Oak Sleeper Raised Beds

[BigMonka]

Hi all,
I'm looking to build some raised beds for the veg in the garden to replace the flimsy ones I did 12 years ago. I want something that looks quite solid and structural so was thinking of using oak sleepers as, despite the painful cost, they will hopefully last as long as might want them. There's a local place that does 240cm x 20cm x 10cm ones which means that three would nicely replace each 2.4m x 1.2m bed (outer dimensions).

I was looking for a way to make the corners look decent and be quite strong so I was thinking of doing half-lap corners with a vertical peg. Like the sketchup model below.
Is this likely to work and look alright? Should I glue the corners as well?
Any advice appreciated!

 

[AndyP]

I don’t imagine they would need gluing as well.

If you fancy doing something different with those corners though how about the half dovetail notch?

This has been in situ now now for nearly six years, no screws, no pegs no glue.
there is a tutorial on how do them here

square hewn log notching.....

square hewn log notching.....

forestryforum.com

After the first one really not that difficult.

 

[BigMonka]

Ooh that looks really nice Andy
I'll have a read of that link and run the option past my wife who is the real gardener here

 

[Malc2098]

Is oak really necessary. There's softwood option from sawmills round here. They must be cheaper.

 

[BigMonka]

Is oak really necessary. There's softwood option from sawmills round here. They must be cheaper.

Good question Malc. Our local place has oak sleepers at £37.50 and a softwood "Pressure treated with Eco-Friendly Tanalith wood preserver" at £21. So yes, they're notably cheaper than oak but with them being in constant contact with soil on two sides I wasn't sure of the longevity of the softwood ones?

 

[AJB Temple]

Oak used to create raised beds will only last well if you treat it and also create an impermeable layer if soil is against it. Wet soil used for growing mediums rots oak more quickly than you might think. This is based on experience of building oak sleeper retaining walls at current house 8 years ago.

Reclaimed railway sleepers (usually soaked in tar) will last a long time, but must be lined to prevent soil contamination.

 

[AndyP]

I lined the one above with a plastic tarp and because I left gaps between each log any moisture trapped between tarp and wood has somewhere to go.

 

[Inspector]

I made 2 foot high planter beds from pressure treated 2 x 4s and treated plywood. I lined them with the dimpled plastic membrane used against foundations here to facilitate drainage. Works well in the planters by allowing any water to drain away.

Pete