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How to build a simple raised garden bed

Valued Contributor

Difficulty: Beginner

Raised garden beds give you more convenient and comfortable access to your plants and more control over their growing conditions. Raised beds can also be attractive features in your garden, whether you want to grow vegetables, herbs, flowers or anything else.

 

Building a raised garden bed can be surprisingly easy. Just follow our step-by-step guide.

Video Tutorial

Steps

Step 1

Make sure you choose the right materials for the job. If you plan on growing edibles or will be in regular contact with the timber, make sure it is safe. Use new, untreated hardwood (reclaimed railway sleepers can be chemical saturated) or use pine that has been treated with ACQ or Micropro. Do not use conventional CCA treated pine.

 

For our project, we used one row of treated pine sleepers to create a 200mm high bed. Pine sleepers are the perfect choice as they are affordable and easy to work with.

 

Typically a bed like this would use sleepers cut-to-size for the posts but we decided to make it even easier by using galvanised pre-formed sleeper supports. These allow a sleeper to be dropped in and securely held. They are the fastest and easiest way to build beds and walls.

1. Materials.jpg

Step 2

Next step is to ensure your new garden bed is in the right position. Your bed isn’t something you will want to pull up and move, so take the time to get the position right. If growing vegetables or other sun-loving plants, select a location that provides maximum sun exposure across the seasons. Think about exposure to prevailing winds, too. You can position your bed in a sloping section of your yard, but this means it moves from being simply a raised bed to functioning like retaining wall on the downhill side. In this situation there will be a little extra work in securing the front posts. Finally, remember that the bed will become a fixed part of the landscape, so make sure it’s going to work aesthetically with the rest of your yard and not like an after-thought.

 

2. Choose the right position.jpg

Step 3

Mark for the long corners on one side. You can do this by just laying a sleeper on the ground. Dig the first hole to around 200mm deep. Drop one corner-post into the hole with a maximum of 200mm above ground. Temporarily position a 2.4m sleeper in the slot of the corner-post to check alignment with the second hole. Add concrete to the hole, checking the post is plumb on the front and side as you do so. You can use the sleeper end to mark the spot for your second hole precisely. Remove the sleeper and dig the second post-hole.

 

3. Dig the first hole around 200mm deep.jpg

 

Step 4

Position the second corner-post in the hole. Drop-in a full-length sleeper for spacing and alignment, and check the post is plumb. Put a spirit-level on the sleeper to check the level is correct before concreting the post in place.

 

Cut one 2.4m sleeper in half. Position one half sleeper in each corner-post. Measure from the inside corner created to the end of the opposite half sleeper and note the length. Reverse this and compare the lengths. This is called checking the diagonals. If they are the same then your sleepers are correctly positioned at a right-angle. If not, adjust until they are the same and then mark for holes on the ends. Excavate holes and repeat the process for corner-posts, checking diagonally again before concreting.

 

4. Check the diagonals.jpg

 

Step 5

Drop the final full-length sleeper into place between the posts. Work your way from corner-to-corner checking the sleeper height and add one fixing screw through the corner-post to each sleeper. Only add one at this stage to allow for adjustment at the other end. Once each is set at correct height and secured with one screw, go back around and add a second to lock them in place. You may find it easier to pre-drill the steel before sinking screw in.

 

5. Drop the final sleeper into place.jpg

Step 6

Cut weed-mat into strips around 400mm wide and to suitable lengths for each side. Lap these around two-thirds of the way up the sides of the bed and use a staple gun to secure. This will stop any soil from moving out beneath the sleepers and prevent grass from running into the bed.

 

6. Cut weed mat into strips and staple to secure.jpg

Step 7

Find the centre of the long sides of the bed and mark each side at that point. Measure the distance between the inside faces. It should a little over 1200mm. Check the distance on one end to make sure the centre has not bowed. Cut the remaining sleeper to suit the distance. This is fixed from side-to-side across centre with 100mm screws as a brace to prevent the long panels bowing outwards over time.

 

7. Fix a brace to prevent bowing.jpg

Step 8

Ensure the weed mat is fully extended into the bed, not tucked under itself, then start laying newspaper. Wet it slightly first in a bucket to prevent it blowing away as you work. Cover the entire base to at least eight sheets thick. This will be enough to supress any existing grass until it dies back. The paper will then compost down into the soil.

 

8. Use paper to supress grass and weeds.jpg

Step 9

Position the remaining sleeper as a ramp on the side of bed and then start wheelbarrowing in the soil. Level the soil as you go to help avoid air pockets. But avoid compacting excessively – just lightly tamp down.

 

9. Start filling the beds with soil.jpg

Step 10

Plant your new garden bed. We used a selection of semi-advanced and seedling sized vegetables. If you are putting in any plants that require stakes as they grow, such as tomatoes, put the stakes in at planting time rather than hammering through roots later on. Water well then spread mulch before watering again. Your bed is now complete!

