When to Overseed a Lawn in Washington
Most of Washington’s lawns get their best shot at overseeding in September, and the practical cutoff falls in early October west of the Cascades.
Gardening in Washington
Everything we have worked out for Washington: what to plant and when, which varieties finish in time, the pests that actually turn up here, and the jobs that pay off month by month. We also cover the rest of the property, from lawns and soil to home care and energy, because a garden rarely stops at the vegetable bed.
The numbers first, because everything else follows from them. Measured at the weather station in Seattle, the last spring freeze runs February 27 to March 18 and the first fall freeze runs November 13 to November 30, USDA zones 4a-9a, 2,353 growing degree days in the year.
That is enough for early varieties, tight for anything late. Garlic does well: 17.4 weeks below 40 °F, comfortably past the six it needs to form a proper head.
Elsewhere on the property in Washington: the pests that turn up here.
Figures from NOAA's 1991-2020 climate normals. A state is not one climate: elevation, a large lake or the coast can move these dates by two weeks either way, so check your own county with the extension service before you spend money.
First and Last Frost Dates in Washington
Western Washington’s last spring frost typically lands between February 27 and March 18, and the first fall frost arrives between November 13 and…
When to Pick Tomatoes in Washington, and Ripening the Rest
Full-size green tomatoes should come off the vine before the first fall frost hits, and in western Washington that window runs November 13 to November 30…
When to Harvest Garlic in Washington, and How to Cure It
Garlic tells you when it’s ready, not the calendar. Once the bottom leaves have browned and about five or six up top are still green, the bulb has…
When to Pick Apples in Washington, and How Long They Keep
The right day to pick an apple in Washington isn’t a date on a calendar. It’s a stage the fruit reaches: background skin color, seed color, and how…
Does Insulation Keep a Home in Washington Cool?
Yes, insulation helps keep a Washington home cooler, but the honest version of that answer depends on where in the state you live and how hot your…
Does a Wall in Washington Need a Vapor Barrier?
In Washington, a vapor retarder is required on the interior side of frame walls, and it applies to the whole state.
Heating With Pellets in Washington: What a Winter Takes
A winter in western Washington runs long before it runs brutal. Around Seattle, heating degree days land near 4,376 a year, a moderate load stretched…
Imported cabbageworm in Washington: When It Shows Up and What Stops It
Imported cabbageworm shows up in Washington gardens from mid-spring right through the first hard fall frost, with several overlapping generations feeding…
Cutworms in Washington: When It Shows Up and What Stops It
Cutworms show up in Washington gardens as soon as soil temperatures climb into the 50s, which in the mild, marine-influenced west side of the state…