Change borders (loose stones) into part of lawn

[DavidSWP]

Hi,

My back garden has some borders filled with pebbles and I want to just make them part of the lawn. I was expecting only a couple inches of pebbles but they actually go down about 8 inches, below that appears to be sand. I've dug about 3" of the pebbles out already. What would be some options for doing this? Do I need to remove all 8" of pebbles and fill with something(?) before topsoil+seed or turf?

 

[blightymam]

For grass to grow strong and healthy, I would dig down the 8" and remove as many of the stones before filling with topsoil then laying turf or seed. Too little soil underneath the grass will make it weak.
Also, stones tend to come to the surface, drip by drip (normally in winter). A weed membrane could slow that down if really can't be bothered to remove the stones, but you'd have to make sure it's a very good quality one as cheaper ones tend to rip with stones.

 

[r896neo]

The stones are in that depth because they are acting as a drain for the retaining wall. Removing them all and throwing topsoil in is a bad idea and may damage the wall in the longer term.

Remove the stones down about 8'' as blighty suggested but i would avoid any kind or membrane as it will impede drainage a bit. Try to keep a layer of stones tight to the wall almost right up to the surface. Do this by placing a board of some sort about 4 inches away from the wall and fill the grass side with soil and the wall side with stones. then pull the board out when your done.

On top of the stones put maybe 2'' of soil so the grass takes right in to the wall.

 

[DavidSWP]

Thanks for the advice. Actually, now I've excavated it a bit more, I'm not sure if there was a lot of logic behind what was done originally. At one side the pebbles do go down about 8 inches and under that there is sand. But further along, the pebbles are only 2-3 inches and under that appears to be an old weed barrier with soil under it. Its also liberally strewn with very large cement building blocks and large pieces of slate. It looks like it was just filled up with whatever left over junk was at hand.

Now I have another problem - I'm planning to put a fence on the near side of the retaining wall because we have a toddler and don't want them falling off. I've got some of those fencing post holders with 60 cm spikes on the bottom, but I think I'm going to have problems sinking them in because there are so many cement blocks and other large objects there.

I've removed quite a few of the blocks, but are these of any value for drainage? I can imagine how small/medium size stones would help, but not sure about the blocks which are about 50 cm x 20 x 20.

 

[r896neo]

When retaining walls are built in conjunction with building work like an extension etc any old rubble/ hardcore get thrown in to fill up the hole. As long as its free draining thats fine, technically doing it properly would see it all as 20mm gravel or similar.

I would sooner concrete your fence posts in but make sure your fence is low (less than 4 feet) and has gaps to let air through as your relying on the wall for strength and the fence will act as a sail and could pull the wall over.