by Russ Grayson, updated May 2020.
Composting turns our kitchen and garden wastes into plant food:
- almost 50 percent of waste produced in the home can be composted — composting is a do-it-yourself approach to reducing our waste
- making compost avoids the need to buy fertiliser.
You can make compost in commercially available plastic compost bins, in large bays, or heaps.
Community gardeners need large bays to produce enough compost for the garden.
ADAM is a simple acronym to remember how to make great compost. It covers the key ingredients and conditions for success.
Aliveness — anything that is or has been alive is suitable for making compost; people new to composting might avoid meat waste as it can attract vermin such as rats, if not composted correctly
Diversity — a mix of materials ensures that the correct ratio of carbon (brown) to nitrogen (green) materials is included; nitrogen is a plant nutrient
Aeration — air is necessary for the decomposer organisms to break down the organic materials
Moisture — necessary to decomposer activity, a moisture level of less than 40 percent slows activity while more than 60 percent reduces the availability of air and produces a smelly compost. Keep the compost moist but not saturated.
The Many Uses of Compost
Compost can:
increase the availability of the nutrients our plants need to grow strong and healthy — compost is a fertiliser
retain moisture by adding organic matter to light, sandy soils
increase drainage in heavy, clay soils
increase aeration in compacted soils
reduce the extent of temperature extremes in soil, keeping soils cooler in summer and warmer in winter
help form aggregates in poorly structured soils.
How to Use Compost
make potting mix instead of buying a commercial product: try one third sifted compost, one third coarse sand for drainage and one third coconut fibre for water retention
make a seed raising mix: try 50 percent sifted compost for water retention and 50 percent coarse sand for drainage in places with hot summers
use as a mulch for your pots and around vegetables and fruit trees — keep it clear of the stems and tree trunks to avoid collar rot.
Compost is ready to use when it has broken down to a fine, crumbly texture, when it is black in colour and has an earthy smell.
Common Problems and Solutions
foul smell: too wet, not enough aeration — add dry carbon materials such as leaf litter and turn; cover when raining
slow decomposition: insufficient nitrogen material; add fresh lawn clippings, kitchen scraps, animal manure, blood and bone fertiliser; could also be insufficient air — turn the heap
ants: check moisture; add water if needed; cover food scraps with grass or newspaper; turn the compost
flies: may be anaerobic (decomposing without air) — turn; add dry carbon or course materials; cover heap with hessian or similar material
maggots: remove meat from compost; cover maggots with lime; add soil to top of compost and turn heap next day
mice/rats: the compost heap is a warm, cosy place to raise young rodents — turn regularly; reduce the amount of bread and meat; always cover food scraps with grass or newspaper.
Stay Well, Stay Healthy
Compost contains living organisms that, on rare occasions, may cause illness. Precautions include:
moistening compost to avoid micro-organisms becoming airborne before working on compost
wearing gloves to protect broken skin
washing hands after handling compost
wearing a dust mask if you suffer from asthma or respiratory disorders
if you handle animal manure, consider vaccination against tetanus
protect yourself from sunburn with suncream and hat
drink plenty of water while gardening.
References
Handreck K, 1993, Gardening Down-Under; CSIRO, Australia
Rutherford, Peter W. & Lamonda, Mary Lou, 1996; The Australian Compost and Worm Book, Apollo Books, Mosman, NSW Australia
Simons, Margaret, 2004; Resurrection in a Bucket; Allen & Unwin, Crows Nest, NSW, Australia.
