Lawn aeration is necessary when your soil becomes compacted or when thatch builds up to the point where water, air, and nutrients can't reach grass roots effectively. Here's when to do it:

Signs your lawn needs aeration:

Water puddles or runs off instead of soaking in

The lawn feels spongy or has more than ½ inch of thatch

Soil is hard and difficult to push a screwdriver into

Grass looks thin or stressed despite regular watering and fertilizing

Heavy foot traffic, kids, or pets use the lawn frequently

Timing by grass type:

Cool-season grasses (fescue, bluegrass, ryegrass) — aerate in early fall or spring

Warm-season grasses (bermuda, zoysia, St. Augustine) — aerate in late spring to early summer

Situational triggers:

After a new home construction (soil is often heavily compacted from equipment)

If your lawn was established by sod (which can develop a layered soil problem)

Clay-heavy soils generally need aeration annually

Sandy soils typically only need it every 2–3 years