Colfax, California, sits in USDA hardiness zone 9a — 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 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 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.
No card required · your full report in seconds
Colfax — the short answer
Colfax, California: USDA zone 9a, about 290 days between hard freezes, across 900 acres of city.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 23
- Placer County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 10
- Placer County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~290
- Placer County normal — NOAA 1991–2020, nearest to this town
- City area
- 900 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 Placer County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is Colfax's average, not your lot's — a low corner or a tree line moves it. Against Colfax's 290-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
From county recordsColfax runs about 290 days between hard freezes (read from Placer County, the closest normal to Colfax) — 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
MeasuredColfax 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 Colfax is in
Colfax sits in the Sierra Nevada — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Colfax's own centroid rather than borrowed from Placer County.
What Grows in Colfax
Every plant below cleared Colfax's own zone 9a and its 290-day season. Each card opens that plant's California 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 Jan 26; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 10 — 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.
What's on the federal record near Colfax
Closest first, within ~10 miles of Colfax. Listing isn't leaking, and distance isn't exposure.
- PDF PRINT COMMUNICATIONSBrownfields · 500 ft
- 7-ELEVEN 42033Brownfields · 1000 ft
- DOLLAR GENERAL #16185Brownfields · 1000 ft
- UNION PACIFIC RAILROADBrownfields · 1000 ft
- ARCO AMPMBrownfields · 1000 ft
- SIERRA ENERGY #15Underground Storage Tanks · 1000 ft
- SANTA FE PACIFIC PIPELINE CISCO GROVE STATIONBrownfields · 1000 ft
- HANSEN BROS ENTERPRISESBrownfields · 1100 ft
- SIERRA SUPER STOP #15Brownfields · 1100 ft
- HICKEY'S AUTOBODYBrownfields · 1300 ft
- ALL PHASE AUTOBrownfields · 1300 ft
- WRIGHTS ALL PHASE AUTOBrownfields · 1400 ft
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, two things run higher than the national average within ~10 miles of Colfax — Mining (187 sites) and PFAS (5 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
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, read across 900 acres, with hard-freeze dates borrowed from Placer County’s record because no 30-year normal resolves at this city’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 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 9a, averaged across Colfax
- ●One soil character for all of Colfax
- ●Frost dates read at Colfax's scale: Feb 23 to Dec 10
YOUR Parcel
- ✓Your exact zone, not Colfax's 9a
- ✓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, California — 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 Placer 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 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 Feb 23, 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 16.
When is the first frost in Colfax?
The first hard freeze (28°F) in Colfax typically arrives around Dec 10, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 26, so the watching starts about Nov 10 — about 290 days after the spring freeze cleared.
How long is the growing season in Colfax?
Measured between 28°F hard freezes, Colfax sees about 290 frost-free days — roughly Feb 23 through Dec 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 16 to Nov 26, about 255 days.
Is the soil safe to grow vegetables in Colfax?
The federal record around Colfax runs heavier than most — 497 documented sites, mostly Brownfields entries (245), the nearest Brownfields record under a tenth of a mile 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 Colfax?
From about Nov 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 Dec 10 (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 Dec 10. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Colfax's scale — its 9a band and its 290-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
5 of the readings below were taken at Colfax's own scale — the 900 acres it covers and 497 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Colfax's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 497 documented contamination sites on the federal record near Colfax, the closest Brownfields record under a tenth of a mile out from the town centreFederal environmental registers
- Colfax's boundary and the 900 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~290-day seasonGrowable Ground crop-matching engine
- The ecoregion at Colfax's own centroid, the Sierra NevadaUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Colfax has no normal of its own, so its county's is the closest measured readfrom Placer County
- Soil character — no town-scale survey exists, so Colfax's 900 acres read through its county's SSURGO summaryfrom Placer County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Placer County
- The growing challenges every California grower plans around — written at state scale, so they stay on the state guidefrom California
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Placer County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Colfax's 900 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 900 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Colfax-wide figureread your own land →