The answer to 'which is better aeration or' is that aeration is generally better than overseeding for most lawns. Aeration involves punching small holes in the soil to allow air, water, and nutrients to better reach the roots of your grass. This can help improve the overall health and thickness of your lawn. In contrast, overseeding simply involves spreading grass seed over your existing lawn, which may not be as effective if the soil is compacted or the grass is already struggling.
The main benefits of aeration include improved water and nutrient absorption, reduced soil compaction, and better root growth. It's generally recommended to aerate your lawn annually, especially in high-traffic areas or clay-heavy soils. Overseeding can be a good complement to aeration, but it's not a substitute for the core aeration process.