DPM on breeze block flower beds...

any suggestions on how to fix damp proof membrane to inner side walls of flower beds made with breeze blocks?

Secondly, would anyone use dpm in the flat of the beds after hardcore and before soil / compost layer?

 

Simplest way would be to hold it in place while filling with soil/compost the soil/compost holding it in place, or try galvanised nails to see if they will hold in the blocks, another way would be to drill & screw treated wooden batons (or galvanised, aluminium strips) over the dpm to hold it in place.

It all depends on what you wish to grow, dpm would not allow for good drainage, you really have a blank canvas so once you decide what you want to grow you can fill with a soil mix to suit.

 

Agree with @mazambo for the dpm, do not line the bottom with it otherwise you will end up with a pond and even worse leaking !

Possibly do the reverse and place, below the level of the blocks, a bottom layer of rubble/ gravel so it drains way from the blockwork quickly.

If you do not mind us asking, what is the purpose of those beds, more for ease of access or to add height to a flat area , etc ?

The garden soil, from what we can see looks ok, or its it really poor builders rubble underneath or prone to flooding etc ?

 

I tend to think you are on a hiding to nothing here, trying to stop moisture from the soil getting into the blockwork is going to be pretty much impossible.
You could try the kind of paint they use for concrete ponds but not sure that would help with moisture coming from below .

I'd leave free drainage at the bottom unless you want a swamp followed by a desert.

 

I did a raised pond which backed on to a brick shed.
so to stop any damp on the bricks I used a thick plastic sheet from the top of the pond well down passed the damp proof course.

I used breeze blocks the heavy type to build the end wall and secured the pond liner under the coping stone, same principal could be used to stop damp to a degree from penetrating the blocks.

I had one of those moments with the pond when I decided to put a Lilly on a couple of breeze blocks, only trouble I used light weight and they floated and I wasn’t expecting that for some reason .