Cohasset, California, sits in USDA hardiness zone 9b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Crops well matched to these conditions include okra, meyer lemon, california poppy, and artichoke — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Cohasset, 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 Cohasset 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 Cohasset — soil, climate, flood, and parcel records. How we handle your address.
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Cohasset — the short answer
Cohasset, California: USDA zone 9b, about 332 days between hard freezes, across 16K acres of town.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 19
- Butte County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 17
- Butte County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~332
- Butte County normal — NOAA 1991–2020, nearest to this town
- Town area
- 16K 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 Butte County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is Cohasset's average, not your lot's — a low corner or a tree line moves it. Against Cohasset's 332-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Cohasset
Each reading below is measured for Cohasset itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsCohasset runs about 332 days between hard freezes (read from Butte County, the closest normal to Cohasset) — 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
MeasuredCohasset 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 Cohasset is in
Cohasset sits in the Cascades — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Cohasset's own centroid, and it is not what its county reads: Butte County is mostly Central California Valley. The wider page above you is answering a different question about different ground.
What Grows in Cohasset
Every plant below cleared Cohasset's own zone 9b and its 332-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Cohasset?
For most of the year, no — what changes is which crops still fit the days remaining. 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 19 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 17 — long-season crops need about 90 days of runway, quick greens only 30. With almost year-round growing weather, timing is about heat and rainfall more than frost — some bench is always in play.
What's on the federal record near Cohasset
Closest first, within ~10 miles of Cohasset. Listing isn't leaking, and distance isn't exposure.
- 024N002E34E001MNitrate · 0.6 mi
- 024N002E23E001MNitrate · 1.8 mi
- 024N002E14P001MNitrate · 2.6 mi
- 023N002E08B001MNitrate · 2.9 mi
- CALTRANS D-2/EA02-3H2204Brownfields · 3.8 mi
- 023N003E06R001MNitrate · 4.1 mi
- 023N003E05C001MNitrate · 4.3 mi
- YOUTH WITH A MISSIONBrownfields · 4.6 mi
- DALE ULSHBrownfields · 5.3 mi
- 023N001E14J001MNitrate · 5.9 mi
- CAL-WATER SERVICE CO.-CHICOPFAS · 6.3 mi
- Anti-Axis ClaimMining · 6.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Cohasset'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 Cohasset.
Total Sites
126
within ~10 miles of Cohasset
Risk Level
Moderate
Highest-severity
5 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Cohasset
Severity Distribution
within ~10 miles of Cohasset
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Cohasset, two things run higher than the national average within ~10 miles of Cohasset — Nitrate (40 sites) and Brownfields (70 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Cohasset
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 Cohasset average
Your land is one point inside Cohasset
Everything above resolves to Cohasset as a whole — one PHZM band, read across 16K acres, with hard-freeze dates borrowed from Butte County’s record because no 30-year normal resolves at this town’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 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 Cohasset Average
Cohasset Average
- ●USDA Zones 9b, averaged across Cohasset
- ●One soil character for all of Cohasset
- ●Frost dates read at Cohasset's scale: Jan 19 to Dec 17
YOUR Parcel
- ✓Your exact zone, not Cohasset's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Cohasset
Pull a site-specific report for your exact address in Cohasset, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Cohasset averages can't show:
We read public map data around Cohasset — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Cohasset average
How we know this about Cohasset
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 Butte 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 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 Cohasset
When does frost risk typically end in Cohasset?
The last hard freeze (28°F) in Cohasset typically lands around Jan 19, 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 9.
When is the first frost in Cohasset?
The first hard freeze (28°F) in Cohasset typically arrives around Dec 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 3, so the watching starts about Nov 17 — about 332 days after the spring freeze cleared.
How long is the growing season in Cohasset?
Measured between 28°F hard freezes, Cohasset sees about 332 frost-free days — roughly Jan 19 through Dec 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 9 to Dec 3, about 297 days.
Is the soil safe to grow vegetables in Cohasset?
The federal record around Cohasset shows 126 documented sites, mostly Brownfields entries (70), the nearest Nitrate record about 0.6 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 Cohasset?
From about Nov 17 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 17 (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 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Cohasset's scale — its 9b band and its 332-day season. Your yard writes its own version of Cohasset'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 Cohasset’s own scale
5 of the readings below were taken at Cohasset's own scale — the 16,029 acres it covers and 126 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Cohasset's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 126 documented contamination sites on the federal record near Cohasset, the closest Nitrate record about 0.6 miles out from the town centreFederal environmental registers
- Cohasset's boundary and the 16,029 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~332-day seasonGrowable Ground crop-matching engine
- Cohasset sits in the Cascades — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Cohasset has no normal of its own, so its county's is the closest measured readfrom Butte County
- Soil character — no town-scale survey exists, so Cohasset's 16,029 acres read through its county's SSURGO summaryfrom Butte County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Butte 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 Butte County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Cohasset's 16,029 acreswhy one lot differs from the next →
- Which side of Cohasset you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 16,029 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.6 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 Cohasset-wide figureread your own land →
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