Any material applied to the soil surface to retain moisture, moderate temperature, suppress weeds, and improve soil health as it decomposes. Organic mulches (straw, wood chips, compost) are preferred for food gardens.
Mulch is one of the most valuable techniques in Australian gardening, particularly important given our variable climate and often harsh conditions. Organic mulches such as wood chips, straw, aged compost, and shredded leaves break down over time, enriching your soil with organic matter and improving its water-holding capacity. This is especially beneficial in dry zones and during the hot months of December to February when moisture retention is critical.
The ideal mulch depth is 5-10 centimetres, applied around plants but kept clear of stems to prevent rot and pest issues. In tropical and subtropical zones (zones 10-12), mulch helps regulate soil temperature during intense heat and heavy rain periods. In cooler southern zones, mulch provides insulation during winter months (June-August) and suppresses winter weeds. Inorganic options like gravel and pebbles suit xeriscaping and low-maintenance gardens but don't improve soil structure.
You can source mulch from Bunnings or specialist landscape suppliers, or make your own from garden waste using a mulcher. Refresh mulch annually or as it breaks down. Eucalyptus bark is popular for Australian gardens as it's locally available and aesthetically suited to native plantings. Avoid mulches that compact easily or contain weed seeds. Apply mulch in autumn (March-May) or spring (September-November) for best results, giving plants time to establish before extreme seasons.