Lawn Aeration Specialist. Aerating involves making holes in your lawn either by pushing a rod into it or by extracting a plug of soil. This allows a better flow of water, air, and vital nutrients to the plant roots, making it easier for them to grow. This does not, however, apply to soil types containing clay. It is best to aerate in late summer, then topdress and/or overseed. Signs that you need to aerate your lawn: The ground is hard and compacted. Thatch is building up. Water does not penetrate well. Weeds like prostrate knotweed and clover are present. more... See more text