When does pre-emergent application typically open in Woodinville, WA?

Pre-emergent application typically opens in April to May for Woodinville, WA, when 2-inch soil temperature reaches the 50–55°F threshold for several consecutive days. Apply earlier than that and the herbicide degrades before crabgrass germinates; apply later and weeds have already sprouted. This is informational guidance only, not a prescription. The label is the law. Consult your local Cooperative Extension office before applying any product.

What grass types grow best in Woodinville, WA?

Woodinville, WA is primarily a cool-season climate. Cool-season grasses (tall fescue, Kentucky bluegrass, perennial ryegrass, fine fescue) thrive when 2-inch soil sits in the 50–65°F range and slow down in midsummer heat. Picking a grass family that matches the climate is the single biggest lawn-care decision; transition-zone homeowners often maintain blends and accept that neither family will look perfect year-round. This is informational guidance only, not a prescription. The label is the law. Consult your local Cooperative Extension office before applying any product.

When is the first fall frost typically expected in Woodinville, WA?

In Woodinville, WA, the first fall frost typically arrives around October 22. Soil temperature continues to drop through October and November, which closes the fall fertilizer window for warm-season grasses and opens the dormant-seeding window for cool-season grasses. This is informational guidance only, not a prescription. The label is the law. Consult your local Cooperative Extension office before applying any product.

How often is this schedule updated?

Recommendations recompute every 6 hours from the latest reading at Darrington 21 NNE, about 62 miles from Woodinville. This is informational guidance only, not a prescription. The label is the law. Consult your local Cooperative Extension office before applying any product.

What soil temperature do cool-season grasses need to germinate?

Cool-season grasses like fescue, Kentucky bluegrass, and perennial ryegrass germinate best when 2-inch soil temperature sits in the 50–65°F range for several consecutive days. Above that, summer heat stresses young seedlings; below that, germination slows or stalls. The re-entry interval (REI) on any post-emergent products you apply during establishment is on the product label; respect it before letting pets or children back on treated areas. This is informational guidance only, not a prescription. The label is the law. Consult your local Cooperative Extension office before applying any product.

Where does the soil temperature data for Woodinville come from?

Soil temperature for Woodinville comes from Darrington 21 NNE, a station in the NOAA US Climate Reference Network (USCRN) located about 62 miles away. Daily readings at depths from 2 inches down to 40 inches feed the schedule's window-open and window-closing decisions. This is informational guidance only, not a prescription. The label is the law. Consult your local Cooperative Extension office before applying any product.

Woodinville Lawn Care Schedule: What To Do in July

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Weed

IN WINDOW

Prodiamine pre-emergent

Fall pre-emergent (Poa annua)

Annual bluegrass (Poa annua) germinates in cool, moist soil in early fall and overwinters as a dense, light-green pest in dormant warm-season turf. A fall pre-emergent stops the seed before it ever sprouts; once the plants are visible in winter, control gets much harder.

Read the full guide →

Shallow soil temperatures are in the action band at 66.6°F at the Darrington 21 NNE sensor, 62 miles from your location.

Window: Jul 29 to Oct 31. Window typically open for 2 to 3 weeks.

Why this, why now

[14] NC State Extension TurfFiles: Annual Bluegrass (2022)
[15] University of Georgia Extension: Annual Bluegrass Control in Residential Turfgrass (2024)

Safety details (REI, air-temp ceiling, pre-rain)

Keep pets and children off treated areas for 12 hours after application.

Air temperatures above 85°F can volatilize the product or stress the lawn. Wait for cooler conditions.

Apply at least 24 hours before forecast rain so the product binds before runoff.

Reseeding restriction: If you reseeded in the last 12 weeks, do NOT apply.

Cultivation

IN WINDOW

Fall overseeding (cool-season)

Spreading new seed in early fall fills thin spots while soil is still warm enough for fast germination but air is cool enough that the seedlings outpace summer weeds. Fall overseeding establishes a thicker stand than spring overseeding and avoids competition with crabgrass.

Shallow soil temperatures are in the action band at 66.6°F at the Darrington 21 NNE sensor, 62 miles from your location.

Window: Jul 29 to Sep 30. Window typically open for 2 to 3 weeks.

Why this, why now

[6] Penn State Extension: Lawn Establishment (2025)
[7] University of Maryland Extension: Starting a New Lawn (2026)

Cultivation

IN WINDOW

Fall core aeration (cool-season)

Fall aeration after a hot summer relieves compacted soil and gives roots access to air, water, and nutrients heading into the cool-season recovery window. Pairing aeration with overseeding drops the new seed into open holes for ideal soil contact.

Shallow soil temperatures are in the action band at 66.6°F at the Darrington 21 NNE sensor, 62 miles from your location.

Window: Jul 29 to Oct 31. Window typically open for 2 to 3 weeks.

Why this, why now

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About this schedule

Soil at 2 inches is currently 67°F. Fall core aeration (cool-season) is in window now. That is 1°F below the 30-year normal for this date. Data from NOAA US Climate Reference Network (USCRN), 62 miles away at Darrington 21 NNE.

Sources

Penn State Extension: Managing Thatch in Lawns (2025)
NC State Extension: Carolina Lawns: A Guide to Maintaining Quality Turf in the Landscape (2021)
University of Maryland Extension: Maintaining an Established Lawn (2026)
Penn State Extension: Liming Turfgrass Areas (2002)
Virginia Cooperative Extension (Virginia Tech): Fall Lawn Care (2025)
: Lawn Establishment (2025)

Lawn Care Schedule for Woodinville, WA

Right now in Woodinville

July

Fall pre-emergent (Poa annua)

Fall overseeding (cool-season)

Fall core aeration (cool-season)

August

September

October

November

December

About this schedule

Sources