Lawn Renovation & Overseeding in Seattle, WA

Lawn renovation and overseeding in Seattle help lawns that are thin, patchy or losing ground to moss, but still have enough healthy grass that tearing everything out would be a waste. We loosen the surface, aerate where soil is compacted, and seed into the existing turf so new grass fills the gaps. For bare patches larger than a few square feet, we spray hydroseed directly onto the repaired soil. Lawn repair costs far less than a full new lawn installation and causes much less disruption.

Why Seattle lawns thin out

The city's climate is hard on turf at both ends of the year. Long, cloudy, wet stretches from fall through spring favor moss, especially under trees and on the north side of houses. Then a nearly dry summer browns out lawns that are not watered, and some grass never fully comes back. Add shade from big conifers, compacted soil from foot traffic and the shallow gravelly soils common in western Washington, and many lawns slowly lose density year after year.

When to overseed

Early fall is our first choice. The summer's heat is gone, the soil is still warm, and returning rain keeps new seed moist with little effort on your part. Spring overseeding also works, but the young grass has a short time to toughen up before summer drought, so it needs more watering in July and August. We generally do not overseed in midsummer unless the lawn is irrigated.

Moss is a symptom

Killing moss without fixing the conditions that let it in only buys a season. We look at the reasons: too much shade, wet or compacted soil, or turf that is simply too thin to compete. Where shade is the problem, we lean on shade-adapted tall fescue and fine fescues in the seed mix. Where it is compaction, core aeration before overseeding opens the surface. Where it is drainage, regrading may be the real fix.

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Renovation versus a new lawn

If at least half the lawn is decent grass and the soil drains reasonably well, renovation usually makes sense. If the yard is mostly weeds, moss or bare ground, or if the soil is badly compacted or uneven, it is often cheaper in the long run to regrade, add topsoil and hydroseed the whole area. We will tell you which we think fits after looking at it.

Feeding a renovated lawn

Overseeding works better when the existing lawn is fed at the right times. Seattle Public Utilities' lawn guidance suggests slow-release or natural organic fertilizer, applied in mid to late May and again in early September, with the fall feeding the most important if you only do one. WSU recommends 3 to 4 pounds of nitrogen per 1,000 square feet a year for home lawns, and leaving clippings on the lawn can supply about a quarter of that. Avoid heavy feeding in early spring, which pushes fast top growth.

Lime and soil testing

Soils west of the Cascades are often low in calcium, according to the same guidance, and lime is applied in spring or fall when a soil test shows a deficiency or a pH under 5. We recommend a soil test before a major renovation so lime and fertilizer go on based on numbers, not guesses.

Mowing habits that keep a lawn thick

Mowing high and often, and leaving the clippings, helps a renovated lawn shade out weeds and moss and holds moisture in the soil through the dry months. Scalping a lawn short in summer is one of the fastest ways to undo an overseeding.

Patch repair after projects

Not every repair is about moss. Dog runs, trenches from a side-sewer or irrigation repair, ruts from a delivery truck and bare spots under a removed play structure all leave a lawn with clear gaps. We loosen the soil, level it with topsoil where it has settled, and seed or hydroseed the patch so it blends in with the lawn around it. Matching the new seed to the existing grass type helps the repair disappear in a season.

Lawns that never recovered from summer

After a dry summer, many lawns that were not watered come back on their own once the rains return. Some do not, especially thin turf on shallow, gravelly soil. Early fall is when we can tell the difference and overseed the areas that stayed brown.

If you are unsure whether your lawn needs repair or replacement, send a few photos and we will tell you what we see before we visit.

What a renovation visit includes

• Raking out moss and thatch where it has built up
• Core aeration in compacted areas
• Overseeding with a cool-season blend matched to sun and shade
• Topdressing or topsoil in low and bare spots
• Spot hydroseeding for larger bare patches
• Written care notes for watering and the first mow