How to build raised garden bed with sleepers?

[shazaam]

Hi everyone,

I've recently built three raised garden beds using Sienna-treated pine sleepers (50mm thick). Here are the dimensions of each bed:

• Length: 2.2 meters

• Width: 0.8 meters

• Height: 0.4 meters (2 sleepers stacked)

The sleepers are joined at the corners using timber screws. I'm now trying to determine whether I need to include any additional anchoring or internal bracing.

Specifically:

• Should I install internal stakes or posts at the corners and set them into the ground?

• Do I need any intermediate bracing along the long 2.2m sides to prevent bowing when filled with soil?

I've received mixed advice on this and would really appreciate feedback from others who have built similar beds.

I've attached a photo for reference — keen to hear your thoughts!

Thanks in advance! 

[MitchellMc]

Welcome to the Bunnings Workshop community @shazaam. It's a pleasure to have you join us, and many thanks for your question about building raised garden beds.

I can see that you've used countersunk bugle screws, which are perfectly adequate for securing the corners, and I don't believe you’ll need additional reinforcement or corner stakes to hold the beds in position. You might like to screw the top and bottom layers together, just to prevent the upper layer from shifting if someone leans against it.

The only point of concern is the length. At 2.2m, I wouldn’t necessarily expect bowing, but over time—especially after some wet weather—you might notice the sides start to push out a little. If you'd like to future-proof them, I’d suggest adding a brace across the middle of the long side. Ideally, place it right where the two layers join, so once filled, it will be buried in the soil. You can then screw through the sides of both sleepers into that brace, which will help tie everything together in one go and really firm it all up. 

I've created the render below to illustrate.

Please let me know if you have any questions.

Mitchell
 

[shazaam]

Thanks Mitchell. This is really helpful. Any recommendations how to maintain the borders so as to prevent lawn grass creeping in ? I was initially thinking to leave 20cm at outside perimeter and put mulch. Is this enough or I should install lawn edging ? 

[EricL]

Hello @shazaam 

I propose installing both, the lawn edging will prevent the mulch from mixing into the edge of the lawn. Which means that your lawn mower will not eat the odd mulch patch here and there. 

If you need further assistance, please let us know.

Eric