As with most larger lawn projects, such as planting grass seed, it's best to aerate during or right before the time your grasses reach their peak time for natural growth. ... When aeration coincides with active growth, grasses recover quickly and fill in areas where aerator equipment exposes soil.

Do I need to aerate before seeding?

The most important step you can take before overseeding your lawn is aerating your soil. No matter what seed you use, they can't germinate in compacted soil devoid of water, nutrients, and sufficient air exchange. That's why it's crucial to aerate your lawn before starting the overseeding process.

Should I aerate before or after overseeding?

The verdict is that the two lawn care tasks should be paired together, as aeration innately complements overseeding efforts. The best place to start this conversation is with the importance of grass seed germination rate.