Norway Spruce Screen Planting Distance
A noisy gas compressor station was just built next door to our farm. We've talked them into planting a Norway Spruce screen in front of their actual building. And we'll also be planting additional NS trees ourselves along our mutual property line.
They are talking about planting two rows of 6' tall trees in front of their building. What planting distance should we suggest to them to get a relatively quick eventual solid hedge? I doubt they would be willing to plant at 6' centers and then thin later. These will probably be left to grow as is. However, we are in our 50s, so don't want to wait forever for the trees to fill in. Thanks.