If you’re planning to install artificial grass without doing any excavation first, please stop now and hire a professional contractor. In all seriousness, if you lay artificial grass without excavating your lawn first, you’ll end up with a comically uneven lawn.
The solution to this problem is simple as long as you haven’t started laying grass yet.
In normal draining areas, you need to excavate to a minimum of three inches below the height of your lawn. If you’re laying artificial grass in an area with poor drainage, the excavation depth should be increased to four inches.
Remember that the excavation process should include weeds as well as grass.