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How to build a garden bed

A raised garden bed featuring pink and yellow flowers, green shrubs, and a terracotta birdbath.

Overview

A garden bed lets you grow the flowers, trees, fruit, vegetables and herbs of your choice in your own backyard in the best soil possible. This guide shows you the tools and equipment you need to build one yourself. It also gives you tips about how to keep your sleepers square, the best way to remove concrete footings and the easiest way to dig trenches for your wooden sleepers.

Safety tip: Always wear the appropriate safety equipment (safety glasses, gloves, ear muffs and a mask, for example) and always follow the instructions for the product or equipment. 

Steps

1Choose the right location and measure the space

Start by selecting a flat location that gets plenty of sunlight, as most plants need about six to eight hours of direct sunlight each day. Avoid areas that are too shaded or prone to waterlogging, as these conditions can affect plant growth. Once you’ve chosen the spot, decide on the size of your raised garden bed. Use a tape measure to measure and mark the dimensions on the ground.
A Bunnings Team Member is measuring the space using a tape measure to mark the dimensions for a raised garden bed.

2Place the stakes in each corner

With your measurements marked, it’s time to set the stakes at each corner of your garden bed. Position each stake firmly in the ground, ensuring they are upright and evenly placed. These stakes will act as anchor points for outlining the perimeter, helping to keep your garden bed square and properly aligned. For added stability, push or lightly hammer them into the soil, making sure they remain secure and won’t shift when you attach the string line. Double-check the placement to ensure the layout matches your measurements before moving on to the next step.
A Bunnings Team Member is placing the stakes in each corner using a hammer to mark a garden bed's perimeter.

3Attach the string line to outline the perimeter

Once the stakes are in place, attach a string line between them to create a clear boundary for your garden bed. Keep the string tight and level to ensure straight edges, as this will help guide the construction of the frame.
A person is attaching a string line around the stake in the ground to outline the perimeter for the garden bed.

4Mark the shape with spray paint

To make the shape more visible, use spray marking paint to outline the perimeter along the string line. This will serve as a guide when it’s time to build the frame, helping to keep everything aligned and in place.
A person wearing work boots is marking the ground with blue spray paint to outline the perimeter along the string line.

5Measure and cut the sleepers

Use the tape measure to work out the length of the garden bed and halve this figure, which'll be the length you want to cut the sleepers for the sides of your garden bed.  Mark the length out on your sleepers and cut them to length. You want to cut the sleepers to the same length so that they join in the middle of the garden bed. 

Sleepers being marked for cutting

6Lay sleepers down the sides of the garden bed

Remove the temporary screw you drilled to make the U-shape at one end of the garden bed. Lay two sleepers down one side. Drill a temporary screw to join the sleeper at the other end, so it makes a corner. Use the roofing square to make sure that the corner is square. Once it is square, lay the two other sleepers on the opposite side. Check that all four corners, where the sleepers join, are square. Use marking paint to mark the corners on the outside of the sleepers, which'll tell you where to dig a trench for the sleepers.

A square rule being used to ensure the correct placement of garden bed sleepers

7Remove the sleepers

Once the corners are square, remove the sleepers. A good tip is that as you take the sleepers away, remember where each of them was, so that when you start to rebuild the garden bed each piece goes in the right place.

8Remove the grass

Use a mattock to remove the grass and dig down to the required depth. The sleepers will be sunk, so that 50mm is above the ground. This'll make sure that the grass won't grow back into the garden bed. Make the trench deep enough so that you can also lever up the concrete slab.

The ground around an existing garden bed being dug up to make room for sleepers

9Remove the concrete

Use a crowbar to lever up and loosen the concrete on all sides. Use a sledge hammer or lump hammer to break the concrete into smaller pieces. After the concrete is broken, use the crowbar to also lever up the broken pieces. Put these in a wheelbarrow to take them away. Use the mattock to dig out the rest of the grass and dig a trench for the sleepers to sit in, so that 50mm of the sleeper sits above the ground.

An old concrete garden bed being pried free from the ground with a pry bar

10Screw the ends of the garden bed together

Once the trench is the right depth, start putting the ends of the garden bed together. Use batten screws to join a sleeper on the side of the garden bed to the end. Use two screws, one at the top and bottom of each joint. Repeat this process for the other end of the garden bed. Once you've joined both ends together, have someone help you lift them into place.

Two sleepers being bolted together as part of a garden bed

11Put the sleepers in place

Put the four side sleepers in place. Run a string line from one end of the garden bed to the other, to make sure the sleepers are straight. To do this, drill in a screw at both ends of the garden bed and tie your string line to this. Adjust the sleepers so that they are straight and at the right height. Repeat this process for the sleepers on the other side.

String being used to plot out a garden bed

12Secure the sleepers with stakes

Once the sleepers are straight and at the right height. Hammer in a stake to join them at the centre. Drill four galvanised screws into the stakes to join the sleepers together. Repeat this process where the sleepers join on the other side. Depending on the size of your garden bed, you may need to hammer and drill in more stakes to keep the garden bed secure. Backfill the soil, so that it sits evenly in your garden bed. Now your garden bed is complete, add the necessary compost and fertiliser to help your plants grow.

Metal brackets being used to secure two sleepers against each other

13Freshen up your garden

We've got plenty of other ideas to help you freshen up your garden!

Health & Safety

Asbestos, lead-based paints and copper chromium arsenic (CCA) treated timber are health hazards you need to look out for when renovating older homes. These substances can easily be disturbed when renovating and exposure to them can cause a range of life-threatening diseases and conditions including cancer. For information on the dangers of asbestos, lead-based paint and CCA treated timber and tips for dealing with these materials contact your local council's Environmental Health Officer or visit our Health & Safety page.

When following our advice in our D.I.Y. videos, make sure you use all equipment, including PPE, safely by following the manufacturer’s instructions. Check that the equipment is suitable for the task and that PPE fits properly. If you are unsure, hire an expert to do the job or talk to a Bunnings Team Member.