How to build an elevated garden bed with sleepers?

[cstiles]

I’m looking to build a few elevated raised garden beds, but I’m not sure how to execute.

I’d like to build a few raised garden bed on our gravel area, as it has the best area for light. The ground is very compacted underneath, it’s unlikely I would be able to get any posts into the ground. I’m hoping to elevate them off the ground by around 400mm, and have the actual bed around 400mm deep, 2.4m long and 0.6m wide, using the sienna micro sleepers.

Any ideas on how to achiever this would be great!

[EricL]

Hello @cstiles 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about building elevated garden beds with sleepers.

I suggest having a quick look at this guide - How to build a raised garden bed by @Adam_W. It's technically very close to what you want to build except that it uses full sleepers at the bottom as both cover and legs. The garden bed is technically just half of the entire structure which you can see in the technical drawing of step one. This is because Adam placed flooring where the soil could sit on.   

The plus side of the raised garden bed project is that it also has a provision for seats which I think are very handy. If you were to modify this design, it would just be a matter of making sure that you have enough legs to support the structure. 

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you have any other questions we can help with, please let us know.

Eric

[Dave-1]

Good Evening @cstiles 

Thinking of how I could build it so its high enough and also solid enough.

I would suggest 3 of H shaped supports (think football posts) where the bed is laid across the bar and the sides attached to the inside of the posts. I would do the attaching via bolts not screws as you can tighten them more so. 

Im not sure what size the micro sleepers you mention are but 40mm or 50mm thick is definently strong enough. Posts id suggest 90mm by 90mm by 1.4m or 1.6m high.

I would also have the posts higher by 600mm then the height of the edge of the bed. This is so you can cover your garden beds in either shade cloth if needed or netting if needed. Also something to consider is a strip of copper tape on the top of the garden bed edge all the way around to stop slugs from easy meals.

Dave

[Nailbag]

Hi @cstiles 

I had a concrete slab in my backyard that I thought prior to purchasing the property was only 100mm thick. I had all intentions to cut it up and remove it. Unfortunately it turned out to be 3 times thicker footing for an old machinery workshop. I eventually decided to build raised vegetable garden beds and turn the inside area into a fire-pit area. The sleepers are all sitting on top, batten screwed together with a plastic liner. I don't have a recent photo but the exposed slab has been semi-paved with small river stones in-between.

The pictures below may help with some inspiration for you own.

Nailbag