Main Content Anchor

Worm Farming Guide

Building a Worm Farm

  1. Choose a nice spot for your worms to live. Make sure the spot is not too hot or cold. If you use polystyrene boxes, you will need two of them with one needing a lid.
  2. Poke about twenty holes in the bottom of one box. Put the lid on the box with hole and place this box on the box without the holes. The bottom box will catch the liquid produced by the worms (worm tea).
  3. In the box with the holes or one of the trays in the worm farm, place about 10cm of bedding. Use a combination of shredded paper, leaves and finished compost as a bedding layer, around 10-15cm deep. To this you should add about 1,000 worms (check the Yellow Pages under Worm Farms, or the Australian Worm Growers Website to buy them). The worms used for worm farms are called compost worms, tiger worms or red wrigglers. They are different than the usual earthworm which you should not put into your worm farm.
  4. Cover the bedding with a layer of hessian, newspaper, carpet etc. This will keep the worm bedding dark and moist.
  5. Once the worms have burrowed into the bedding (two to three days) you can start adding small amounts of kitchen scraps. Worms eat vegetable and fruit peelings, tea bags and coffee grounds, as well as some paper; however shred scraps first to ensure easy digestion. Avoid feeding your worms meat and oily foods such as dairy products, or acidic foods such as citrus or onion. At first only add small amounts, once the worms have finished most of their previous meal.
  6. Your worms should produce a rich, soil-like substance called "castings" or "vermicompost", which makes a great fertiliser for potted plants, a potting mix for seedlings or top-dressing for your yard. To harvest your castings, move them to one side of the farm and add new food to the other side. Soon your worms will migrate into the food pile, and it will be safe to remove your castings. In addition, the liquid which is called 'worm tea' that collects in the bottom box can be used as a liquid fertiliser, once it has been diluted. It should be diluted at about 1 part worm tea to 9 parts water. As your plants get used to the solution the strength can be increased.

Helpful Hints

  • Keep the worm farm damp but not wet. Water every so often or as required.
  • If your worm farm smells you're probably just feeding them too much, or giving them too much water. Only feed the worms small amounts at first, when they have almost run out of food, and gradually build up to larger portions.
  • If cockroaches and ants invade your worm farm keep a lid on the farm or cover it with hessian. If your farm sits on legs you can also place each leg inside a bowl of water to keep ants out.
  • If your worms will not breed you may need to keep the farm in a shadier or cooler (around 18-25 degrees centigrade) location or keep it more moist (although not too wet).
  • Acidic conditions can be caused by too much sugary food, such as fruits, and grains. Sprinkling some dolomite, wood ash or lime on the farm can help solve this problem.


(adapted from RELN Plastics) 

How much do worms eat? 
This depends on how many worms you have. Mature worms (which can be identified by the ring shaped swelling around their body), can eat up to half their own body weight every day (approx. 250 grams of scraps). 

How can I help the worms to eat more? 
- Mash, blend, or food process scraps 
- Maintain temperature to around 24 degrees Celsius 
- Avoid acidic foods. 

What should I not feed the worms? 
- Manures 
- Acidic foods (onions, citrus, garlic, shallots) 
- Garden waste 
- Dairy products 
- Meat. 

Should I add water to the farm? 
Watering will enhance the production of liquid fertiliser. Food wastes are about 80% water, which is released as the worms break them down. If you pour some water over the system every couple of weeks you will have a constant supply of liquid fertiliser. 

Will I get many worms? 
No, you can never have too many worms. Worms self regulate their population according to available space and the amount of food you give them. 

Can I put worm farm worms in the garden? 
Worm farm worms require moist conditions all year round, and do not tunnel deep to find moisture. They can only be useful in the garden if you have a thick layer of mulch. 

It's raining and the worms are gathering in the lid - what do I do? 
This is a response to the change in the weather. Worms move up into the lid before it rains to avoid drowning. Move the system out of the rain and replace the worms in the bedding. 

Why are the worms not moving from the lower levels to the top working tray? 
You may have added new food before the worms have eaten the previous food. This leaves uneaten food through the system and causes a reluctance by the worms to migrate upwards whilst they can still access food in the lower layers. Before adding new trays stop feeding the worms for at least a week to ensure all existing food has been eaten. Also, the level of castings in the working tray needs to be high enough for the worms to pass easily up to the next tray. 

Do severe temperatures harm the worms? 
Worms will tolerate a wide temperature range from approximately 10-30 degrees Celsius. If it gets much hotter than this, move the system into a shady, cool position. Take the lid off and hose down the system (making sure the tap is turned on to allow the liquid to drain out). In very cold temperatures, cover the system with some old carpet, underfelt, blankets, and hessian to keep warmth in. Feed the worms more food, which will create some warmth as they decompose. 

How do I keep ants out of the worm farm? 
Ants will enter the system if it is too dry or acidic. Add water to raise the moisture levels and some garden lime to where the ants are gathering. To stop them from getting into the system, place the legs of the system in a container of water or rub Vaseline on the legs. 

Will the worm farm attract flies? 
Sometimes small vinegar flies get into the system, however they will not do any harm. If larger flies are present slow the rate of feeding. 

How can I get rid of maggots? 
Maggots appear due to decomposing meat being present in the worm farm. Avoid meat in your worm farm. To remove maggots place bread soaked in milk on the surface. The maggots will be attracted to it and you can remove them after a couple of days. 

Will the worm farm smell? 
Your worm farm should only smell if there is a lot of uneaten food built up in the system. Stop feeding the worms, add some garden lime and stir the top tray lightly to aerate the mixture. This will allow the worms to move through it more easily. Start feeding again when all smells are gone.

Last updated on 13 June 2015