Cromberg, California, sits in USDA hardiness zone 7a — a zone band wide enough that plant choice, not possibility, is the interesting question.
On paper, cabbage, pawpaw, california poppy, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Cromberg, 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 Cromberg 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 Cromberg — soil, climate, flood, and parcel records. How we handle your address.
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Cromberg — the short answer
Cromberg, California: USDA zone 7a, about 172 days between hard freezes, across 6K acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 28
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~172
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 6K 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 7a is Cromberg's average, not your lot's — a low corner or a tree line moves it. Against Cromberg's 172-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Cromberg
Each reading below is measured for Cromberg itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCromberg runs about 172 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredCromberg 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 Cromberg is in
Cromberg sits in the Sierra Nevada — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Cromberg's own centroid rather than borrowed from Plumas County.
What Grows in Cromberg
Every plant below cleared Cromberg's own zone 7a and its 172-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Cromberg?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 31; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 28 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 17 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Cromberg
Closest first, within ~10 miles of Cromberg. Listing isn't leaking, and distance isn't exposure.
- SIERRA PACIFIC INDUSTRIESBrownfields · 1.0 mi
- Unnamed LocationMining · 4.5 mi
- UNION PACIFIC RAILROAD - KEDDIEBrownfields · 5.5 mi
- CALIFORNIA STATE PARKS PLUMAS EUREKA SPBrownfields · 6.2 mi
- PLUMAS EUREKA STATE HISTORIC PARKSuperfund · 6.2 mi
- U.S. Smelting, Refining, and Mining Co.Mining · 6.4 mi
- U.S. SmeltingMining · 6.4 mi
- WalkerMining · 6.4 mi
- Us Smelting Refining & Mining CoMining · 6.5 mi
- Walker MineMining · 6.5 mi
- USDA USFS R05 BECKWOURTH RANGER DISTRICTBrownfields · 6.5 mi
- OhioMining · 6.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Cromberg'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 Cromberg.
Total Sites
32
within ~10 miles of Cromberg
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Cromberg
Severity Distribution
within ~10 miles of Cromberg
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Cromberg, Mining runs higher than the national average — 21 sites within ~10 miles of Cromberg. 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.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Cromberg
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 Cromberg average
Your land is one point inside Cromberg
Everything above resolves to Cromberg as a whole — one PHZM band and one 28°F frost record, read across 6K 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 Cromberg Average
Cromberg Average
- ●USDA Zones 7a, averaged across Cromberg
- ●One soil character for all of Cromberg
- ●Frost dates read at Cromberg's scale: Apr 28 to Oct 17
YOUR Parcel
- ✓Your exact zone, not Cromberg's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Cromberg
Pull a site-specific report for your exact address in Cromberg, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Cromberg averages can't show:
We read public map data around Cromberg — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Cromberg average
How we know this about Cromberg
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 Cromberg’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 Cromberg
When does frost risk typically end in Cromberg?
The last hard freeze (28°F) in Cromberg typically lands around Apr 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 May 19.
When is the first frost in Cromberg?
The first hard freeze (28°F) in Cromberg typically arrives around Oct 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 3, so the watching starts about Sep 17 — about 172 days after the spring freeze cleared.
How long is the growing season in Cromberg?
Measured between 28°F hard freezes, Cromberg sees about 172 frost-free days — roughly Apr 28 through Oct 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 19 to Oct 3, about 137 days.
Is the soil safe to grow vegetables in Cromberg?
The federal record around Cromberg is a meaningful one — 32 documented sites, mostly Mining entries (21), the nearest Brownfields record about 1.0 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 Cromberg?
From about Sep 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 Oct 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 Oct 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Cromberg's scale — its 7a band and its 172-day season. Your yard writes its own version of Cromberg'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 Cromberg’s own scale
6 of the readings below were taken at Cromberg's own scale — its own ~172-day season between 28°F freezes, the 5,779 acres it covers and 32 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Cromberg's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Cromberg's own 28°F hard-freeze dates, about Apr 28 and Oct 17 and the ~172-day span between themNOAA 1991–2020 Climate Normals
- 32 documented contamination sites on the federal record near Cromberg, the closest Brownfields record about 1.0 miles out from the town centreFederal environmental registers
- Cromberg's boundary and the 5,779 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~172-day seasonGrowable Ground crop-matching engine
- The ecoregion at Cromberg's own centroid, the Sierra NevadaUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Cromberg's 5,779 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 Cromberg's 5,779 acreswhy one lot differs from the next →
- Which side of Cromberg you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 5,779 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 1.0 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 Cromberg-wide figureread your own land →