If you are planning to use an area of decorative gravel in your landscape you probably are wondering how deep should landscaping rock be? This question arises in many scenarios. Perhaps you are putting a drip strip against a foundation. Alternatively, you may be xeriscaping an entire yard. How much stone do you need to buy? How deep should you spread it? In this article, we’ll explain best practices and provide some tips we use as landscape designers.
Questions To Ask For Landscaping Rock Depth
The first question to consider when calculating depth or landscape rock is how big the rock is. Rock is sold by the sieve or screen size. These sizes depend on the screen size used to separate out the rock. For example you might be able to buy the same type of rock in a 3”, 1 1/2”, 3/4”, or 3/8” size. If you are going to use the 3” stone, you’ll have larger air gaps between the stones. If you want a continuous layer where you don’t see the earth or geotextile fabric below the rock bed, you’ll need to use a thicker layer of the stones than you might if you are using 3/8” rock.
The next question to ask is how will the landscaping rock area be used? Will this be a pathway or is it a decorative border which will not be walked on? Will there be a stream running through the stone when it rains? Is there anything other than rainwater passing through the stone which you need to worry about?
How Deep Should Landscaping Rock Be?
One of our favorite ways to create an inexpensive walkway in a landscape is to use 3/8” sharp rock. We use sharp rock so the walkway is stable and doesn’t move around like sand as you walk. If you use tumbled or rounded stones, the walking experience is like walking in dry beach sand. However, even though the sharp stone is more stable, you still must consider what happens if someone drags their toe, turns without lifting their foot and so on. If you only put down a 2” thick layer, you will see bare spots within a few months of use and your walkway will look like an afterthought.
How Deep Should Landscaping Rock Be For Walkways?
So how deep should landscaping rock be for walkways? We always use 6” – 8” thick layer of landscaping rock for walkways. If you have any grade changes you may want to consider using some monolithic stone steps or steel edging steps to minimize stone consolidation. If you are using the gravel as a landscape rock in an area where nobody will be walking, we’d recommend a minimum of 4” thickness up to 3/4” stone. This may sound excessive, but if you’re spending the money to do this once, how about we only do it once?
If you’re using a larger size gravel, you want to at least triple the depth of the stone size. So for example, if you are using 3” stone, make your stone depth 9”. You might be able to get away with using less. If the stone is exceedingly expensive, you may want to try using less to see if you can make it work. However, in our experience it’s usually just cheaper to buy more material and place it once.
Pro Tip For Landscaping Rock Installation
Regardless of how deep your landscaping rock is, one of the keys to successful installation is to use geotextile fabric under the rock. This helps prevent the stone from pressing into the earth when the ground is soft. That will eventually cause consolidating into the soil. Another benefit of geotextile fabric is the prevention of weed growth. Regardless of how deep should landscaping rock be, you want to use a woven geotextile fabric so you can allow for water to pass through into the soil below. We’ve discussed similar challenges when explaining how to landscape over sand.
How Deep Should Landscaping Rock Be Summary
Now you know that the depth of landscaping rock depends on a few things. First, determine if you’ll be walking on the landscape rock. You should also factor in the rock size. If you will be walking, make it 6 to 8 inches deep. However, if you are not walking on it, you can use only 4 inches instead. It’s always a good idea to use geotextile fabric underneath your rock. You can rest assure this advice is sound, I work for a large residential landscape design firm and have installed landscaping rock countless times.