Worm Farming - a helpful home guide

Worm composting is a simple way to recycle your organic kitchen waste, and return valuable nutrients to your garden. Worm farms can take purely kitchen waste, without needing garden waste mixed with it. Other advantages of worm farms are the rich vermicast compost they produce, and their ability to digest paper. In a two person household, 1000 red or tiger worms are enough to digest food scraps. The castings take about seven weeks to be ready to use on the garden, which is quicker than compost bins.

Earthworms from the garden can also be used in a worm bin but don't process food as quickly.     Compost Vouchers Tasman District and Nelson City Councils want to encourage residents to use worm bins instead of throwing scraps in the rubbish because it saves space in the landfill and improves the environment. For these reasons they both provide a $15 subsidy when residents buy worm farms from approved outlets. Please call in to the Council office for a compost bin coupon before purchasing a worm farm.

Create Your Own Eden

Tasman District and Nelson City Councils have joined the national Create Your Own Eden programme.  This programme provides resources and a website to provide you with all the information you need to know on how to make great compost, improve your soil and produce fantastic fertilisers for your plants, veggies and garden all for free. The site covers traditional composting using a heap or bin, vermiculture or worm farming, and Bokashi.  The Create Your Own Eden website and associated resources is available from here.

How to make a worm bin

1. Buy, recycle or make a suitable container (wood, plastic or metal).
2. Drill or punch a few holes in the bottom of the container for aeration and drainage.
3. Place moist bedding (shredded newspaper or similar) in the worm bin, plus one or two handfuls of coarse sand or top soil.
4. Bins should be raised up on bricks or wooden blocks to aid air circulation and drainage. By placing a plastic tray underneath to capture excess liquid, you can obtain an excellent liquid plant fertiliser - use diluted at the rate of 1 part liquid to 10 parts water.
5. Add tiger and/or red worms (1000 or so). Tiger worms and red worms can eat as much as their own weight per day. That means that 1000 worms can eat about 400g per day of food waste.
6. Bury kitchen waste (vegetable and fruit scraps) just below the surface of the bedding preferably spread around the bin. The worm population will steadily increase. In ideal conditions they can double their numbers every 40 or so days.
7. Cover with sacking or a loose fitting lid that will keep the material from drying out and provide a dark environment for the worms.
8. Additional fresh bedding should be added at least every two months.
9. Harvest compost (worm castings) after 3 to 4 months and feed your plants.
10. Top up bin with fresh bedding to replace the compost removed.

Feeding

Worms will eat most vegetable and fruit scraps, shredded paper, tea bags, tea leaves, coffee grounds, crushed egg shells, bread scraps, cereal, cottage cheese, plate scrapings and biscuit crumbs.

Dairy products may also be used, but feed in moderation. Meat and fish scraps may also be used but are not recommended until you are familiar with worm composting.

Foods to avoid are citrus, onions, garlic, garden waste and grass clippings (garden waste is best dealt with by conventional composting methods), fats, cooking oils and oily foods (these create slimy conditions, odour and fly problems) and chicken manure.

Tips

1. Add food regularly rather than in large quantities.
2. Chopping or mincing food scraps before feeding speeds up the composting process.
3. Crushed egg shells provide sufficient calcium to stimulate earthworm reproduction and activity.
4. Worms don't like an acid environment so a monthly sprinkling of dolomite or garden lime is desirable.
5. Semi-mature compost and aged manure provide a source of decomposer micro-organisms which help to soften the food for the worms, as well as providing additional food.
6. If bins are outdoors, protect from full sun in summer, and keep well insulated with packaging material, carpet or something similar, in winter.

Using the worm compost

Finished worm compost is nutrient rich, so it is excellent for topdressing container plants and as an ingredient in potting mixes. It can also be used in the garden to condition the soil every time you plant (a handful mixed into the soil when transplanting vegetables etc gives plants a good start). Use in small amounts.

Compost used as part of a potting mix or as a topdressing around potted plants should not contain worms as they tend to upset the functioning of the potting mix.
 

Download resources

For further advice on how to look after your worms and a poster descripting the process download the files below.