Worm farming, or vermiculture, is one of the most efficient and rewarding ways to process kitchen scraps. Unlike traditional composting, which requires outdoor space and regular turning, a worm farm fits on a balcony, in a laundry, or in a small courtyard. It produces virtually no odour when properly managed and creates two valuable products: worm castings (vermicast) and liquid fertiliser. This guide covers everything you need to know to start and maintain a thriving worm farm in Australian conditions.
Why Worm Farming Works
Composting worms are remarkably efficient processors of organic waste. A healthy population can consume roughly half its body weight in food scraps daily. Unlike soil-dwelling earthworms, composting worms thrive in the concentrated organic matter of a worm farm environment.
The worms eat food scraps, paper, and other organic matter, processing it through their digestive systems. What emerges is worm castings—a nutrient-rich material often called "black gold" by gardeners. The castings contain beneficial microorganisms and nutrients in forms readily available to plants, making them superior to most commercial fertilisers.
Choosing Your Worm Farm
Worm farms come in various designs, from simple homemade bins to multi-tiered commercial systems. Each has advantages depending on your space, budget, and waste volume.
Stacking Tray Systems
The most popular design features multiple trays that stack vertically. Worms migrate upward through holes in the tray floors as lower trays fill with castings. This design makes harvesting easy—simply remove the bottom tray when full. Popular Australian brands include Tumbleweed and Maze.
Continuous Flow-Through Systems
These larger systems have food added at the top and castings harvested from the bottom. Best for households generating large volumes of food scraps or for serious gardeners wanting maximum vermicast production.
DIY Options
Effective worm farms can be made from plastic storage containers, polystyrene boxes, or old bathtubs. The key requirements are drainage, airflow, and protection from light and temperature extremes.
For most households, start with a 2-3 tray system. One tray can process approximately 2-3kg of food scraps weekly. You can always add trays as your worm population grows.
The Right Worms
Not all worms are suitable for worm farming. You need specific composting species that thrive in the rich, confined environment of a worm bin.
Recommended Species
- Red Wigglers (Eisenia fetida): The most common and reliable composting worm. Hardy, fast-breeding, and tolerant of varying conditions.
- Tiger Worms (Eisenia andrei): Similar to red wigglers, often sold interchangeably. Equally effective.
- Indian Blues (Perionyx excavatus): Faster eaters but more temperature-sensitive. Best for warm climates.
Where to Get Worms
Purchase composting worms from garden centres, online suppliers, or local councils (some offer subsidised worm farming starter kits). You'll need approximately 500-1000 worms to start—about 250g. The population will double every few months in good conditions.
Never use earthworms dug from your garden. These soil-dwelling species won't survive in worm farm conditions. Always purchase or obtain worms specifically bred for composting.
Setting Up Your Farm
Proper setup is crucial for long-term success. Take time to create the right environment before adding worms.
Location
Choose a spot that's:
- Shaded or partially shaded (worms are light-sensitive)
- Protected from extreme temperatures (10-25°C is ideal)
- Close to the kitchen for convenient feeding
- Well-drained (never sitting in water)
- In garages, laundries, or carports in hot climates
Bedding Preparation
- Fill the bottom tray with moist bedding material—shredded newspaper, cardboard, coconut coir, or aged compost
- The bedding should be damp like a wrung-out sponge
- Add a handful of garden soil to introduce beneficial microorganisms
- Let the bedding sit for 2-3 days before adding worms
Adding Your Worms
- Gently spread worms across the bedding surface
- Cover with a damp newspaper or hessian blanket (worm blanket)
- Close the lid and leave undisturbed for a few days
- Don't feed for the first week—let worms settle into their new environment
What to Feed Your Worms
Worms will eat most organic matter, but some foods are better than others. A varied diet produces the healthiest worms and best castings.
Excellent Foods
- Fruit and vegetable scraps (except citrus and onion)
- Coffee grounds and tea leaves
- Crushed eggshells
- Bread and pasta (in moderation)
- Newspaper and cardboard (shredded)
- Vacuum cleaner dust and hair
Foods to Avoid
- Citrus fruits and onions (too acidic)
- Meat, fish, and dairy (attract pests, cause odours)
- Oily or greasy foods
- Spicy foods
- Garden weeds (may contain seeds)
- Pet waste
Feeding Tips
- Chop or blend scraps to speed processing
- Bury food under bedding to prevent flies
- Feed in different sections to encourage worm movement
- Don't overfeed—if food is accumulating, reduce amounts
- Start slow: a handful every few days initially
- Only add new food when previous food is half-gone
- In summer, worms eat more; in winter, less
- Balance wet foods with dry carbon materials (shredded paper)
Maintaining Your Worm Farm
Moisture Management
Proper moisture is critical. The farm should be damp but never waterlogged. Worms breathe through their skin and will drown in excess water. In dry conditions, lightly spray with water. If too wet, add dry shredded paper or cardboard.
Temperature Control
Australian summers can be deadly for worms. When temperatures exceed 30°C:
- Move the farm to the coolest location available
- Add frozen water bottles to cool the bedding
- Wet down the farm and surrounding area for evaporative cooling
- Avoid feeding—decomposing food generates heat
pH Balance
Worms prefer neutral to slightly acidic conditions. If the farm becomes too acidic (indicated by an ammonia smell or worms trying to escape), add crushed eggshells, dolomite lime, or agricultural lime to neutralise.
Harvesting Worm Products
Worm Castings
In stacking tray systems, the bottom tray fills with castings while worms migrate upward. Remove this tray, empty the castings, and move the empty tray to the top. For other systems, move all material to one side, add fresh food to the empty side, and harvest castings after worms migrate.
Worm Tea (Liquid Fertiliser)
Liquid drains into the collection tray at the farm base. This "worm tea" is a potent liquid fertiliser. Dilute 1:10 with water before applying to plants. Use within a day or two—it doesn't store well.
Troubleshooting Common Issues
Worms Trying to Escape
This indicates environmental problems—usually too wet, too acidic, too hot, or too much food decomposing. Address the underlying cause. Leaving a light on overnight may prevent escapes while you fix the problem.
Vinegar Flies
Small fruit flies are common but manageable. Ensure all food is buried, add a thick layer of paper/cardboard on top, and avoid overfeeding. A piece of fruit peel placed in a jar with vinegar can trap adults.
Bad Smells
A healthy worm farm smells earthy, not foul. Odours indicate anaerobic conditions—usually from overfeeding or excess moisture. Remove uneaten food, add dry carbon materials, and aerate the bedding.
Worm farming requires patience initially, but once established, a farm largely takes care of itself. You'll develop an intuitive sense for your worms' needs. The reward—rich castings and liquid fertiliser—makes the effort worthwhile, and there's genuine satisfaction in watching your worms transform kitchen scraps into garden gold.