Twain, California, sits in USDA hardiness zone 8a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
The conditions favor cabbage, fig, california poppy, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Twain, 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 Twain 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 Twain — soil, climate, flood, and parcel records. How we handle your address.
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Twain — the short answer
Twain, California: USDA zone 8a, about 214 days between hard freezes, across 5K acres of town.
- USDA zone
- 8a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 14
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 14
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~214
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 5K 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 8a is Twain's average, not your lot's — a low corner or a tree line moves it. Against Twain's 214-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Twain
Each reading below is measured for Twain itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredTwain runs about 214 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredTwain sits in USDA hardiness zone 8a.
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 Twain is in
Twain sits in the Sierra Nevada — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Twain's own centroid rather than borrowed from Plumas County.
What Grows in Twain
Every plant below cleared Twain's own zone 8a and its 214-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Twain?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 17; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 14 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 14 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
What's on the federal record near Twain
Closest first, within ~10 miles of Twain. Listing isn't leaking, and distance isn't exposure.
- Unnamed LocationMining · 4.1 mi
- ShooflyMining · 4.2 mi
- Jack Forth ClaimsMining · 4.6 mi
- HillsideMining · 6.0 mi
- Fuller ClaimsMining · 6.4 mi
- FlorenceMining · 6.4 mi
- Snow White Nos 1-3Mining · 6.5 mi
- Shennandoah ClaimMining · 6.5 mi
- Valley ViewMining · 7.0 mi
- PLUMAS HEALTH & HUMAN SERVICESBrownfields · 7.0 mi
- Tip TopMining · 7.1 mi
- FEATHER RIVER COMM COLLEGE DISTRICTBrownfields · 7.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Twain'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 Twain.
Total Sites
113
within ~10 miles of Twain
Risk Level
Elevated
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Twain
Severity Distribution
within ~10 miles of Twain
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Twain, two things run higher than the national average within ~10 miles of Twain — Mining (28 sites) and Superfund (3 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.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Twain
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 Twain average
Your land is one point inside Twain
Everything above resolves to Twain as a whole — one PHZM band and one 28°F frost record, read across 5K 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 Twain Average
Twain Average
- ●USDA Zones 8a, averaged across Twain
- ●One soil character for all of Twain
- ●Frost dates read at Twain's scale: Apr 14 to Nov 14
YOUR Parcel
- ✓Your exact zone, not Twain's 8a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Twain
Pull a site-specific report for your exact address in Twain, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Twain averages can't show:
We read public map data around Twain — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Twain average
How we know this about Twain
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 Twain’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 Twain
When does frost risk typically end in Twain?
The last hard freeze (28°F) in Twain typically lands around Apr 14, 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 May 5.
When is the first frost in Twain?
The first hard freeze (28°F) in Twain typically arrives around Nov 14, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 31, so the watching starts about Oct 15 — about 214 days after the spring freeze cleared.
How long is the growing season in Twain?
Measured between 28°F hard freezes, Twain sees about 214 frost-free days — roughly Apr 14 through Nov 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 5 to Oct 31, about 179 days.
Is the soil safe to grow vegetables in Twain?
The federal record around Twain is a meaningful one — 113 documented sites, mostly Brownfields entries (72), the nearest Mining record about 4.1 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 Twain?
From about Oct 15 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 Nov 14 (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 Nov 14. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Twain's scale — its 8a band and its 214-day season. Your yard writes its own version of Twain'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 Twain’s own scale
6 of the readings below were taken at Twain's own scale — its own ~214-day season between 28°F freezes, the 4,602 acres it covers and 113 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Twain's own USDA hardiness band, zones 8aUSDA PHZM 2023
- Twain's own 28°F hard-freeze dates, about Apr 14 and Nov 14 and the ~214-day span between themNOAA 1991–2020 Climate Normals
- 113 documented contamination sites on the federal record near Twain, the closest Mining record about 4.1 miles out from the town centreFederal environmental registers
- Twain's boundary and the 4,602 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8a and a ~214-day seasonGrowable Ground crop-matching engine
- The ecoregion at Twain's own centroid, the Sierra NevadaUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Twain's 4,602 acres read through its county's SSURGO summaryfrom Plumas County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Plumas 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 Plumas County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Twain's 4,602 acreswhy one lot differs from the next →
- Which side of Twain you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,602 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Mining record about 4.1 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 Twain-wide figureread your own land →