Vermicomposting: Composting with Worms

Worm composting is an efficient method of turning kitchen waste and small amounts of garden waste into nutrient-rich compost and a concentrated liquid fertiliser. However, it isn’t an alternative for conventional composting.

What is a wormery?

A ‘worm bin’ or ‘wormery’ usually contains at least two compartments; a lesser collection sump for the liquid and an upper composting area the location where the kitchen waste gets into and the worms actively work. However, single compartment wormeries can be used.

The worms used for composting are known by various names; brandling, manure, red or tiger worms. Included in these are the species Eisenia foetida, E. andreii and Dendrabaena veneta. Composting worms are in decaying organic and natural matter, whereas earthworms are soil dwellers. They are simply smaller and darker red than the normal earthworm, Lumbricus terrestris, which is unsuitable for using in worm composting.

Worm Composter – Starting a wormery

A wormery is relatively easy to establish though a few points have to be considered.

Conditions required

  • Worms are most active in warm moist conditions, ideally between 18-25ºC (64-77ºF)
  • Their activity noticeably declines below 10ºC (50ºF) and above 30ºC (86ºF)
  • A wormery should be kept in a shed or a sheltered section of the garden where it gets neither too cold in the winter nor too hot in the summer
  • If thinking about keeping wormeries in your kitchen, utility room or on the balcony, consider that whenever neglected they will often produce odours
  • Composting worms prefer a pH of between 6.5-7.0, and well-ventilated conditions to live in
  • They will not tolerate extreme acidity and dislike being waterlogged because this restricts their way to obtain air

Using your wormery:

  1. In the bottom, place an 8cm (3¼in) layer of moist ‘bedding material’ such as old compost or coir if it is provided by the supplier. This creates a humid layer where the worms can burrow and get started to digest their food
  2. Add the composting worms
  3. Cover with no more than 8-10cm (3¼-4in) layer of kitchen waste
  4. Leave for about one week to permit the worms the perfect time to settle into their new environment

Feeding the worms (adding waste):

For best results, add small amounts of waste often to the wormery.

  • Chop the waste into smaller pieces so that it can be eaten faster
  • Place the food on the top of the compost
  • Alternatively, bury the meals within the compost to produce feeding pockets
  • If the waste is not being eaten, feeding should be stopped for a couple of days till the worms learn to work through the top layer of the composting material
  • Avoid adding more waste than the worms can handle

What to compost

Worms enjoy a varied diet eating any decaying organic and natural matter. You may put in;

  • Any raw vegetables, aside from onions, shallots, leeks and garlic that are best found in small amounts or cooked first
  • Any cooked vegetables
  • All fruit, except citrus peel, which needs to be limited or preferably cooked before adding
  • Tea bags, eggshells, coffee grounds and smaller amounts of bread
  • Limited amounts of newspaper, shredded office paper and cardboard, however, not glossy magazines
  • Small amounts of garden waste such as twelve-monthly weeds, leaves and other soft green material