This 3-Inch Edging Rule Is a Fail-Safe Way to Keep Grass Out of Your Garden Borders – Do It Now for a Neat Spring Lawn

A garden border full of flowering shrubs and perennials with a green hedge in the background at Walnut Cottage Garden.

Have you ever wondered how professional gardeners seem to have the most perfect edges between their neat lawn and productive flower borders? Well, now you can get the look too, using the 3-inch garden rule for edging – a trick that involves digging a narrow trench to keep the two areas separated.

Even the most carefully planned garden ideas can lose some of their impact if the boundary between lawn and border becomes a little blurred as grass creeps over your once-clean outline. While many gardeners turn to metal or plastic edging ideas to keep things neat, the 3-inch rule is a simpler (and traditional) technique that uses nothing more than a sharp spade (like this from Lowe's) to create a clean, defined boundary between lawn and border.