Owner-operated since 2004 • Licensed & insured • Not a franchise • Seattle-specific methods

Summary: You’ve just invested in your lawn. This page shows exactly how to water, mow, and protect new seed after Dethatching (Power Raking), Core Aeration, and Overseeding—so you get faster fill-in, fewer bare spots, and a thicker lawn.

At-a-Glance Schedule

Day 0–3 (right after service)

  • Core Aeration: Leave the cores; they break down and top-dress the soil. (They’ll disappear in ~1–3 weeks with rain/irrigation.)
  • Overseeding: Keep the lawn evenly moist—not soggy. Aim for 2–3 brief waterings per day if there’s no rain.
  • Traffic: Keep people, pets, and mowers off newly seeded areas.

Week 1

  • Watering: Continue light/frequent irrigation for overseeded areas. If it rains, skip a cycle.
  • Weed control: No herbicides on new seed.
  • Mowing: If not overseeded, you may mow once grass is – 3″–3.5″—use a sharp blade.

Weeks 2–3

  • Watering: Continue light/frequent irrigation for overseeded areas. If it rains, skip a cycle.
  • Mowing (overseeded): First mow when most seedlings reach 4 in; cut to 3–3.25 in. Go slow; bag clippings if heavy.
  • Traffic: Limit heavy turns, furniture, dog zoomies.

Weeks 4–6

  • Fertilizer: If we applied Starter Fertilizer, plan the next feeding 4–6 weeks later (ask about our Organic 5-4-5 upgrade).
  • Watering: Shift to deep, infrequent (3–4×/week total including rainfall). Seattle fall often supplies part of this.
  • Weed control: After 4–6 weeks, you may spot-treat if needed (avoid broadleaf herbicides on brand-new seedlings ).

Bookmark this page. Seattle weather can swing; use the troubleshooting section below to adjust.

Watering Details (Seattle-smart)

Goals: Keep seed moist (not floating), prevent runoff, once grass starts to grow start transitioning to deeper and less frequent watering.

Overseeding water plan

  • Days 0–21: 2–3 light cycles/day. Example: 8–12 minutes on fixed sprays; 15–20 minutes on rotors. Adjust for shade/sun and soil.
  • Days 21–28: 1 light cycle/day or every other day, then begin deeper cycles (20–30 minutes rotors) every 2–3 days.
  • After 4 weeks: Deep/infrequent schedule (2–3 total water days/week including rainfall).

Core Aeration without overseeding

  • Water normally. If soil dries hard, add one deep cycle to help cores melt and microbes mineralize.

Rain & runoff

  • If puddling occurs, split one long cycle into two shorter cycles an hour apart. In heavy rain, turn irrigation off until the surface firms up.

Mowing & Traffic

  • First mow (overseeded): When most new grass reaches 4 in; cut to 3–3.25 in. Keep blades sharp; slower wheel speed; gentle turns.
  • Frequency: Weekly is typical; never remove more than 1/3 of the blade.
  • Traffic limits: Avoid sports, dog zoomies, and heavy furniture for 2–3 weeks (longer on wet soils). Use boards under ladders/wheelbarrows.

What to Expect (totally normal)

  • After Dethatching: The lawn will look “ruffled” and thinner for a short time—this is normal. Any remaining thatch remnants will settle after a few mows.
  • After Aeration: Soil cores on the surface, temporary lumpiness, and faster drying on sunny/windy days. Cores break down on their own.
  • After Overseeding: Uneven, patchy sprout at first (7–21 days depending on temps). Shadier, cooler spots sprout slower.

Troubleshooting & Quick Fixes

  • Bare spot won’t fill: Lightly scratch the area with a hand rake, re-seed, and press seed into contact (your shoe or a roller). Keep moist.
  • Puddles/runoff: Split watering into multiple shorter cycles. Consider a wetting agent on hydrophobic soils.
  • Weeds popping: Hand-pull during first 4–6 weeks. Post-emergent herbicides only after the new lawn has matured.

Frequently Asked Questions

How soon can I mow after overseeding?
When most seedlings reach 3 inches. Mow high (3–3.25 inches) with a sharp blade; go slow and avoid tight turns.

Can I use Weed-and-Feed on new seed?
Avoid combined weed-and-feed or broadleaf herbicides until new lawn has matured.

Should I bag or mulch clippings?
During the first 1–2 mows after overseeding, bag the clippings.

How long should we stay off the lawn?
Keep people and pets off for 21-28 days in overseeded areas; limit heavy use for 3–4 weeks.

What about the aeration cores—should I rake them up?
Leave them. They crumble back into the lawn, improving soil and thatch breakdown.

When will I see results?
You’ll see early filling in 3–4 weeks; thicker, more resilient lawn in 4–5 weeks with proper watering and mowing.