Hartline, Washington, sits in USDA hardiness zone 6b — a zone band wide enough that plant choice, not possibility, is the interesting question.
The conditions favor cabbage, blackberry, california poppy, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Hartline, 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 Hartline 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 Hartline — soil, climate, flood, and parcel records. How we handle your address.
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Hartline — the short answer
Hartline, Washington: USDA zone 6b, about 176 days between hard freezes, across 214 acres of town.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 19
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~176
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 214 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 6b is Hartline's average, not your lot's — a low corner or a tree line moves it. Against Hartline's 176-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Hartline
Each reading below is measured for Hartline itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredHartline runs about 176 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredHartline sits in USDA hardiness zone 6b.
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 Hartline is in
Hartline sits in the Columbia Plateau — EPA Level III, inside the wider North American Deserts. That is read at Hartline's own centroid rather than borrowed from Grant County.
What Grows in Hartline
Every plant below cleared Hartline's own zone 6b and its 176-day season. Each card opens that plant's Washington profile. How we score.
Is it too late to plant in Hartline?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 29; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 26 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 19 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Hartline
Closest first, within ~10 miles of Hartline. Listing isn't leaking, and distance isn't exposure.
- GRANT COUNTY FIRE DISTRICT 6Underground Storage Tanks · 300 ft
- GRANT COUNTY PUBLIC WORKS SHOPUnderground Storage Tanks · 650 ft
- COULEE HARTLINE JR HI SCHOOLUnderground Storage Tanks · 1600 ft
- KELLEY BROSUnderground Storage Tanks · 4.4 mi
- SENKLER FARMS INCUnderground Storage Tanks · 4.4 mi
- WALESBY FARMS INCUnderground Storage Tanks · 4.4 mi
- US BUREAU OF RECLAMATIONUnderground Storage Tanks · 7.3 mi
- BOB ZIMMERMANUnderground Storage Tanks · 7.7 mi
- HARRINGTON CITY OFUnderground Storage Tanks · 7.7 mi
- ALMIRA FARMERS WAREHOUSE COUnderground Storage Tanks · 7.7 mi
- 26N/31E-32B01 MW-SU-066Nitrate · 7.8 mi
- ELROY C CRUMUnderground Storage Tanks · 7.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Hartline'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 Hartline.
Total Sites
29
within ~10 miles of Hartline
Risk Level
Low
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Hartline
Severity Distribution
within ~10 miles of Hartline
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Hartline, Underground Storage Tanks runs higher than the national average — 23 sites within ~10 miles of Hartline. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Hartline
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 Hartline average
Your land is one point inside Hartline
Everything above resolves to Hartline as a whole — one PHZM band and one 28°F frost record, read across 214 acres. 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 Hartline Average
Hartline Average
- ●USDA Zones 6b, averaged across Hartline
- ●One soil character for all of Hartline
- ●Frost dates read at Hartline's scale: Apr 26 to Oct 19
YOUR Parcel
- ✓Your exact zone, not Hartline's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Hartline
Pull a site-specific report for your exact address in Hartline, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Hartline averages can't show:
We read public map data around Hartline — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Hartline average
How we know this about Hartline
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 Hartline’s own record; 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 Hartline
When does frost risk typically end in Hartline?
The last hard freeze (28°F) in Hartline typically lands around Apr 26, 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 17.
When is the first frost in Hartline?
The first hard freeze (28°F) in Hartline typically arrives around Oct 19, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 5, so the watching starts about Sep 19 — about 176 days after the spring freeze cleared.
How long is the growing season in Hartline?
Measured between 28°F hard freezes, Hartline sees about 176 frost-free days — roughly Apr 26 through Oct 19, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 17 to Oct 5, about 141 days.
Is the soil safe to grow vegetables in Hartline?
The federal record around Hartline is light — 29 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (23), the nearest Underground Storage Tanks record under a tenth of a mile out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Hartline?
From about Sep 19 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 Oct 19 (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 Oct 19. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Hartline's scale — its 6b band and its 176-day season. Your yard writes its own version of Hartline'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 Hartline’s own scale
6 of the readings below were taken at Hartline's own scale — its own ~176-day season between 28°F freezes, the 214 acres it covers and 29 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Hartline's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Hartline's own 28°F hard-freeze dates, about Apr 26 and Oct 19 and the ~176-day span between themNOAA 1991–2020 Climate Normals
- 29 documented contamination sites on the federal record near Hartline, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Hartline's boundary and the 214 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~176-day seasonGrowable Ground crop-matching engine
- The ecoregion at Hartline's own centroid, the Columbia PlateauUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Hartline's 214 acres read through its county's SSURGO summaryfrom Grant County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Grant 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 Grant County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Hartline's 214 acreswhy one lot differs from the next →
- Which side of Hartline you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 214 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile 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 Hartline-wide figureread your own land →
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