Forbestown, California, sits in USDA hardiness zone 9a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
The conditions favor artichoke, fig, california poppy, and cabbage, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Forbestown, 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 Forbestown 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 Forbestown — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Forbestown — the short answer
Forbestown, California: USDA zone 9a, about 303 days between hard freezes, across 4K acres of town.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Dec 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~303
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 4K 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 9a is Forbestown's average, not your lot's — a low corner or a tree line moves it. Against Forbestown's 303-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Forbestown
Each reading below is measured for Forbestown itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredForbestown runs about 303 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
MeasuredForbestown 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 Forbestown is in
Forbestown sits in the Sierra Nevada — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Forbestown'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 Forbestown
Every plant below cleared Forbestown's own zone 9a and its 303-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Forbestown?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Jan 13; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 10 (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. Here the calendar nearly circles: cool-season crops take the winter shift, and the next window is always close.
What's on the federal record near Forbestown
Closest first, within ~10 miles of Forbestown. Listing isn't leaking, and distance isn't exposure.
- Gold Bank Consolidated QuartzMining · 1700 ft
- Forbestown Consolidated Gold MinesMining · 0.5 mi
- GOLD BANK MINESuperfund · 0.6 mi
- SOUTH FORK POWER PROJECTBrownfields · 0.7 mi
- Carlisle MineMining · 1.2 mi
- P.U.P. Zenith MineMining · 1.8 mi
- Strouse DepositMining · 2.1 mi
- P.U.P. MineMining · 2.2 mi
- P.U.P.MineMining · 2.2 mi
- StrouseMining · 2.2 mi
- 019N006E16C001MNitrate · 2.4 mi
- Unnamed OccurrenceMining · 3.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Forbestown'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 Forbestown.
Total Sites
74
within ~10 miles of Forbestown
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Forbestown
Severity Distribution
within ~10 miles of Forbestown
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Forbestown, two things run higher than the national average within ~10 miles of Forbestown — Mining (29 sites) and PFAS (3 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
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 Forbestown
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 Forbestown average
Your land is one point inside Forbestown
Everything above resolves to Forbestown as a whole — one PHZM band and one 28°F frost record, read across 4K 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 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 Forbestown Average
Forbestown Average
- ●USDA Zones 9a, averaged across Forbestown
- ●One soil character for all of Forbestown
- ●Frost dates read at Forbestown's scale: Feb 10 to Dec 10
YOUR Parcel
- ✓Your exact zone, not Forbestown's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Forbestown
Pull a site-specific report for your exact address in Forbestown, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Forbestown averages can't show:
We read public map data around Forbestown — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Forbestown average
How we know this about Forbestown
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 Forbestown’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 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 Forbestown
When does frost risk typically end in Forbestown?
The last hard freeze (28°F) in Forbestown typically lands around Feb 10, 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 3.
When is the first frost in Forbestown?
The first hard freeze (28°F) in Forbestown 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 303 days after the spring freeze cleared.
How long is the growing season in Forbestown?
Measured between 28°F hard freezes, Forbestown sees about 303 frost-free days — roughly Feb 10 through Dec 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 3 to Nov 26, about 268 days.
Is the soil safe to grow vegetables in Forbestown?
The federal record around Forbestown is a meaningful one — 74 documented sites, mostly Mining entries (29), the nearest Mining record about 0.3 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 I protect my plants from frost in Forbestown?
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 Forbestown's scale — its 9a band and its 303-day season. Your yard writes its own version of Forbestown'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 Forbestown’s own scale
6 of the readings below were taken at Forbestown's own scale — its own ~303-day season between 28°F freezes, the 4,015 acres it covers and 74 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Forbestown's own USDA hardiness band, zones 9aUSDA PHZM 2023
- Forbestown's own 28°F hard-freeze dates, about Feb 10 and Dec 10 and the ~303-day span between themNOAA 1991–2020 Climate Normals
- 74 documented contamination sites on the federal record near Forbestown, the closest Mining record about 0.3 miles out from the town centreFederal environmental registers
- Forbestown's boundary and the 4,015 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~303-day seasonGrowable Ground crop-matching engine
- Forbestown sits in the Sierra Nevada — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Forbestown's 4,015 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 Forbestown's 4,015 acreswhy one lot differs from the next →
- Which side of Forbestown you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,015 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Mining record about 0.3 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 Forbestown-wide figureread your own land →