Low wall to keep soil in - how to build?

MichaelR

Hello,

So, the Missus is asking for a low wall, to run in parallel to an existing wall. This creates a raised bed to fill with soil. The question: how do I build this.

Blocks are the obvious solution, but unfortunately, as the garden is fully enclosed, they are hard to carry in (one has to go through the house). And I'd need a lot of blocks to put them down horizontally. Or else half this amount to put them down vertically, but then I need a foundation, and that's more stuff to carry and also concrete to mix.

It would be easier to put up some poles and concrete them into the ground - far less concrete needed. But what poles do I use and what do I attach to the poles? Wooden poles, wooden planks - but will this last? Wooden (treated, thick) poles, plastic/perspex walls - but the plastic/perspex will break under the weight of the soil? Concrete poles - maybe I can find short poles, but what goes on them? Metal - but how do I avoid corrosion?

What options should I consider here? Or is "hiring a couple of men or else a crane to bring in the blocks" the only one?

septictank

A few dimensions would help lads in the know.

How long is the garden?

How high and what depth do you want the bed?

looksee

You can make a low raised bed most easily with some 2x10" treated timber (or 3x10 for a belt and braces job). Usually comes in 4m lengths. You will also need some 4x4" timber to cut into approx 18inch lengths to make support posts which you will cement in place. Use either coach bolts drilled all the way through post and plank, or screw in place with decking screws (if its 2x10). Exactly how you go about assembling it depends on what tools and skills you have but it really isn't complicated.

Your only issue may be if you can't thread a 16ft plank through the house so check that first.

The problem with using blocks is that when the job is done they still look like a row of blocks and need some sort of finishing/cladding.

MichaelR

Thanks a lot!

I'll make and post the length measurements tomorrow. As for the height, the Missus wants circa 24 inches ideally, but I guess I can persuade her to do with 20 inches, so two 10-inch planks and longer support posts.

And I can thread a 16ft plank both through the house (did that with a ladder of this kind of length) and over the back wall - getting a man with a van to deliver it is the bigger issue but also doable.

One question, however: is treated timber fine if vegetables are to be grown on the bed? Or might the treatment seep into the soil? (Or maybe I should just cover the wall with a soft plastic sheet on the inside?)

Still stihl waters 3

Treated timber will be fine, there's no danger to the soil, timber is the handiest thing for your job

standardg60

Line the inside of the timber with plastic membrane if you want it to last

looksee

I'd agree about the plastic but I have examples of either way and there isn't any difference as yet. It would help to spread the pressure if you have two planks. Take a few years to rot a length of 2" treated timber - it will rot eventually but you should get a good few years out of it.

If you do two planks high you will need a good few supports as otherwise you could get one shifting different to another and it will look messy. You really don't need that much height in a raised border unless you are making an actual bed that you want high for convenience reasons.