In Beaverton, the best time to aerate and overseed is early fall, roughly September into early October. The soil is still warm, the rains are coming, and the weeds are slowing down.
Why fall beats spring here
Most lawns around Beaverton are cool-season grasses like perennial ryegrass and fine fescue. They grow strongest in cool, damp weather. Seed planted in early fall has months to root in before summer, while spring seed has to fight weeds and then survive a dry July.
Why aeration matters on clay
Much of the west side sits on heavy clay that packs down hard. Core aeration pulls out small plugs of soil so air, water and roots can get in. It also gives new seed a perfect little pocket to land in.
How to do it right
- Mow a little short first, then aerate in two directions.
- Overseed right away while the holes are open.
- Top-dress with a thin layer of compost if your soil is heavy.
- Keep it damp with light daily watering until the fall rains take over.
Skip it if…
If your lawn is mostly moss in a deep-shade spot, aeration alone won't fix it. That's a shade and drainage problem first. Our moss article covers what to do instead.
Want us to take a look?
We'll stop by for free and give you an honest plan, even if it's a job you can do yourself.
More: Moss in your lawn? Here's what actually fixes it · Native plants that thrive in Beaverton yards