Aeration- What about Thatch?     
Thatch and compaction are often a big threat to a homeowner's lawn. Fortunately, there's an easy solution - core aeration.

Thatch is composed of layers of living and decaying stems and roots between the green vegetation and the soil. Some thatch is normal - even healthy since it retains moisture, reduces compaction and increases tolerance to wear. Most lawns are subject to thatch accumulation. Excess thatch can be the result of neglect. A lack of microbial activity allows thatch to accumulate. Microbes need air and moisture to break down thatch.

Thatch can lead to serious problems. Thatch impedes water and fertilizer from reaching the roots. Thatch can suffocate your lawn by depriving the roots of oxygen and cause the grass roots to stay closer to the surface. Thatch is also the breeding ground for most of the diseases and damaging insects. Too much thatch can also reduce pesticide effectiveness.

Thatch will almost always get worse with time, not better You have two choices if you have excess thatch:

1.You can dethatch your lawn with a vertical cutter. This will remove much thatch but this process is invasive and will also uproot the healthy grass plants.
2.The alternative - we recommend is core aeration because not only does it work better, it offers the least amount of disturbance to the healthy plants.