 

10.1 Plant your new garden bed.jpg  10.2 Your bed is now complete.jpg

Materials

To create a 2.4m x 1.2 bed on flat ground, you will need:

 

  • Four 2.4m x 200mm x 50mm sleepers (ACQ or Micro-shades/Sienna)

  • Four Retain-It 450mm corner-posts

  • Four bags of quick-set concrete (add extra and use high-strength for sloping sites)

  • 255mm galvanised hex-head timber screws

  • 100mm Climacote bugle-headed batten screws

  • Weed mat

  • Newspapers

  • Bulk soil suitable for the plants you want to grow

  • Lucerne for mulch

Tools

  • Measuring tape

  • Long and short spirit levels

  • Post hole shovel or digging spade

  • Drill-driver with suitable bits

  • Power saw or handsaw

  • Wheelbarrow

  • Staple gun (optional)

Images

1. Materials.jpg

2. Choose the right position.jpg

3. Dig the first hole around 200mm deep.jpg

4. Check the diagonals.jpg

5. Drop the final sleeper into place.jpg

6. Cut weed mat into strips and staple to secure.jpg

7. Fix a brace to prevent bowing.jpg

8. Use paper to supress grass and weeds.jpg

9. Start filling the beds with soil.jpg

10.1 Plant your new garden bed.jpg

10.2 Your bed is now complete.jpg

12 Replies
New Contributor

Hi Jason,

 

This is fantastic! I am going to give this ago. Stay tuned. 🙂

 

Kind Regards

Mystique

Community Manager
Community Manager

Great! We look forward to seeing what you can achieve @Mystique

 

Don't hesitate to post if you need a hand with anything. 

 

Jason

 

New Contributor

Great. Will Bunnings be able to cut the sleepers at the store? I need 3 cuts of 1 sleeper of 2.4m.

Bunnings Team Member
Bunnings Team Member

Welcome to the Bunnings Workshop community @deeguy. It's fantastic to have you join us and many thanks for your question.

 

Many of our stores offer a cutting service which can be used to cut treated pine sleepers to length. I would advise contacting your local store prior to going in to confirm their saw is capable of cutting sleepers.

 

Are you planning on making a raised garden bed? It would be great to follow along with your project and we'd encourage you to let us know if you need any assistance or if you'd like to share it with the community.

 

Mitchell

 

 

 

Bunnings Team Member
Bunnings Team Member

@deeguy,

 

I've made contact with your local stores and they do offer a cut to length service on treated pine sleepers.

 

Please let me know if you need further assistance or had any questions.

 

Mitchell

 

New Contributor

@MitchellMc Thanks for you assistance. I will start this and post updates with pictures soon. The idea of using Retain-It 450mm corner-posts is awesome. I will also use them and see how that goes.

New Contributor

What is the best way to protect the wood in garden beds as it will be exposed to water and wet soil? Is using something like "Builder's film" or "Consolidated Alloys 150mm x 10m Polycourse" on the inner sides a good idea? or maybe some kind of sealant ?

Bunnings Team Member
Bunnings Team Member

Hi @deeguy,

 

The timber slabs you have purchased are H4 treated pine. H4 treatments are suitable for use in situations where the timber is in contact with the ground or is continually damp. As you can see in the article, Adam_W is only using a filter mesh and no additional protection is necessary.

 

Mitchell

 

New Contributor

Hi, what is the required distance between a raised bed and a weatherboard house please? It's in a warm sunny spot on sandy soil, will 10cm be enough to prevent damp issues?

Bunnings Team Member
Bunnings Team Member

Welcome to the Bunnings Workshop community @keridwyn. It's great to have you join us and many thanks for your question.

 

Housing is generally built to withstand surface water being absorbed into timberwork and this is achieved with a damp course layer and water-resistant cladding.  In saying that, ten centimetres is not a lot of room and depending on how you are irrigating the garden you might end up creating a humid and damp area close to a wall.

 

I'm not aware of any regulations on how close a raised garden bed can be to a house wall, but as a rule of thumb, you'd want it as far away as possible. I would advise any watering done to the garden bed should be directed at the individual plants and not sprayed over the side of the house as well.

 

If you haven't already you might be interested in checking out our Top 10 most popular raised garden beds for some inspiration with your project.

 

Let me also mention the very knowledgeable @Adam_W  to see if he has any concerns with the placement or would like to join the conversation.

 

Mitchell.

 

Newbie

I love the look! 

I want to make ome for myself but need non treated raw materials. 

Any reccomendations? 

 

Bunnings Team Member
Bunnings Team Member

Welcome to the Bunnings Workshop community @Ayse. It's fabulous to have you join us and many thanks for your question.

 

As @Adam_W mentions, an untreated hardwood would a suitable choice of materials. Our 200 x 50mm 2.4m Hardwood Sleeper is available to be special ordered into stores.

 

There is also the concrete sleeper range if you didn't want to use treated timber for your project.

 

For some inspiration, you might like to check out our Top 10 most popular raised garden beds and these previous discussions: Rustic railway sleeper garden bed by @ProjectPete and What type of timber for a garden bed? by @yana

 

We look forward to hearing more about your raised garden bed project and we'd encourage you to let us know if you need assistance or would like to share it with the community. 

 

Mitchell

 

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