2 months ago a new lawn was laid down in 'tiles' on a property in Belgium that I mow. It grew very fast at first, and was difficult to mow, as it had rained frequently. I had to stop and 'clean' mower every 5 minutes, the pile-up was so severe. Lately though, the growth has slowed, but the lawn is starting to look 'unhealthy' in many areas. It's brown and thin. I had noticed right after it was installed how the ground was very soft--like walking on a wedding cake in spots. Many of the 'tiles' at the outer corner areas are looking really bad. Possibly the installer didn't prepare earth underneath correctly? Not enough nutrients?
New Lawn Turning Brown and Thin
Certified GKH Gardening Expert
It is possible that the soil below the tiles is not draining well. The water from the rainfall would sit for a bit below the sod tiles and the grass' roots would start to rot. The more it happens, the more the grass would die.
Next time it rains, or the lawn is watered, try pulling up one of the tiles. If it comes up easily, then the grass has not grown into the soil below. Further check the roots that are there. If the roots feel mushy and put off a bad odor, they are rotting.