18th - 24th September 2023
Hot Composting Week Homepage

Worm Composting

Put little wrigglers to work!

What is worm composting?

Worm composting is using worms to recycle food scraps and other organic material into compost called worm compost or vermicompost. Worms eat the scraps, which become compost as they pass through the worm's body. Compost exits the worm through its tail end.

Setting up your worm compost bin

Your worm compost bin should consist of at least two compartments; a lower collection area for the liquid and an upper composting area where your kitchen waste goes. The upper level is where the worms actively work.

Worms need moisture, air, food, darkness, and warm (not hot) temperatures. Bedding, made of newspaper strips, compost or leaves, will hold moisture and contain air spaces that are vital to your worm's health. 

You should use red worms or red wigglers in the worm bin. 

When you have your wormery setup with the base layer and worms, cover with no more than 8-10cm layer of kitchen waste and leave for about one week to allow the worms time to settle into their new environment.

Ideal Conditions: 

  • Worms perform best in warm moist conditions. Between 18-25ºC is what to aim for.
  • Their activity declines if they are kept below 10ºC and above 30ºC so be careful where you place your wormery. Basically, in your kitchen, shed or garage where it stays within the required conditions.
  • Don’t neglect your wormery bins if you keep them indoors, as they can sometimes give off bad odours. This is only if you do not keep on top of it.
  • The worms do not do well with lots of acidity and don't like being waterlogged.

What to compost

A variety of any decaying organic matter works best. Here is what you can put in...

  • Any cooked vegetables
  • Any raw veg, except for onions, leeks and garlic that are best used in very small amounts or cooked first
  • All fruit, except citrus peel, which should be limited, or cooked before adding
  • Tea bags, eggshells, coffee grounds and small amounts of bread are fine to add to your wormery
  • Small amounts of newspaper, and cardboard, but not glossy magazines
  • Small amounts of garden waste like leaves and other soft green material

Don’t put in:

  • Dairy products
  • Meat, fish or bones
  • Fat
  • Grease
  • Bigger items of tough garden waste

For best results, add little and often.

  • Chop waste into smaller pieces for quicker decomposition
  • Place the food on the top of the compost or bury the food within the compost
  • If the waste is not being eaten, feeding should be stopped for a few days until the worms start to work through the excess
  • Avoid adding more waste than the worms can cope with. Imagine how it would make you feel :)


The wormery should retain moisture well if the lid is kept on so only add water if the wormery appears dry.

A well established wormery can be left without adding new waste for up to four weeks. However, you will need to drain off the liquid to avoid water logging the worms.

It’s a good idea to fork the compost over gently with a hand fork to check that the worms are present and healthy. I would do this every couple of weeks.

Emptying the wormery:

Wormeries take about 9 to 12 months to create a good set of compost. You must separate the worms before using the compost.

The worms often stay in the area just below the top layer of compost. Just remove the top 20cm layer and use it to restart the wormery again.

Many wormeries use stacking trays for the worms to work their way up. The final compost is in the bottom tray and can be removed. The tray can be emptied and returned to the top of the stack. This is great as you don;t have to sort the worms from the compost!

Worm compost and liquid – how to use:

Your worm compost can be used as a soil conditioner. It is generally rich in nitrogen and potassium.

The liquid drained from your wormery can be used as a liquid fertiliser on your garden plants after diluting with water. Use a rate of 1 part liquid to 10 parts water.