Tehama County, in California, sits in USDA hardiness zone 9b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Reliable performers under these conditions include okra, meyer lemon, california poppy, and artichoke; what your own ground favors still comes down to its soil, sun, and drainage.
Tehama County lies within the Sacramento Valley and the California Central Valley — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Tehama County holds more than one microclimate.
Soils and elevations shift across Tehama County, so your frost dates and drainage aren't the county average. 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 Tehama County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Tehama County — the short answer
Tehama County, California: USDA zone 9b, about 325 days between hard freezes, across 1.9M acres.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 22
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Dec 13
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~325
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.9M acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 9b is Tehama County's average, not your lot's — a low corner or a tree line moves it. Against Tehama County's 325-day season, see what your own ground reads.
Heat and winter chill in Tehama County
Across a year, Tehama County accumulates about 4,642 growing degree days above 50°F, about 885 more than the middle California county — ahead of 45 of California’s 57 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Winter banks about 1,172 hours below 45°F, 15 fewer than the California middle of 1,187. Chill is what tells a fruit tree its dormancy is over, and it is set by climate rather than by anything you can build.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Tehama County
Across Tehama County, the ground is predominantly Alfisols, where Toomes, Newville, and Sheetiron are the most extensive named soil series. The soil is generally well drained with a gravelly loam surface. Topsoil pH runs about 5.9–6.5, slightly acidic. Rainfall drains through hydrologic group D soils.
Soil order
Alfisols
Drainage
Well drained
Hydric soils
2%
Soil still varies lot by lot — soil types explained.
How the ground varies across Tehama County
The USDA soil survey maps 85% of Tehama County as well drained — but another 15% drains differently: 7% somewhat excessively drained, 4% excessively drained.
Toomes is the most extensive named soil at 13% of mapped acres, then Newville (13%) and Sheetiron (8%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Tehama County
Each reading below is measured for Tehama County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Tehama County are well drained, in hydrologic group D — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Tehama County runs about pH 5.9–6.5, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredTehama County runs about 325 days between hard freezes — 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
MeasuredTehama County sits in USDA hardiness zone 9b.
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 Tehama County is in
Tehama County spans 4 EPA Level III ecoregions — Central California Foothills and Coastal Mountains (54%), Central California Valley (16%), Cascades (16%) and Klamath Mountains/California High North Coast Range (14%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Tehama County
We scored all 1,086 plants against Tehama County's own USDA zone 9b and its own 325-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's California profile.
Is it too late to plant in Tehama County?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Jan 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jan 22 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 13 — long-season crops need about 90 days of runway, quick greens only 30. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
Documented around Tehama County
- monarch butterfly1 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Tehama County
USGS estimates 93,589 lb of Glyphosate on Tehama County farmland in 2019, its largest by weight, ahead of Propiconazole (5,740 lb) and 2,4-d (4,740 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Tehama County — and how to grow with it.
We checked the federal record across Tehama County — 832 documented sites across 6 of the 9 source types we track.
The most significant on record: 3 Toxics Release Inventory facilities. Active industrial facilities reporting chemical releases to air, water, and land.
There's a meaningful federal record across Tehama County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Tehama County
Closest first, across Tehama County. Listing isn't leaking, and distance isn't exposure.
- 026N003W04F002MNitrate · 1.2 mi
- 026N003W04F001MNitrate · 1.3 mi
- PJ HELICOPTERSBrownfields · 1.4 mi
- TEHAMA COUNTY OPPORTUNITY CENTER DBA NORTH VALLEY SERVICESBrownfields · 1.4 mi
- TEHAMA COUNTY MOSQUITO & VECTOR CONTROLBrownfields · 1.4 mi
- TRIPLE R GASBrownfields · 1.5 mi
- FOOTHILL READY MIXBrownfields · 1.6 mi
- DESOTEC US LLCBrownfields · 1.7 mi
- LASSEN MEDICAL CLINIC RED BLUFFBrownfields · 1.7 mi
- DIGNITY HEALTH WOMEN'S HEALTH SERVICESBrownfields · 1.7 mi
- WOUND HEALING AND HYPERBARIC MEDICINE CENTERBrownfields · 1.7 mi
- DIGNITY HEALTH DBA ST ELIZABETH COMM HOSPITALBrownfields · 1.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Tehama County'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 Tehama County.
Total Sites
832
across Tehama County
Risk Level
Elevated
Highest-severity
3 Toxics Release Inventory facilities
Sources Checked
across Tehama County
Severity Distribution
across Tehama County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Tehama County, two things run higher than the national average across Tehama County — Mining (86 sites) and Nitrate (396 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.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Tehama County
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 Tehama County average
Your land is one point inside Tehama County
Everything above resolves to Tehama County as a whole — one PHZM band and one county frost record, read across 1.9M 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 county 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 county average.
Your Lot vs the Tehama County Average
Tehama County Average
- ●USDA Zones 9b, averaged across Tehama County
- ●One soil character for all of Tehama County
- ●Frost dates read at Tehama County's scale: Jan 22 to Dec 13
YOUR Parcel
- ✓Your exact zone, not Tehama County's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Tehama County
Pull a site-specific report for your exact address in Tehama County, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Tehama County averages can't show:
We read public map data around Tehama County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Tehama County average
How we know this about Tehama County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Tehama County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Tehama County
When does frost risk typically end in Tehama County?
The last hard freeze (28°F) in Tehama County typically lands around Jan 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 Feb 12.
How long is the growing season in Tehama County?
Measured between 28°F hard freezes, Tehama County sees about 325 frost-free days — roughly Jan 22 through Dec 13, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 12 to Nov 29, about 290 days.
Is the soil safe to grow vegetables in Tehama County?
The federal record around Tehama County is a meaningful one — 832 documented sites, mostly Nitrate entries (396), the nearest Nitrate record about 1.2 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
Everything above is measured at Tehama County's scale — its 9b band and its 325-day season. Your yard writes its own version of Tehama County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads California's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Tehama County’s own scale
9 of the readings below were taken at Tehama County's own scale — its own ~325-day span between 28°F freezes, the 3 most extensive soil series mapped here and 832 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Tehama County's own USDA hardiness band, zones 9bUSDA PHZM 2023
- Tehama County's own 28°F hard-freeze dates and its ~325-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Tehama CountyUSDA NRCS SSURGO
- 832 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 1.2 miles outFederal environmental registers
- Tehama County's boundary and the 1,887,446 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~325-day seasonGrowable Ground crop-matching engine
- The 4 ecoregions Tehama County spans, Central California Foothills and Coastal Mountains the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Tehama County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Tehama County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every California grower plans around — written at state scale, so they stay on the state guidefrom California
What this page can’t tell you
- How the season shifts across Tehama County — the ~325 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Tehama County's 1,887,446 acreswhy one lot differs from the next →
- Which of those 832 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Tehama Countyread your own land →