Mulching is one of the simplest yet most effective ways to improve soil health, conserve moisture, and maintain a well-kept garden. Choosing the right mulch, knowing when to apply it, and understanding which plants thrive with it can significantly impact your garden’s success. Below is a comprehensive guide to all mulch related questions.

 

Why Should You Mulch Your Garden?

Mulching helps retain moisture by reducing water evaporation, making it especially beneficial in dry climates. It suppresses weeds, protects plant roots from extreme temperatures and prevents soil erosion. Mulches also contribute nutrients to the soil as they break down, improving soil structure and fertility over time. Beyond its functional benefits, mulch enhances the visual appeal of a garden by creating a tidy and uniform look.

 

Don’t forget to check out our helpful mulch calculator at the bottom of this page!

What Are the Different Types of Mulch?

Mulch can be classified as either organic or inorganic. Organic mulch options include sugarcane mulch, which is fine-textured, easy to spread, and nutrient-rich, making it ideal for vegetable gardens. Straw mulch, such as pea straw, lucerne, or hay, enriches the soil and is beneficial for improving soil quality. Wood chips and bark mulch are longer-lasting options, well-suited for trees and ornamental gardens. Tea tree mulch is a natural choice that retains moisture and repels some pests, while eucalyptus mulch decomposes slowly and is widely available.

Inorganic mulch options include gravel or pebbles, which provide a long-lasting aesthetic but can retain heat. Rubber mulch, often made from recycled tyres, is commonly used in playgrounds. Landscape fabric, or weedmat, is another inorganic option but has several limitations.

2. Lucerne Mulch

Lucerne mulch is fantastic for veggie gardens. It generally lasts about 6 months and will help boost the health of your soil. 

4. Aged Forest Mulch

Forest mulch is a fantastic budget option, especially for large acreage properties. Sometimes called chipper mulch, it is a mixture of fine to chunky pieces of a variety of vegetation.

6. Black Cypress Mulch

If you are after a mulch that will make your planting pop, try black cypress mulch.  A natural black dye is added to give a dark colour while providing all the termite repellent properties of cyrpuss mulches.

8. Hoop Pine Mulch

Hoop Pine mulch is an excellent choice for windy areas and steep slopes as the large curly pieces lock together.

Can I Use Gravel as Mulch?

Gravel mulch is a suitable option for low-maintenance and drought-tolerant gardens. It does not decompose, making it a long-lasting solution, and it provides effective weed suppression when combined with proper soil preparation. Gravel also enhances drainage, making it particularly useful for succulents and plants adapted to dry conditions. However, it can retain heat, which may not be ideal for all plant types, particularly in hot climates.

 

Should I Use Weedmat?

Weedmat or landscape fabric is generally unnecessary. It does not significantly improve weed suppression compared to regular mulching, and it can hinder soil and plant health by reducing water and air access to the soil. Over time, weedmat deteriorates, leading to plastic pollution in the soil. Instead of relying on fabric barriers, maintaining a thick and well-managed layer of organic mulch is a more effective and environmentally friendly approach to weed control.

 

Should I prepare my garden before adding mulch?

Yes, it is essential to ensure your garden bed is free from all weeds and the soil is healthy. If you have existing weeds and apply mulch over the top, the weeds will just grow through the mulch. Before mulching spray or remove all weeds. To improve your soil health, consider adding compost to the soil. If your soil is compacted, aerate the garden bed with a fork.

 

What is the difference between Mulch and compost?

Compost is a decomposed organic matter to help enrich the soil, while mulch is a protective layer on top of the soil to suppress weeds and retain moisture. Compost can sometimes be used as a mulch but predominantly in vegetable gardens and has to be topped up regularly.

 

Can I Use Grass Clippings as Mulch?

While some gardeners recommend using grass clippings as mulch, it is not the best option. Fresh grass clippings contain high nitrogen levels and often include seeds, which can encourage unwanted weed growth. They are better suited for composting, where they can break down effectively.

 

What Is the Best Mulch for Vegetable Gardens?

The most effective mulches for vegetable gardens are those that decompose quickly while enriching the soil. Sugarcane mulch is a popular choice due to its fine texture and nutrient content. Pea straw or lucerne mulch is another excellent option, adding nitrogen to the soil and improving overall fertility. Compost mulch is also beneficial, as it provides organic matter and encourages microbial activity, promoting healthier plant growth.

 

Best Mulch for Termite Control

Avoid using wood-based mulches such as bark chips and pine mulch near homes to minimise the risk of attracting termites. Instead, opt for tea tree mulch or cypress mulch, as these materials are less appealing to termites. Gravel or stone mulch is another effective alternative for termite-prone areas, offering a durable, low-maintenance option.

One option is to use a strip of gravel mulch around the perimeter of your house before transitioning to the much or your choice.

 

When Is the Best Time to Mulch?

The best time to apply mulch would be in spring. The mulch will help insulate and protect plant roots as temperatures increase. Remulching or a topup before winter is also recommended.

 

How Much Mulch Do I Use?

Applying the correct amount of mulch is essential for its effectiveness. A layer of mulch between 5 to 10 cm is ideal for most gardens. Applying too much can suffocate plant roots, trap excessive moisture, and encourage fungal growth. On the other hand, using too little mulch will not provide sufficient weed suppression or moisture retention. Make sure to keep mulch away from the trunk or base of any plants to minimise rot.

 

How Often Should You Mulch?

Mulches decompose over time and should be replenished every six to twelve months, depending on the type used. Regularly topping up mulch ensures that its benefits, such as moisture retention and weed control, remain effective throughout the year. Cyprus and hard wood chip mulches will last the longest and can be replenished every 12 months. Straw muches such as sugar cane will need more regular replenishing.

 

Are There Plants That Don’t Like Mulch?

While most plants thrive with mulch, some prefer minimal or no mulching. Succulents and cacti, for example, do best in dry soil and can suffer from excessive moisture if mulched too heavily.

Bulbs need direct soil contact to sprout properly, so they should not be covered with thick mulch.

Mediterranean plants such as lavender and rosemary prefer well-drained soil and may develop root rot if mulched excessively.

With all plants, you should keep mulch at least 5 to 10cm away from the base of the plant to minimise rot and damage to the trunk.

 

Can I use free mulch from a tree lopper?

Using free mulch from a tree lopper is a cost-effective way to mulch your gardens. Before using any free mulch it is essential to inspect the mulch for contaminants. Letting the mulch decompose for a few weeks before applying it to your garden is also recommended. All mulches should be adequately composted not to cause damage to your plants. Be aware that free mulch may bring diseases from sick trees that have been chopped down.

 

How to calculate how much mulch you need

Below is a calculator to help you calculate the cubic meters you will need for your garden.
To calculate the cubic meters of mulch needed for a garden, you use the formula for volume:

Volume=Length×Width×Depth

where:

• Length is the length of the area to be mulched (in meters),
• Width is the width of the area to be mulched (in meters),
• Depth is the desired depth of mulch (in meters).

Since depth is often measured in centimeters, it must be converted to meters before applying the formula:

Depth in meters=Depth in cm / 100

Example Calculation:

If you have a garden bed that is:

• 4 meters long
• 3 meters wide
• Mulch depth of 10 cm (0.10 meters)

Using the formula:

Volume=4×3×0.10
=1.2 cubic meters

​So, you would need approximately 1.2 cubic meters of mulch.

Mulch Calculator 

To make things easier you can use the calculator below to calculate exactly how much mulch you need.