Soil Calculator

How to Calculate Soil for Your Garden

Calculating the right amount of soil for your Australian garden project is crucial for healthy plant growth and avoiding waste. Whether you're creating new garden beds, preparing for turf, or filling raised beds, our soil calculator provides accurate measurements instantly.

Understanding Soil Measurements

In Australia, soil is sold by the cubic metre (m³) or by weight (tonnes). Since soil is heavy, many suppliers price by the tonne. Our calculator provides both volume and weight measurements, making it easy to compare quotes and order the exact amount you need.

Choosing the Right Soil Depth

When top-dressing an existing lawn or levelling minor imperfections, 100mm of soil is usually sufficient to achieve a smooth, even surface. For new turf installations and areas with shallow-rooted plants, aim for 150mm of quality turf underlay to give grass roots the depth they need to establish properly. If you're building new garden beds, creating a vegetable patch, or planting anything with deep roots, you'll want at least 200mm of soil—and ideally more for serious vegetable production or fruit trees.

Types of Soil Available in Australia

Topsoil at 1.1 tonnes per cubic metre is your basic screened natural soil, ideal for general filling, levelling work, and establishing lawns. It contains natural organic matter and is the most economical choice for large-scale projects where premium mixes aren't necessary. Garden mix at 1.0 t/m³ is a step up—a premium blend of soil, compost, and organic matter that's ready for planting straight away and perfect for ornamental garden beds.

For vegetable gardens, veggie mix at 0.9 t/m³ is specifically formulated with added nutrients and improved drainage that edible plants love. Turf underlay at 1.2 t/m³ is engineered for new lawn installations, providing the optimal balance of drainage and water retention that grass needs to establish strong roots. Sandy loam at 1.3 t/m³ drains exceptionally well, making it the go-to choice for native gardens and any plants that suffer in wet conditions. Finally, potting mix at just 0.6 t/m³ is lightweight and designed exclusively for containers—never use it for in-ground planting as it will break down too quickly.

Clay soil at 1.5 t/m³ is the heaviest option, used where water retention is desirable or for specific engineering applications.

Tips for Using Soil

For the best results with your soil project, start by preparing the area thoroughly—remove all weeds and loosen the existing soil so your new material can integrate properly. Always order 10-15% more volume than your calculations suggest to account for settling, especially when filling new beds or trenches. When spreading new soil, work it into the existing ground at the edges rather than creating a sharp boundary, as this prevents water from pooling at the junction. After spreading, water the area thoroughly to help particles settle into place and eliminate air pockets that could cause uneven sinking later.

Soil Delivery Considerations

Remember that soil is heavy—a single cubic metre weighs over a tonne, which has implications for both delivery access and how you'll move the material once it arrives. Check that delivery trucks can reach your property and plan where the soil will be tipped so you're not moving it further than necessary. For large orders, bulk delivery by the cubic metre is the most cost-effective option. For smaller jobs or properties with limited access where trucks can't reach, bagged soil or bulka bags that can be lifted by crane offer more practical alternatives.