Edging is the best way to keep the separate areas of your landscape well-defined, and will give garden beds a neat, well-planned appearance. Edging is also the best way to keep grass from expanding into your garden beds, which will make weeding easier. Edging should be carefully planned according to the style of your landscape, and should be carried out in a way that will be easy to maintain once the initial edge is created.
Outline the edge of the garden bed with a garden hose. You can also draw a line with powdered lime or a paint devised for grass.
Dig a 3 to 4-inch trench along the outline with a half moon edger or a flat spade. The work will be easier if the tool is sharpened.
Pull up the clumps of turf as you dig. Shake the excess soil into the garden bed and toss the clump of grass into the compost pile.
Re-trim the edges each year, and during the year as needed. Keep the edges neat with a weed trimmer.
Dig a larger trench and install flat bricks or pavers if you prefer a physical barrier. Be sure to lay them in such a way that the mower will easily go over the top.