Gravel can be the ideal solution for mulching paths, patios, and even some types of garden beds in the landscape. A weed-free gravel area requires good installation practices and some ongoing maintenance.
1. Choose Dense Gravel
The type of gravel you choose can impact how easily weeds can invade the site. The ideal gravel is either small and dense, like pea gravel, or large and dense with angular sides so it fits together tightly with few spaces between rocks. Avoid large and lightweight or rounded gravel if you are trying to avoid weeds, since these don't fit together tightly and there is plenty of air space between the rocks for weeds to grow.
2. Edge and Line
The site should ideally be prepped before the gravel is delivered. Dig down deep enough so you can have a gravel depth that is sufficient to suppress weed growth from below. Then, line the bed with heavy-duty landscaping fabric to create a root barrier to any weed seeds that may try to germinate in the soil. Installing edging around the area to be graveled will prevent weed invasion from the sides and hold the gravel in place.
3. Add Some Sand
You don't have to fill in the entire site with gravel. First, create a barrier between gravel and the lined bottom with an inch or two of sand. Sand protects the landscape fabric from damage and further helps suppress weeds from below. It also helps anchor the gravel in place. Polymetric sand, which is also sold as patio sand, locks together once dampened to create an optimum barrier.
4. Lay It Deep
The depth of the gravel should be 3 to 5 inches. At this depth, it is hard for any weed seeds that blow in to grow roots fast enough to penetrate through the sand and landscape fabric before the plants die from a lack of nutrients and water. Installing the gravel deep also stops ugly bare spots from developing. Make sure to measure the volume (depth, length, and width) of the area you are installing the gravel so you can order enough from the delivery service.
5. Maintain It Regularly
Even with the right gravel and proper installation, weeds may still invade if dead leaves and other organic matter collect on top of the rocks. The organic matter breaks down and creates a soil layer in the gravel over time in which weeds can root. The solution is simple — either rake the gravel or use a leaf blower to remove the debris before it can decompose.
Contact a gravel delivery service to learn about the gravel options available in your area.