Garden Bed Materials: What Do I Need?
Building a new garden bed is a great way to add colour, structure and greenery to your outdoor space, and the main garden bed materials usually include quality soil or garden mix, soil conditioner or organic matter, mulch, garden edging, decorative gravel or stone, plants or seeds, and a few basic gardening tools. Whether you're creating a small garden bed along a fence or a larger area for vegetables and native plants, choosing the right materials is an important part of the process.
For gardeners looking to build or improve a garden bed, especially in Perth, soil preparation deserves some extra attention. Many Perth gardens have sandy soils that drain quickly and can have difficulty retaining moisture and nutrients, so the soil conditioners and mulch you choose can make a significant difference to plant health and long-term garden success.
This guide looks at the materials you actually need, how to choose suitable soil and soil improvers, which mulches and edging options work best, where decorative gravel fits in, what tools to have on hand, and how to estimate quantities based on your garden type and existing soil conditions.
1. Good Quality Soil or Garden Mix
Soil is one of the most important materials you'll need, and for raised beds, wood is also a common structural choice. The type of soil or growing mix you choose will depend on what you intend to grow.
A general garden bed may benefit from a quality landscape mix, while vegetable gardens and other specialised planting areas may require a mix formulated specifically for growing edible plants. Untreated wood is the most common material for raised beds, with many types used. Pine is a less expensive option that typically lasts for years, while cedar can last twenty years or more. Softer woods have a lower cost but shorter lifespans, though organic wood preservatives can help extend them.
If you're building a garden bed over existing sandy soil, you may also need to improve the soil rather than simply planting directly into it. Adding suitable soil and organic matter can help improve moisture retention, nutrient availability and the overall growing environment.
The depth of soil required will depend on the plants you're growing. Shallow-rooted plants generally require less soil than larger shrubs and plants with deeper root systems.
2. Soil Conditioner or Organic Matter
If your existing soil is poor, sandy or lacking organic matter, a soil conditioner can be an important addition.
Organic matter can help improve the structure of sandy soils, allowing them to retain more moisture and nutrients while still maintaining drainage.
For Perth gardens, this can be particularly useful because water can move through sandy soil relatively quickly. Improving the soil before planting gives plants a better environment in which to establish their root systems.
The right approach will depend on the condition of your existing soil and the plants you intend to grow.
3. Mulch
Once your plants are in place, adding a layer of mulch is one of the simplest ways to help protect the garden bed.
Mulch can help reduce evaporation from the soil surface, suppress weeds and moderate soil temperatures. It can also add organic matter to the soil as some types of mulch gradually break down.
There are many different types of mulch available, including wood chips, bark and other organic materials. The best choice will depend on the appearance you want and the plants you're growing.
As a general guide, mulch is often applied several centimetres deep, while keeping it away from direct contact with plant stems and trunks.
4. Garden Edging
Edging isn't essential for every garden bed, but it can make a significant difference to its appearance and practicality.
Garden edging creates a clear boundary between the garden bed and surrounding lawn, paths or other areas. It can also help keep soil and mulch contained.
Depending on the style of your garden, edging can be made from timber, stone, concrete, metal or other landscaping materials, though pressure-treated wood is a bad choice for edible beds because the treatment process replaces air in the wood with toxic chemicals for preservation. A related point is that newer treatments such as alkaline copper quat (ACQ) still are not considered safe for growing food.
For a more informal garden, you may choose to create a simple curved edge without installing a permanent border.
5. Decorative Gravel or Stone
Decorative gravel isn't necessary for every garden bed, but it can be useful as part of the overall design.
Gravel can be used around the edges of garden beds, between planting areas, or to create paths and other low-maintenance areas. For raised beds, stone is often one of the cheapest options when you can source it from your own property. The downside is that irregular shapes can make construction take more time.
Decorative rocks or stone can also provide an attractive contrast against green foliage and mulch, making it a popular choice for modern and waterwise garden designs.
If you're using gravel as a ground covering, preparing the area properly beforehand is important to help prevent the material from becoming mixed with the underlying soil. Cement blocks are also easy to use for raised beds, last a long season, and can be arranged into different shapes. As cement blocks break down over time, they may raise soil pH.
6. The Right Tools
You don't need a huge collection of equipment to build a garden bed, but the right tools depend on the material used for raised beds as well as the size of the project. Composite lumber combines wood fibre and plastic, is commonly used for decking, lasts longer than untreated wood, and is a durable, less toxic alternative to pressure-treated wood that a lot of people choose. Plastic and fabric kits can also be easy to assemble; plastic raised beds are often durable and inexpensive, while fabric raised beds are made from synthetic, flexible materials. The main issues are that some HDPE plastics can leach chemicals into the soil; food-safe plastics are recommended for growing food, finding food-safe plastic raised bed kits can be challenging, and even good things can break down quickly in sunlight.
Depending on the size of your project, you may need:
Shovel or spade
Garden fork
Rake
Wheelbarrow
Measuring tape
Gardening gloves
Secateurs
Hose or watering can
Level, particularly for formal garden beds
A wheelbarrow can be particularly useful when you're moving bulk quantities of soil, mulch or gravel around the garden.
7. How Much Material Do You Need?
One of the most common questions when planning a garden bed is how much soil, mulch or gravel you'll actually need.
For bulk landscaping materials, you can estimate the volume required using a simple calculation:
Length × Width × Depth = Cubic Metres
For example, a garden bed measuring 5 metres long by 2 metres wide with a soil depth of 0.3 metres would require approximately:
5 × 2 × 0.3 = 3 cubic metres
Material choice affects planning too, because metal raised beds generally last about 10 years and may need replacing over time. Over time, metal can contribute particles to the soil, so they are not the best choice for growing food.
Remember that this is an estimate, and the amount required will vary depending on the material and the finished depth you want to achieve.
It is also worth measuring the area carefully before ordering materials. Buying too little can mean making another trip, while ordering significantly more than required can leave you with excess material to store or dispose of.
Planning Your Raised Beds Garden Bed
Before ordering your materials, think about what you want the finished garden bed to achieve.
Are you planting vegetables? Creating a native garden? Adding shrubs and flowers? Building a low-maintenance garden?
The answer will influence everything from the soil you choose to the type of mulch and edging you use.
For Perth gardens, it is particularly important to consider drainage, soil quality and water retention. Improving sandy soil and protecting the surface with mulch can help create a more suitable growing environment for many plants.
Garden Bed Materials Checklist
For a typical garden bed, you may need:
Quality soil or landscape mix
Soil conditioner or organic matter
Mulch
Garden edging
Decorative gravel or stone, if required
Plants or seeds
Basic gardening tools
With the right materials and a little preparation, building a garden bed doesn't have to be complicated. Good soil provides the foundation, mulch helps protect the finished garden, and thoughtful edging and landscaping materials can give the area a clean and attractive appearance.
If you're unsure how much soil, mulch or gravel your project requires, taking accurate measurements before ordering can help ensure you get the right quantity for the job.
All Sands and Soils in Wangara, WA has everything you need to get started. Order online or come to our depot to pickup; free trailer hire is also available.