September can be one of the best times to help a cool-season lawn recover from summer heat, foot traffic and dry spells. Cooler temperatures support new growth, while the soil is still warm enough for seed to establish. Timing varies by region and grass type, so check local guidance before getting started.

1. Inspect the lawn. Look for bare patches, compacted soil, weeds and areas where water tends to pool.

2. Aerate if needed. If the ground feels hard or rain runs off instead of soaking in, core aeration can loosen compacted soil and help air, water and nutrients reach the roots. 

3. Overseed thin areas. Choose a seed blend suited to your climate and sunlight conditions. Keep newly seeded soil consistently damp until the grass is established. 

4. Feed carefully. A fall fertilizer can support root growth, but follow product directions and avoid applying more than your lawn needs.

5. Keep mowing. Continue mowing while the grass is actively growing, removing no more than one-third of the blade height at a time. 

A focused fall reset can thicken the lawn, address summer damage and help it head into winter in better shape. Start early enough for new grass to establish before freezing weather arrives.