ᐅ How can I fence off the slope?

You still need an 80mm (3 inch) fall protection barrier there. A simple wire mesh fence will do. On the slope in front, avoid grass and use ground cover plants that hold the soil in place. Grass is too steep there; you would need a two-stroke mower, otherwise the oil lubrication will fail. But grass would also work then. K.

So a 60cm (24 inches) height difference over 80cm (31 inches) length, then the L-shaped concrete block, and then another 80cm (31 inches) drop.

That means a 75% slope or 37 degrees. Am I understanding this correctly?

Then the 1.2m (4 feet) double wire mesh fence will be placed on the L-shaped concrete block.

The lawn slopes 30-40cm (12-16 inches) over 8m (26 feet). My robotic lawn mower can handle that as well.

By lawn, I only meant the last steep section before the L-shaped retaining wall.

Nordlys schrieb:
You still need an 80mm (3 inch) fall protection barrier on that. Just use a chain-link fence. On the slope in front, don’t plant grass but ground cover plants that hold the soil. Grass is too steep there; you’d need a two-stroke mower, otherwise the oil lubrication will fail. But grass would also work then. K.

Or self-propelled 4-legged mowers!

Domski schrieb:
Or self-driving four-legged mowers!

Yes, ground cover plants will probably go on the slope! Something that doesn’t require mowing. Landscape fabric and decorative gravel are out for aesthetic reasons (gray on gray), even though they would be low-maintenance. I can’t say yet how steep the slope will be. The area has been shaped, but the topsoil is still missing. It might end up being 1.60m by 0.80m (5 ft 3 in by 2 ft 7 in) or just 1.20m (4 ft).

I never really thought of the fence as a necessary fall protection.... hmm, so the fence will 1. probably have to be installed, and 2. sooner than expected!