We have some nice 6" long roots on the putting green at the practice facility. New greens with new sand that has ample pore space always produces the best rooting. As the greens age and organic matter fills those pores, rooting is negatively impacted. This is why aeration is so important! The goal is to remove organic matter and back fill the holes with new sand that will stimulate rooting which ultimately leads to healthy turf. Without good roots, you won't have good turf. What is happening above ground is a direct reflection of what is occurring below ground.