Northern Alberta Institute of Technology

How to compost indoors with worms

Reduce waste and feed your plants

worm composting NAIT polytechnic EdmontonVermicomposting is the process of using worms to break down food waste – and it can be done indoors, making it a great option for those living in apartments or condos. Not only will composting with worms reduce the amount of waste you send to the landfill, but the resulting fertilizer will benefit your plants.

Start vermicomposting with these steps from NAIT Biological Sciences Technology instructor Dave Critchley (class of '98, Forest Technology '99) and program alumna Joanne Pinches (Bio. Sci. Tech. – Renewable Resources '09). 

What you’ll need

  • Container - A plastic container with a lid is ideal. Drill holes along the sides, near the top to allow for air flow and to help regulate moisture. Allow 900 square centimetres for every 450 grams of waste you expect to produce in one week. Store the container in a dark, warm area (at least 16 C) in a location where you’ll remember to use it, such as under the kitchen sink, in the pantry or in a heated garage.
     
  • Bedding material - Fill your bin with a mix of bedding materials. Options include soil, shredded newspaper, straw, dry leaves and sawdust (avoid sawdust from spruce and pine trees, as well as wood products with the laminate melamine). Wet the bedding materials, using water or fruit or vegetable juices.
     
  • Red wiggler worms (Eisenia fetida) - In one to seven days, 450 grams of worms can eat 225 grams of food waste and bedding material. Start with 225 grams of worms. Under ideal conditions, a small number of worms can reproduce dramatically in a short period of time. In the Edmonton area, you can buy red wigglers from Earth’s General Store and Dirt Willy Farms.
     
  • Kitchen waste - What you can compost: fruits, vegetables, coffee and tea grounds, egg shells, dairy, meat, oils. Consider putting food scraps through a food processor to break down the pieces and speed up the vermicomposting process. Freeze the waste first if possible, as this will kill most microbes founds in the peels, leaves and other scraps. Bury the food under a minimum of two centimetres of compost/soil to help keep undesirable insects out, such as fruit flies.

Subscribe to receive more great stories every month

Find out more news about NAIT, stories about our alumni and their impact on their communities, and useful how-to content featuring our experts.