Wood and Stone
Laying railroad ties and landscape timbers or stone edges along your garden or lawn can be an effective way to prevent weed growth, but proper installation is critical to success. If you place the edging on the soil surface, weeds can grow beneath and work their way through. Instead, bury the first layer of wood or stone about 6 inches deep into the soil and build the edge so the top is at least 3 inches above the soil. This prevents weeds from establishing beneath the edging and from creeping over it.
Wood mulches or gravel smother weeds so they don’t have a chance to germinate, but you must lay them over weed-free soils to be effective. You can also line the soil with landscape fabric or black plastic, both of which will smother existing weed seeds and roots, and lay your mulch material over top. Add new mulch to the edge as needed to ensure the edge is a minimum of 4 to 6 inches deep, and make sure it is well away from woody-stemmed plants to avoid rotting.
Root barriers are typically made of hard materials, such as paving slabs, and they provide a wide edge that you can also use as a walkway. Not only do these edges prevent weeds from encroaching into your garden, but also they can restrict invasive plants and are easy to install. While root barriers prevent weeds from growing beneath, they are usually level with the surface of the soil, so regular trimming of your lawn and clearing the barrier of debris is necessary to prevent weed seeds from blowing over the edge and into your garden.
Cement or Brick
An edge made of cement or brick lasts for years and prevents weeds from growing under or over the edge and into your garden. However, this type of weedless edging can be costly. A cement edge isn’t as warm or natural as other materials, but it provides a permanent edge that isn’t easily damaged. Mortar brick edging in place to prevent the bricks from toppling over.
No Cost Edge
Digging a simple 6-inch-deep trench around the edge of your garden is an inexpensive way to prevent weeds. Dig the trench so the walls angle toward your garden to prevent the sides from crumbling inward and to prevent grass roots from spreading into the garden. One drawback of this type of weed-free edging is that you have to keep it free of debris, such as leaves, and re-dig it about two to three times each year.