Edgings for lawn... "Properly" set?!

Hello everyone,

I want to install lawn edging soon. I have chosen concrete lawn edging that is rounded at the front and back. The reason is that I want to create different curves.

Now my question: What is the best way to install the lawn edging (about 4 cm thick)?

I would prefer to simply lay them in the ground without concrete, gravel, crushed stone, or similar... This would have the advantage that I can make changes very easily and not "contaminate" the beautiful topsoil.

Thanks for your tips.
Best regards, Christian

We made a trench. Put in earth-moist concrete, set the edges in it. Holds. There is a YouTube video about it.

I would prefer to simply lay them on the ground, without concrete, gravel, crushed stone or similar... This would have the advantage that I can make changes very easily and do not "contaminate" the beautiful humus soil.

we did exactly that, also because of quick changes

We did exactly that, also because of quick changes

And does it hold?
Without gravel, sand, or chippings?
The concrete doesn’t get contaminated either, so it doesn’t absorb or soak up and turn brown? If it lies directly in the ‘dirt’?

The problem will only show itself in the future. For now it holds, but the grass will grow into it and lift the mowing edge. Solution: Dig slightly wider than the stones and about 10 cm deeper than the stone thickness. Fill the 10 cm with earth-moist concrete, put the stones in there, on the left and right they will get a back support made of concrete. Let it set, fill the rest of the trench with sand. Now the grass will no longer grow onto it. Because of the concrete.

And does that hold? Without gravel, sand or chippings? The concrete doesn’t get contaminated either, so it doesn’t absorb or soak up and turn brown? If it lies directly in the 'dirt'?

Concrete, whether natural or colored, always gets dirty, a pressure washer only helps briefly, I haven’t experienced grass being pushed up, tree roots are stronger there.