Colfax, Washington, sits in USDA hardiness zone 7a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Growers here do well with cabbage, pawpaw, california poppy, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Colfax, 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 Colfax 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 Colfax — soil, climate, flood, and parcel records. How we handle your address.
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Colfax — the short answer
Colfax, Washington: USDA zone 7a, about 191 days between hard freezes, across 2K acres of city.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 11
- 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
- ~191
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 2K 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 7a is Colfax's average, not your lot's — a low corner or a tree line moves it. Against Colfax's 191-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Colfax
Each reading below is measured for Colfax itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredColfax runs about 191 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
MeasuredColfax sits in USDA hardiness zone 7a.
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 Colfax is in
Colfax sits in the Columbia Plateau — EPA Level III, inside the wider North American Deserts. That is read at Colfax's own centroid rather than borrowed from Whitman County.
What Grows in Colfax
Every plant below cleared Colfax's own zone 7a and its 191-day season. Each card opens that plant's Washington profile. How we score.
Is it too late to plant in Colfax?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 11 (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. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
What's on the federal record near Colfax
Closest first, within ~10 miles of Colfax. Listing isn't leaking, and distance isn't exposure.
- 17N/44E-32A02 SU08Nitrate · 1.0 mi
- LARRY COCHRANUnderground Storage Tanks · 1.5 mi
- 17N/43E-24P01 LE14Nitrate · 2.3 mi
- 17N/43E-24C02 SU07Nitrate · 2.8 mi
- COLFAX MAINTENANCE SITEUnderground Storage Tanks · 2.9 mi
- WA DOT MAINTENANCE FACILITYUnderground Storage Tanks · 3.5 mi
- COLFAX SCHOOL DISTRICT 300Underground Storage Tanks · 3.5 mi
- BILL DURHAMUnderground Storage Tanks · 3.5 mi
- ROGERS SEED CO COLFAXBrownfields · 3.5 mi
- BUSCH DIST INCUnderground Storage Tanks · 3.6 mi
- WHITMAN COUNTY ROAD DEPTUnderground Storage Tanks · 3.6 mi
- CORNER CHEVRONUnderground Storage Tanks · 3.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Colfax'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 Colfax.
Sources Checked
within ~10 miles of Colfax
Severity Distribution
within ~10 miles of Colfax
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Colfax, Underground Storage Tanks runs higher than the national average — 88 sites within ~10 miles of Colfax. 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 Colfax
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 Colfax average
Your land is one point inside Colfax
Everything above resolves to Colfax as a whole — one PHZM band and one 28°F frost record, read across 2K 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 city 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 Colfax Average
Colfax Average
- ●USDA Zones 7a, averaged across Colfax
- ●One soil character for all of Colfax
- ●Frost dates read at Colfax's scale: Apr 11 to Oct 19
YOUR Parcel
- ✓Your exact zone, not Colfax's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Colfax
Pull a site-specific report for your exact address in Colfax, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Colfax averages can't show:
We read public map data around Colfax — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Colfax average
How we know this about Colfax
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Colfax’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 city grain anywhere on this page — there is no city-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 Colfax
When does frost risk typically end in Colfax?
The last hard freeze (28°F) in Colfax typically lands around Apr 11, 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 2.
When is the first frost in Colfax?
The first hard freeze (28°F) in Colfax 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 191 days after the spring freeze cleared.
How long is the growing season in Colfax?
Measured between 28°F hard freezes, Colfax sees about 191 frost-free days — roughly Apr 11 through Oct 19, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 2 to Oct 5, about 156 days.
Is the soil safe to grow vegetables in Colfax?
The federal record around Colfax shows 124 documented sites, mostly Underground Storage Tanks entries (88), the nearest Nitrate record about 1.0 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Colfax?
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 Colfax's scale — its 7a band and its 191-day season. Your yard writes its own version of Colfax'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 Colfax’s own scale
6 of the readings below were taken at Colfax's own scale — its own ~191-day season between 28°F freezes, the 2,421 acres it covers and 124 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Colfax's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Colfax's own 28°F hard-freeze dates, about Apr 11 and Oct 19 and the ~191-day span between themNOAA 1991–2020 Climate Normals
- 124 documented contamination sites on the federal record near Colfax, the closest Nitrate record about 1.0 miles out from the town centreFederal environmental registers
- Colfax's boundary and the 2,421 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~191-day seasonGrowable Ground crop-matching engine
- The ecoregion at Colfax's own centroid, the Columbia PlateauUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Colfax's 2,421 acres read through its county's SSURGO summaryfrom Whitman County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Whitman 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 Whitman County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Colfax's 2,421 acreswhy one lot differs from the next →
- Which side of Colfax you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,421 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 1.0 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 Colfax-wide figureread your own land →
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