Worm Farms


So what is worm farming?worm farm

Worm farming is a form of composting, using worms to eat your fruit and vegetable scraps.

Compost worms ingest a large volume of food and create castings. These castings have high nutrient levels and as such are an excellent fertiliser. The liquid residue also makes an excellent fertiliser. It needs to be diluted with water to the colour of weak tea and can be poured directly onto your plants.

Worm farms are ideal for people living in flats, units or houses with small backyards, since little area is needed.

The difference between a regular compost and a worm composting system is that worm castings are the finished product: the nutrients in vermicast are completely plant-soluble (directly absorbed into the plant) as it is aerobic (oxygenated). Regular, anaerobic (non-oxygenated) compost is a nutrient-rich product, but before it can be absorbed by the plants it needs to be further processed by other organisms within the garden.

Compost worms are used in worm farms. These are quite different from garden worms as they move quickly over longer distances in search of food, whereas garden worms hardly leave their tunnel, except during mating season or when flushed out by rain or lack of food.

Three types of compost worms commonly bred for composting are tigers, reds and blues.

Composting with earthworms is called vermiculture.

Attend a workshop

Learn the basics to successful worm farming at one of our free home composting workshops.  For more information on the workshops and to register click here.

Facts about the worm

Knowing a few basics about worms and how they make a compost work will ensure you have a successful system that will keep you recycling at top efficiency indefinitely. 

  • worms are cold-blooded invertebrates - meaning they rely on environmental sources for heat and have no backbone
  • worms breathe through their skin, extracting oxygen from moisture in the soil. A constant supply of fresh water will keep your worms healthy, but don't over water as this will cause stagnancy in the farm and will drown the worms
  • light kills worms. Two or more hours exposure is fatal. Thus the importance of providing a cover such as hessian, carpet or newspaper (needs to be replaced regularly) and this will also protect them from predators and evaporation
  • soil disturbance of any kind is detrimental to worms. "Turning" a worm compost system will disturb the many thousands of baby worms, destroy the burrows and interrupt mating, slowing the rate dramatically. Worms do all the work themselves, very efficiently
  • fresh air is another major requirement. An air-tight lid will suffocate and/or overheat worms. Ensure the system is placed in a shady place in your backyard, in a low light area on your balcony or inside the garage/garden shed
  • worms are hermaphrodites (both male and female in one). They only mate with their own species. They have an innate ability to sustain the optimum population according to the available food supply and space
  • happy worms will chomp (or rather suck) their way through about half their own weight in food each day. That means that 1kg of worms will go through 500g of food once they have adapted to their new environment and food source. This will take up to one week - taking about 3 weeks for the bin to settle in properly.

Setting up the worm farm

  1. Select a container for keeping worms. The instructions refer to the three tiered Worm Factory from Reln.
  2. This system comes with a coir fibre block which acts as the bedding material for the worms. Follow the instructions on the wrapper.
  3. Place the cardboard colour display in the bottom of the first working tray to prevent the coir bedding material from falling through. The worms will eat this in time.
  4. Spread the prepared coir bedding on the cardboard display.
  5. Spread your worms and the contents of their package over the coir bedding. Leave the lid off for a short time whilst the worms enter their new habitat.
  6. Add a small amount of food to begin with until they adapt to their home. Ideally, place two centimetres of food over half the surface area. DO NOT OVER FEED.
  7. Cover the worms and bedding with a moist hessian bag/carpet or wet newspaper. This keeps moisture in, light out and encourages worms to come to the surface to feed. Replace the lid.
  8. Liquid fertiliser drains through the system and into the collector tray. Check and empty regularly, once a week.

Once established

  1. Feed your worms in the First Working Tray and they will produce castings which look like rich dark soil. When the level of castings is 2cm above the moulded line half way up the inside of the first working tray, it is time to move upstairs.
  2. Stop feeding worms for at least one week to allow them to finish off the food in the First Working Tray.
  3. Remove hessian and add the Second Working Tray. Make sure it sits firmly - any gaps and the worms will be unable to move up to the food.
  4. Then place food scraps in the Second Working Tray and cover with hessian and replace the lid. The worms will make their way up towards the food. No need to add further coir for bedding as the worms will make their own bedding as they eat the food now in the Second Working Tray.
  5. Continue feeding worms in this way. When the level of castings reaches 2cm above the line, the majority of the worms will have moved out of the First Working Tray which will be full of rich castings and ready for use.
  6. Empty first working tray and place on top of second working tray. In this way, one working tray replaces the other, and so on.

Overall this should take several months.

Using castings and the liquid

Worm castings and liquid are useful additives to the garden with a neutral pH level of 7.



Plant fertiliserspread a layer of worm castings 2.5cm deep around plants.
Lawn Top Dressing3 parts aged compost to 1 part castings
Seed Raising Mixture3 parts aged compost to 1 part castings
Potting Mix2 parts aged compost, 1 part castings, 1/2 part Vermiculite.
Native and Fruit TreesApply around base dripline and water well (Spring and Autumn)
Liquid fertiliserfrom the collector tray can be used on all plants when diluted 50% with water.


Read more about worm farming on the frequently asked questions page.