Tips for Choosing the Right Mulch

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How to Choose the Most Suitable Mulch

STEP 1       >> WHY MULCH?

Water Retention
Mulch works like a blanket over the soil and protects it from the drying effects of the sun and wind. It also helps to keep the soil cooler in summer and warmer in winter. Moisture stays in the soil longer which means less watering.

Weed Suppression
Mulch helps to eliminate low weeds by preventing light from reaching them.

Improves Soil Structure 
An organic mulch encourages worms and other soil organisms back into the soil, as they feed on it. As it passes through them, it is further enriched and spread through the top layers of soil. This increases the soil fertility and causes soil particles to clump together which in turn creates greater air spaces. Organic mulch leads to healthier, more open and well drained soil.



Organic Mulch
There are many forms of Organic Mulches, as it refers to any mulch made from matter which was once alive or part of a living thing. Over time they break down into humus – the vital ingredient in fertile soils.

Examples include compost, manure, lucerne, straw, leaf litter, shredded garden waste, grass clippings, sawdust and bark chips.

Inorganic Mulch Inorganic 
Mulch do reduce water loss and suppress weeds, however they do not improve soil structure or add any nutrients to the soil. Examples include gravel, pebbles and plastic.



Apply new mulch at least once a year, after weeding. It should be applied around the base of the plants to a depth of 75mm. Always apply mulch over moist soil and water in the newly laid mulch to settle it in. 

 Keep mulch clear of the trunk to avoid collar rot. 

 It's best to apply organic matter when it is old or rotten, not fresh or green. Fresh/green mulch can be harmful as they burn or take nitrogen from the soil.



Texture – Fine mulch that mats together well. 
Advantages - Relatively cheap. Gives nitrogen back to the soil. High water retention property. Good for smothering weeds. 
Disadvantages – Can contain weed seeds that may germinate. 
Colour – Can vary, but becomes uniform once exposed to sun. 
Life – Lasts for 3-4 months approx.

Texture – Similar to light straw. Slightly coarser and dustier than Lucerne. 
Material – The remains of the pea plant after harvesting. 
Advantages - Relatively cheap. 
Disadvantages – May contain pea plant seeds that may germinate. 
Colour – Pale yellow 
Life – Lasts for 3-4 months approx.

Texture – Larger strands than Lucerne or Pea Straw.
Material – Leftovers from sugarcane after processing. 
Advantages - Weed free as processing removes many weed seeds. Economical mulch. Binds to the soil making it ideal for controlling erosion on sloping sites. 
Disadvantages – Larger strands can make it more difficult to apply around smaller plants and seedlings. Can be dusty and not as high in nutrient content. 
Colour – Pale grey 
Life – Lasts for 3-4 months approx.

Texture – Can range from fine (5mm) to very coarse (40mm) 
Material – Recycled product for mplantation timbers, green waste or post consumer wood waste. 
Advantages - Decomposition is slow, the larger the wood chip, the longer the mulch lasts. Blends well with native gardens. 
Disadvantages – Does not add any nutrients to the soil and can cause nitrogen drawdown issues. 
Colour – Variety of colours available – browns, reds, blacks. 
Life – Larger chips can last up to 2 years.

Texture – Huge range of sizes and textures available. 
Material – Decorative Pebbles. Beach or River Pebbles. Gravels. 
Advantages - Long term mulch alternative which never breaks down. Can make a striking statement. 
Disadvantages – Does not add any nutrients to the soil. High cost compared to organic alternatives. 
Colour – Variety of colours available – whites, greys, blacks, browns, reds, yellows, mixed. 
Life – Long term, as they never decompose.