Cedar Hills, Oregon, sits in USDA hardiness zone 9a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Growers here do well with artichoke, fig, california poppy, and cabbage — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Cedar Hills, 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 Cedar Hills 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 Cedar Hills — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Cedar Hills — the short answer
Cedar Hills, Oregon: USDA zone 9a, about 274 days between hard freezes, across 1K acres of town.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 22
- Washington County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Nov 23
- Washington County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~274
- Washington County normal — NOAA 1991–2020, nearest to this town
- Town area
- 1K 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 Washington County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is Cedar Hills's average, not your lot's — a low corner or a tree line moves it. Against Cedar Hills's 274-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Cedar Hills
Each reading below is measured for Cedar Hills itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsCedar Hills runs about 274 days between hard freezes (read from Washington County, the closest normal to Cedar Hills) — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredCedar Hills 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 Cedar Hills is in
Cedar Hills sits in the Willamette Valley — EPA Level III, inside the wider Marine West Coast Forest. That is read at Cedar Hills's own centroid rather than borrowed from Washington County.
What Grows in Cedar Hills
Every plant below cleared Cedar Hills's own zone 9a and its 274-day season. Each card opens that plant's Oregon profile. How we score.
Is it too late to plant in Cedar Hills?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Jan 25; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 22 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 23 — long-season crops need about 90 days of runway, quick greens only 30. And with a calendar this mild, the honest answer is that planting barely stops — winter opens seasons colder regions never see.
Documented around Cedar Hills
Survey cells within 31 miles of Cedar Hills checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 537 miles off. What to watch for.
What's on the federal record near Cedar Hills
Closest first, within ~10 miles of Cedar Hills. Listing isn't leaking, and distance isn't exposure.
- RITE AID 5322Brownfields · 950 ft
- UNITED PACIFIC #5452Underground Storage Tanks · 1000 ft
- HARRIS ENTERPRISES INCUnderground Storage Tanks · 1100 ft
- UNOCAL 4810Underground Storage Tanks · 1900 ft
- OLD BUGATTI'S SITEUnderground Storage Tanks · 2100 ft
- OREILLY AUTO PARTS STORE NO 2513Brownfields · 2400 ft
- TEKTRONIX COMPONENT SOLUTIONSBrownfields · 0.5 mi
- TEKTRONIX COMPONENT SOLUTIONSToxics Release Inventory · 0.5 mi
- ALL TRANSMISSION SERVICE COUnderground Storage Tanks · 0.6 mi
- CEDAR HILLS BLVD CHEVRONUnderground Storage Tanks · 0.7 mi
- CEDAR PARK MIDDLE SCHOOLBrownfields · 0.7 mi
- NIKE IHM INCBrownfields · 0.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Cedar Hills'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 Cedar Hills.
Sources Checked
within ~10 miles of Cedar Hills
Severity Distribution
within ~10 miles of Cedar Hills
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Cedar Hills, Toxics Release Inventory runs higher than the national average — 262 sites within ~10 miles of Cedar Hills. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Cedar Hills
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 Cedar Hills average
Your land is one point inside Cedar Hills
Everything above resolves to Cedar Hills as a whole — one PHZM band, read across 1K acres, with hard-freeze dates borrowed from Washington 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 Cedar Hills Average
Cedar Hills Average
- ●USDA Zones 9a, averaged across Cedar Hills
- ●One soil character for all of Cedar Hills
- ●Frost dates read at Cedar Hills's scale: Feb 22 to Nov 23
YOUR Parcel
- ✓Your exact zone, not Cedar Hills's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Cedar Hills
Pull a site-specific report for your exact address in Cedar Hills, Oregon — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Cedar Hills averages can't show:
We read public map data around Cedar Hills — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Cedar Hills average
How we know this about Cedar Hills
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 Washington 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 Cedar Hills
When does frost risk typically end in Cedar Hills?
The last hard freeze (28°F) in Cedar Hills typically lands around Feb 22, 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 Mar 15.
When is the first frost in Cedar Hills?
The first hard freeze (28°F) in Cedar Hills typically arrives around Nov 23, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 9, so the watching starts about Oct 24 — about 274 days after the spring freeze cleared.
How long is the growing season in Cedar Hills?
Measured between 28°F hard freezes, Cedar Hills sees about 274 frost-free days — roughly Feb 22 through Nov 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 15 to Nov 9, about 239 days.
Is the soil safe to grow vegetables in Cedar Hills?
The federal record around Cedar Hills runs heavier than most — 3,800 documented sites, mostly Underground Storage Tanks entries (1,978), the nearest Brownfields record about 0.2 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do I protect my plants from frost in Cedar Hills?
From about Oct 24 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 23 (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 23. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Cedar Hills's scale — its 9a band and its 274-day season. Your yard writes its own version of Cedar Hills'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 Cedar Hills’s own scale
6 of the readings below were taken at Cedar Hills's own scale — the 1,200 acres it covers and 3,800 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Cedar Hills's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 3,800 documented contamination sites on the federal record near Cedar Hills, the closest Brownfields record about 0.2 miles out from the town centreFederal environmental registers
- Cedar Hills's boundary and the 1,200 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~274-day seasonGrowable Ground crop-matching engine
- The ecoregion at Cedar Hills's own centroid, the Willamette ValleyUS EPA Level III Ecoregions
- Lanternfly survey cells around Cedar Hills checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- The 28°F hard-freeze dates — Cedar Hills has no normal of its own, so its county's is the closest measured readfrom Washington County
- Soil character — no town-scale survey exists, so Cedar Hills's 1,200 acres read through its county's SSURGO summaryfrom Washington County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Washington County
- The growing challenges every Oregon grower plans around — written at state scale, so they stay on the state guidefrom Oregon
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Washington County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Cedar Hills's 1,200 acreswhy one lot differs from the next →
- Which side of Cedar Hills you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,200 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.2 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 Cedar Hills-wide figureread your own land →