July 19, 2021 4 min read

Mulch is an unsung hero in your garden and is one of the most powerful tools that a gardener has at their disposal.

What is mulch?

Mulch is a layer of material, such as wood or bark chips, which cover the exposed soil surrounding your plant/s. It’s a powerful tool for water conservation and there’s a load of other benefits too. Read on for more!

How to mulch and what to use

There are many materials you can use for mulching, but the best types to consider using in your garden are from natural and biodegradable materials.

Wood chips, pine bark, leaves, straw, and grass clippings are all examples of beneficial mulch because they decompose and provide many benefits to your soil.

Natural materials that don’t breakdown or which take decades to break down like shells or stones are not considered biodegradable mulch (.. even if they look pretty!)

Steer clear from non-natural materials like plastic, rubber and other refuse items – they’re just an all-round bad idea and a bit of an eyesore too. 

Why mulch matters

Aside from more practical reasons, mulch looks great! It can be the main motivation for some gardeners to use mulch. It can really highlight your lawn for instance and makes the plants in your garden beds look more groomed and cared for. Below are some more practical reasons mulch matters.

To Retain Moisture

A layer of mulch blocks the sun while allowing irrigation to penetrate, thereby keeping soil cooler. Moisture evaporation from soil covered with mulch is typically reduced by up to as much as 50 percent. This insulating barrier also prevents evaporation from heat and wind. Mulch holds moisture in the soil, allowing you to dramatically reduce the frequency and duration of watering. It can make all the difference for the success of new shrubs and trees and encourages established plants to be more drought tolerant.

Suppresses Weed Germination and Growth

A big plus for mulching is that mulch blocks the seeds which blow in on the wind from reaching soil and taking root. With a layer of mulch covering your garden soil, the weed seeds lurking there don’t receive the light they need to germinate either. Weeds are inevitable in the garden, but use mulch properly and you will significantly reduce their numbers. The weeds which do manage to germinate will be smothered by mulch and less likely to become established.  

Helps Moderates Soil Temperature

Many of a plant’s feeder roots (which do the heavy lifting when it comes to taking up nutrients for the plant) grow in the first few inches underneath the soil surface. Those roots remain healthier when they aren’t exposed to extreme heat or freezing temperatures. A mulch layer acts as a buffer against temperature shift.

Reduces Soil Runoff and Erosion

If soil without mulch on it crusts over it becomes impermeable to water and any rain and irrigation will roll over the surface and flow away, carrying with it particles of topsoil and any chemicals or excess fertiliser. Crusted soil like this is also more susceptible to erosion from wind.

Nourishes your plants with nutrients

Over time, natural mulch material breaks down. It feeds the soil food ecosystem which, in turn, feeds your plants. Organic matter also improves soil drainage over time. Native soils like clay and sand are often lacking in organic material and so mulch (and compost) is a great way to improve soil health.

Reduces Landfill Waste

This is one of our favourite benefits of mulching – it reduces waste! Many mulch materials would otherwise end up in the landfill if not used in the garden. Wood products, leaves, and bark are all too often dumped. Instead, think of them as nature’s gifts to gardeners. By using wood mulch products, we’re really helping reduce pollution by cutting down on landfill waste.   

How to Apply Mulch

Once you’ve decided on the type of mulch you’d like to use it’s time to get spreading! 

Here’s our top tips:

  • The sweet spot is a 2-to-4-inch layer. Be mindful not to spread to thick or water won’t reach it. Too thin and it won’t offer any benefits like weed buffering or erosion control.
  • Aim to keep maintaining your mulch at a depth of no more than 4 inches and no less than 2 inches. You will see a notable difference in the health of your plants and soil and a reduction in watering needs.
  • Mulch under plants and trees is a very good thing, but it make sure it doesn’t contact the trunk of trees or shrubs. Why? Mulch right up against a trunk creates a pathway for pests and diseases and can promote rot.
  • Keep the mulch layer pulled back about 2 to 4 inches away from the trunk base.
  • Mulch beneath trees and shrubs should be spread at least as far as the furthest outer reach of the foliage, being sure to reach the root systems fully and protect them.


Mulching is a fantastic way to protect your plants, to reduce watering and retain moisture, it discourages weed growth and creates an attractive and neat looking garden. Whatever your motivation for mulching, be mindful of how you go about it and the particular conditions your plant species prefers before you get stuck in. 

Are you looking for plant shops near you? You can order online at Sunshine Coast Plants to get your plant of choice delivered straight from the nursery to your home. To buy plants online for the Sunshine Coast, Southeast Queensland and NSW areas, shop with us today!

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