Silver Firs, Washington, sits in USDA hardiness zone 9a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Growers here do well with kale, potato, garlic, and western red cedar — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Silver Firs, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Silver Firs lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Silver Firs — soil, climate, flood, and parcel records. How we handle your address.
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Silver Firs — the short answer
Silver Firs, Washington: USDA zone 9a, about 208 days between hard freezes, across 4K acres of town.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 15
- Snohomish County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Nov 9
- Snohomish County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~208
- Snohomish County normal — NOAA 1991–2020, nearest to this town
- Town area
- 4K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Snohomish County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is Silver Firs's average, not your lot's — a low corner or a tree line moves it. Against Silver Firs's 208-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Silver Firs
Each reading below is measured for Silver Firs itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsSilver Firs runs about 208 days between hard freezes (read from Snohomish County, the closest normal to Silver Firs) — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredSilver Firs sits in USDA hardiness zone 9a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Silver Firs is in
Silver Firs sits in the Puget Lowland — EPA Level III, inside the wider Marine West Coast Forest. That is read at Silver Firs's own centroid, and it is not what its county reads: Snohomish County is mostly North Cascades. The wider page above you is answering a different question about different ground.
What Grows in Silver Firs
Plants matched to Silver Firs's USDA zones 9a, ordered by how much hardiness margin each has here — the ones with room to spare at both ends of this town's band lead. Each links to its full growing profile.
Is it too late to plant in Silver Firs?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 9 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
What's on the federal record near Silver Firs
Closest first, within ~10 miles of Silver Firs. Listing isn't leaking, and distance isn't exposure.
- FLEET MANAGEMENT DIVISIONUnderground Storage Tanks · 0.9 mi
- SAFEWAY FUEL 2645Underground Storage Tanks · 0.9 mi
- SAFEWAY 2645Brownfields · 1.0 mi
- 27N/05E-02Q01Nitrate · 1.2 mi
- PETCARE HOSPITAL AND WELLNESS CENTER MILL CREEKBrownfields · 1.2 mi
- CVS PHARMACY #11682Brownfields · 1.2 mi
- 27N/05E-10D02Nitrate · 1.4 mi
- MOLLGAARD FLORAL COMPANY INCUnderground Storage Tanks · 1.5 mi
- SEATTLE CITY LIGHT BOTHELL SUBSTATIONBrownfields · 1.5 mi
- 28N/05E-27K01 SU-019Nitrate · 1.5 mi
- SNOHOMISH REGIONAL LANDFILLBrownfields · 1.5 mi
- 28N/05E-33C01Nitrate · 1.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Silver Firs's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Silver Firs.
Total Sites
1,678
within ~10 miles of Silver Firs
Risk Level
Elevated
Highest-severity
4 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Silver Firs
Severity Distribution
within ~10 miles of Silver Firs
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Silver Firs
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Silver Firs average
Your land is one point inside Silver Firs
Everything above resolves to Silver Firs as a whole — one PHZM band, read across 4K acres, with hard-freeze dates borrowed from Snohomish County’s record because no 30-year normal resolves at this town’s own centroid. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at town scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the Silver Firs Average
Silver Firs Average
- ●USDA Zones 9a, averaged across Silver Firs
- ●One soil character for all of Silver Firs
- ●Frost dates read at Silver Firs's scale: Apr 15 to Nov 9
YOUR Parcel
- ✓Your exact zone, not Silver Firs's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Silver Firs
Pull a site-specific report for your exact address in Silver Firs, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Silver Firs averages can't show:
We read public map data around Silver Firs — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Silver Firs average
How we know this about Silver Firs
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Snohomish County’s record, because none resolves here; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Silver Firs
When does frost risk typically end in Silver Firs?
The last hard freeze (28°F) in Silver Firs typically lands around Apr 15, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about May 6.
When is the first frost in Silver Firs?
The first hard freeze (28°F) in Silver Firs typically arrives around Nov 9, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 26, so the watching starts about Oct 10 — about 208 days after the spring freeze cleared.
How long is the growing season in Silver Firs?
Measured between 28°F hard freezes, Silver Firs sees about 208 frost-free days — roughly Apr 15 through Nov 9, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 6 to Oct 26, about 173 days.
Is the soil safe to grow vegetables in Silver Firs?
The federal record around Silver Firs is a meaningful one — 1,678 documented sites, mostly Underground Storage Tanks entries (940), the nearest Underground Storage Tanks record about 0.9 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do I protect my plants from frost in Silver Firs?
From about Oct 10 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Nov 9 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Nov 9. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Silver Firs's scale — its 9a band and its 208-day season. Your yard writes its own version of Silver Firs's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Silver Firs’s own scale
4 of the readings below were taken at Silver Firs's own scale — the 4,387 acres it covers and 1,678 documented sites around it; 6 are borrowed from a wider read, named and linked below.
Measured here
- Silver Firs's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 1,678 documented contamination sites on the federal record near Silver Firs, the closest Underground Storage Tanks record about 0.9 miles out from the town centreFederal environmental registers
- Silver Firs's boundary and the 4,387 acres inside itUS Census TIGER/Line 2025
- Silver Firs sits in the Puget Lowland — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Silver Firs has no normal of its own, so its county's is the closest measured readfrom Snohomish County
- Soil character — no town-scale survey exists, so Silver Firs's 4,387 acres read through its county's SSURGO summaryfrom Snohomish County
- The candidate plant list — Washington's curated set, filtered to this zone band and re-ordered by how much margin each has herefrom Washington
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Snohomish County
- The growing challenges every Washington grower plans around — written at state scale, so they stay on the state guidefrom Washington
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Snohomish County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Silver Firs's 4,387 acreswhy one lot differs from the next →
- Which side of Silver Firs you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,387 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.9 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Silver Firs-wide figureread your own land →
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