St. Helens, Oregon, sits in USDA hardiness zones 4a-5b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Reliable performers under these conditions include hazelnut, blueberry, kale, and hop; what your own ground favors still comes down to its soil, sun, and drainage.
Even in St. Helens, 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 St. Helens lot. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Quick Facts
USDA Zones
4a-5b
Last Frost (state avg.)
Mar 1 - Jun 15
First Frost (state avg.)
Sep 1 - Nov 15
City Area
3K acres
Hardiness Zone Range
Growing Season
Zone maps are averages across St. Helens. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil varies lot by lot — soil types explained.
What Grows in St. Helens
Plants matched to St. Helens's USDA zones 4a-5b — each links to its full growing profile.
Growing Challenges in Oregon
What an experienced grower plans around here — each one has a move.
West side: excessive rain and overcast skies reduce sun for warm-season crops
Map your sun honestly — a south-facing bed against a light wall recovers a surprising amount of the light the clouds take.
East side: arid conditions (8-15 inches rainfall) require irrigation
East of the Cascades, drip irrigation is infrastructure, not an accessory — plan it before the first planting.
Slug pressure is extreme in western Oregon
Evening patrols, iron-phosphate baits, and dry mulch edges knock slugs back — your extension guide covers the full toolkit.
Mountain areas have very short seasons (60-90 frost-free days)
At 60-90 frost-free days, season extension is the difference between a garden and a gamble — a high tunnel changes the math.
For cultivar selection, pest pressure, and planting-time guidance specific to Oregon, the OSU Extension Service is the authoritative local source.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Sources Checked
within ~10 miles of St. Helens
Severity Distribution
within ~10 miles of St. Helens
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around St. Helens, two things run higher than the national average — Superfund (7 sites) and PFAS (4 sites). That's not a problem with your land — it's information about it.
Superfund: Superfund sites represent the most severe contamination in the federal system.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in St. Helens
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Your Specific Parcel Matters
St. Helens Average
- ●USDA Zones 4a-5b
- ●Generic soil type for the area
- ●State-average frost dates
YOUR Parcel
- ✓Your exact hardiness zone
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in St. Helens
Pull a site-specific report for your exact address in St. Helens, Oregon — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Key Growing Facts for St. Helens, Oregon
- USDA Hardiness Zones: 4a-5b (USDA PHZM 2023)
- Last Spring Frost (state avg.): Mar 1 - Jun 15 (NOAA 30-Year Climate Normals)
- First Fall Frost (state avg.): Sep 1 - Nov 15 (NOAA 30-Year Climate Normals)
- Land Area: 3K acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. Boundaries: US Census TIGER/Line 2025.
Frequently Asked Questions
What hardiness zone is St. Helens, Oregon?
St. Helens sits in USDA hardiness zones 4a-5b, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
When does frost risk typically end in St. Helens?
St. Helens follows Oregon's statewide frost window: last spring frost around Mar 1 - Jun 15 and first fall frost around Sep 1 - Nov 15, per NOAA 30-year climate normals (1991–2020). Frost dates shift with elevation and local microclimate, so watch your own site's cold pockets.
What vegetables grow in St. Helens?
St. Helens's zones 4a-5b support a wide range — strong performers include Hazelnut, Blueberry, Kale, Hop, and Douglas Fir. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Which hardiness zone is St. Helens, really?
Officially, St. Helens sits in USDA zones 4a-5b (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,112 plants against what's actually there.
Is the soil safe to grow vegetables in St. Helens?
The federal record around St. Helens runs heavier than most — 275 documented sites — 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 St. Helens?
As the season closes around Oregon's first fall frost near Sep 1 - Nov 15 (NOAA 30-year climate normals (1991–2020)), a few moves buy time: cover tender plants with floating row cover or an old sheet on still, clear nights, water the soil the afternoon before a freeze so it holds warmth overnight, and harvest frost-tender crops like tomatoes, peppers, and basil before the first hard night. Hardy greens and root crops shrug off light frost and often sweeten after it, so leave them in.
Everything on this page is a St. Helens average. Your yard writes its own version — we read soil, sun, drainage, and frost at your exact address. Try it for 14 days — no card required.
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