We dug trenches all around the edge of the raised beds we built last year. Then we found some of the rigid log edging, about a foot tall, sunk this into the trench and used some metal fixings from local diy store to fix them together at intersections along the joins and corners.

Then we filled them with topsoil & planted.

So far they have stood the test of time well, although we are going to have to top the soil up slightly.

It was cheap to do, (we got the edging from a Homebase that was closing down so only cost us £1 each!, and easy to build.