep by 16 inches wide by 2 feet long. Drill holes in the bottom of the inside bin, using a 1/4 to 3/8 inch drill bit. This allows liquids (worm juice) generated in the composting process to drip into the bottom bin. Drill air holes in the lid of the top container or along the sides of the inside container about one inch above the bottom bin.

Bedding: Common materials are peat moss, shredded paper or newspaper, and leaves. Don’t use paper with colored inks—it may contain toxic metals. A mix of bedding materials will provide a richer source of nutrition for the worms. A handful of dirt or sand may be added to the bedding to help the worm’s digestion.

Add food waste and worms

worms redwigglersCollect food scraps three or four days before you are ready to begin worm composting. This gives the food time to start to decompose so the worms will be able to eat it quicker. Store scraps in a sealed container to avoid attracting flies or pests. Refrigerate if needed. Add food waste and worms: Dig a hole in the bedding with a hand trowel or rake, place the food then the worms in the hole and cover with bedding.

Acceptable materials

  • uncooked fruit, grain, or vegetables
  • coffee grounds and tea bags (not too much)

Materials to avoid

  • meat, fish and other animal products
  • dairy products
  • egg shells
  • greasy or fried foods
  • pet waste

How many worms do you need?

For every half-pound of food you collect, you need one pound of worms. To save money you can purchase one pound of red worms (Eisenia fetida), begin feeding one-half pound of food per week and gradually increase the amount of food you put into the bin. The worms will increase in number to match the amount of food put into the bin.

Worms like dark, moist conditions. Dampen the bedding by adding water a little at a time. Check the moisture of the bedding by taking a handful of material in your fist and squeeze; you shouldn’t be able to squeeze out more than a drop or two of water. If bedding becomes too wet, you may experience odor problems. Add dry paper to soak up excess water. Keeping the bedding damp provides good living conditions for the red wigglers and prevent pests.

Where to purchase red worms (Eisenia fetida)

Care and feeding of your worms

Place the bin in an area where the temperature stays between 50 to 75 degrees F. They will not survive winter temperatures, so an unheated garage or outside will not work. The closet, under the kitchen sink, or basement are perfect locations for the bin. Each time you feed the worms create a different hole. The worms will migrate to the food. Worms do not like to be disturbed, so add food scraps to the bin once or twice a week.

Tips for taking care of your worms

  • Only add enough food for the worms to eat.
  • Overfeeding may cause odors or fruit flies.
  • Cutting up the food scraps will speed up the process (not too much).
  • Fluff up the soil to make sure it doesn’t get too compacted—it will maximize air exchange and movement for the red wigglers.

Harvesting the worm compost (castings) and liquid

hands with worms castings in dirt compostWorms work quickly. In two to four months, you should notice a build-up of dark, rich material, or castings. Around six months, you will need to harvest the worm castings. Harvest castings by shifting everything in the bin to one side. Place new bedding on the other side and bury food in the new bedding. Continue to feed the worms only on this side. In about two weeks, the worms will have migrated to the new side. Collect the castings from the other side and add bedding. Continue harvesting one side at a time. A silty liquid will collect in your bottom bin after a while. Use a piece of cheese cloth to strain out the silty materials. Reserve the liquid in a container and mark the container clearly.

Using the worm castings and juice

worm teaUse the castings to top-dress indoor or outdoor plants or as part of a mix for potted plants. Worm castings are a potent source of nutrients for your plants—use them sparingly, about one handful of worm castings to ten handfuls of soil. Top-dress the silty material on indoor and outdoor plants. The remaining liquid, or “worm juice,” is a strong fertilizer that should be diluted 20:1 prior to use. The liquid may be used to water your garden, indoor or outdoor plants, flowers, shrubs or trees. Worm juice may have anti-fungal properties that can prevent fungal diseases, such as black spot, when sprayed on plant foliage.