Lassen County, in California, sits in USDA hardiness zone 7a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
A short list that earns its place here — cabbage, blackberry, california poppy, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Lassen County lies within the Shasta Cascade — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Lassen County holds more than one microclimate.
Soils and elevations shift across Lassen 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 Lassen County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Lassen County — the short answer
Lassen County, California: USDA zone 7a, about 134 days between hard freezes, across 2.9M acres.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 28
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 9
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~134
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 2.9M 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 7a is Lassen County's average, not your lot's — a low corner or a tree line moves it. Against Lassen County's 134-day season, see what your own ground reads.
One county, several growing seasons
Lassen County's hard-freeze record runs about 134 days between freezes — but that is the county-wide average, and several towns inside it carry a markedly different season in their own 30-year record: Herlong at about 173 days, Johnstonville at 165 and Milford at 165 (against the county's ~134).
Those are measured records, not estimates. If you garden in one of these pockets, plant against your own town's season rather than the county's ~134-day average.
NOAA Regional Climate Centers ACIS (1991–2020), 30-year daily minimum record. Only held-out towns carrying their own record are named — a town with no record of its own is absent rather than estimated, and a county with nothing qualifying shows no spread at all.
Heat in Lassen County
Across a year, Lassen County accumulates about 1,206 growing degree days above 50°F, about 2,551 fewer than the middle California county — ahead of 3 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.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Lassen County
Across Lassen County, the ground is predominantly Mollisols, where Devada, Petescreek, and Ravendale are the most extensive named soil series. The soil is generally well drained with a very cobbly sandy loam surface. Topsoil pH runs about 6.3–7.0, neutral. Rainfall drains through hydrologic group B soils.
Soil order
Mollisols
Drainage
Well drained
Hydric soils
3%
Soil still varies lot by lot — soil types explained.
How the ground varies across Lassen County
The USDA soil survey maps 80% of Lassen County as well drained — but another 16% drains differently: 6% moderately well drained, 4% somewhat excessively drained.
Devada is the most extensive named soil at 4% of mapped acres, then Petescreek (4%) and Ravendale (2%).
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 Lassen County
Each reading below is measured for Lassen 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 Lassen County are well drained, in hydrologic group B — 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 Lassen County runs about pH 6.3–7.0, 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
MeasuredLassen County runs about 134 days between hard freezes — a short growing season.
Long-maturing crops like melons, sweet potatoes, and winter squash can run out of runway before the first hard freeze, ripening late or not at all.
Lead with fast-maturing varieties, and stretch the season on both ends with cold frames, low tunnels, or a greenhouse.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredLassen County 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 Lassen County is in
Lassen County spans 5 EPA Level III ecoregions — Eastern Cascades Slopes and Foothills (38%), Northern Basin and Range (22%), Cascades (21%), Central Basin and Range (13%) and Sierra Nevada (6%). 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 Lassen County
We scored all 1,086 plants against Lassen County's own USDA zone 7a and its own 134-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 Lassen County?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Apr 30; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 28 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 9 — long-season crops need about 90 days of runway, quick greens only 30. In a season this compact, fast finishers and cold-hardy greens do the late work, and garlic tucked in before the freeze repays you next summer.
Documented around Lassen County
- monarch butterfly4 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Lassen County
USGS estimates 11,838 lb of Glyphosate on Lassen County farmland in 2019, its largest by weight, ahead of 2,4-d (1,269 lb) and Hexazinone (745 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 Lassen County — and how to grow with it.
We checked the federal record across Lassen County — 247 documented sites across 7 of the 9 source types we track.
The most significant on record: 5 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Lassen 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 Lassen County
Closest first, across Lassen County. Listing isn't leaking, and distance isn't exposure.
- 033N011E15P001MNitrate · 5.5 mi
- LASSEN REGIONAL SOLID WASTE MANAGEMENT AUTHORITYBrownfields · 9.1 mi
- CALTRANS PROJECT 02-0H6304Brownfields · 11.0 mi
- DIAMOND MOUNTAIN HOTSHOTSBrownfields · 11.0 mi
- LASSEN COLLEGE COGENERATION POWER PLANTBrownfields · 11.0 mi
- CITY OF SUSANVILLEPFAS · 11.4 mi
- CDCR-HIGH DESERT STATE PRISONPFAS · 11.4 mi
- TRACTOR SUPPLY COMPANY #1905Brownfields · 12.3 mi
- 035N013E25M001MNitrate · 13.3 mi
- LASSEN COUNTY ROAD DEPARTMENTBrownfields · 14.7 mi
- BUREAU OF LAND MANAGEMENT FIRESTATIONBrownfields · 14.7 mi
- ALTURAS RANCHES LLCBrownfields · 15.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Lassen 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 Lassen County.
Total Sites
247
across Lassen County
Risk Level
Elevated
Highest-severity
5 Superfund sites (none NPL-listed)
Sources Checked
across Lassen County
Severity Distribution
across Lassen County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Lassen County, two things run higher than the national average across Lassen County — Superfund (5 sites) and PFAS (3 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Lassen 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 Lassen County average
Your land is one point inside Lassen County
Everything above resolves to Lassen County as a whole — a county whose own towns’ 30-year records run 165 days between freezes in Johnstonville to 173 in Herlong. Your parcel sits at one point in that range, not in the middle of it. 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 Lassen County Average
Lassen County Average
- ●USDA Zones 7a, averaged across Lassen County
- ●One soil character for all of Lassen County
- ●Frost dates read at Lassen County's scale: May 28 to Oct 9
YOUR Parcel
- ✓Your exact zone, not Lassen County's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Lassen County
Pull a site-specific report for your exact address in Lassen County, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Lassen County averages can't show:
We read public map data around Lassen County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Lassen County average
How we know this about Lassen 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 Lassen County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Lassen County
When does frost risk typically end in Lassen County?
The last hard freeze (28°F) in Lassen County typically lands around May 28, 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 Jun 18.
How long is the growing season in Lassen County?
Measured between 28°F hard freezes, Lassen County sees about 134 frost-free days — roughly May 28 through Oct 9, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 18 to Sep 25, about 99 days.
Is the soil safe to grow vegetables in Lassen County?
The federal record around Lassen County is a meaningful one — 247 documented sites, mostly Brownfields entries (150), the nearest Nitrate record about 5.5 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.
How do gardeners stretch the season in Lassen County?
With about 134 frost-free days between hard freezes, Lassen County rewards the classic extension moves: floating row cover buys roughly two to four extra weeks at each shoulder — on this season that is a working window nearer 162 to 190 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 28 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Lassen County's scale — its 7a band and its 134-day season. Your yard writes its own version of Lassen 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 Lassen County’s own scale
9 of the readings below were taken at Lassen County's own scale — its own ~134-day span between 28°F freezes, the 3 most extensive soil series mapped here and 247 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Lassen County's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Lassen County's own 28°F hard-freeze dates and its ~134-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Lassen CountyUSDA NRCS SSURGO
- 247 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 5.5 miles outFederal environmental registers
- Lassen County's boundary and the 2,906,473 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~134-day seasonGrowable Ground crop-matching engine
- The 5 ecoregions Lassen County spans, Eastern Cascades Slopes and Foothills the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Lassen County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Lassen 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 Lassen County — the ~134 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 Lassen County's 2,906,473 acreswhy one lot differs from the next →
- Which of those 247 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 Lassen Countyread your own land →