Nicole wrote:
core aeration. the spikes just compact the ground.
i always rent an aerator since it's not something i do a lot
nicole

I agree. One of the goals of aeration is to reduce compaction. When
you take a core out, you actually remove a significant plug of soil,
which reduces compaction. The spike type will create a small hole, but
does it by pushing the soil to the sides which just increases
compaction in the adjacent area. Plus, another benefit of aeration is
supposed to be bringing some of the soil up to the surface, so that it
creates a favorable environment to break down thatch. You get that
with a core aerator, but not spike.