Iron Horse, California, sits in USDA hardiness zone 6b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
These conditions suit cabbage, blackberry, california poppy, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Iron Horse, 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 Iron Horse 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 Iron Horse — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Iron Horse — the short answer
Iron Horse, California: USDA zone 6b, about 139 days between hard freezes, across 5K acres of town.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 3
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~139
- 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 6b is Iron Horse's average, not your lot's — a low corner or a tree line moves it. Against Iron Horse's 139-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Iron Horse
Each reading below is measured for Iron Horse itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredIron Horse runs about 139 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
MeasuredIron Horse sits in USDA hardiness zone 6b.
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 Iron Horse is in
Iron Horse sits in the Sierra Nevada — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Iron Horse's own centroid rather than borrowed from Plumas County.
What Grows in Iron Horse
Every plant below cleared Iron Horse's own zone 6b and its 139-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Iron Horse?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Apr 19; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 3 — long-season crops need about 90 days of runway, quick greens only 30. When the window is tight, the fall moves are quick ones — baby greens, radishes, and garlic set for next season.
What's on the federal record near Iron Horse
Closest first, within ~10 miles of Iron Horse. Listing isn't leaking, and distance isn't exposure.
- ValentineMining · 1.1 mi
- PLUMAS COUNTY - PUBLIC WORKSBrownfields · 1.7 mi
- EASTERN PLUMAS HEALTH CAREBrownfields · 1.8 mi
- WHITE CAP READY MIX INCBrownfields · 1.8 mi
- PORTOLA WWTPBrownfields · 1.8 mi
- CITY OF PORTOLABrownfields · 1.9 mi
- RIGGS & SMITH ENTERPRISES INC DBA SIERRA GARAGEBrownfields · 1.9 mi
- DAVID LEE HUMPHREY/DBA CRESCENT TOWBrownfields · 1.9 mi
- COATES INC DBA COATES TIRE CENTER ALSO LES SCHWAB TIRE CENTERBrownfields · 1.9 mi
- DOLLAR GENERAL #16097Brownfields · 1.9 mi
- CALPECO PORTOLA SUBSTATION & OPERATION CENTERBrownfields · 1.9 mi
- KIBBLE ENTERPRISES INC DBA PORTOLA VILLAGE PHARMACYBrownfields · 1.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Iron Horse'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 Iron Horse.
Sources Checked
within ~10 miles of Iron Horse
Severity Distribution
within ~10 miles of Iron Horse
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Iron Horse, Brownfields runs higher than the national average — 42 sites within ~10 miles of Iron Horse. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Iron Horse
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 Iron Horse average
Your land is one point inside Iron Horse
Everything above resolves to Iron Horse 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 Iron Horse Average
Iron Horse Average
- ●USDA Zones 6b, averaged across Iron Horse
- ●One soil character for all of Iron Horse
- ●Frost dates read at Iron Horse's scale: May 17 to Oct 3
YOUR Parcel
- ✓Your exact zone, not Iron Horse's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Iron Horse
Pull a site-specific report for your exact address in Iron Horse, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Iron Horse averages can't show:
We read public map data around Iron Horse — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Iron Horse average
How we know this about Iron Horse
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 Iron Horse’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 Iron Horse
When does frost risk typically end in Iron Horse?
The last hard freeze (28°F) in Iron Horse typically lands around May 17, 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 7.
When is the first frost in Iron Horse?
The first hard freeze (28°F) in Iron Horse typically arrives around Oct 3, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 19, so the watching starts about Sep 3 — about 139 days after the spring freeze cleared.
How long is the growing season in Iron Horse?
Measured between 28°F hard freezes, Iron Horse sees about 139 frost-free days — roughly May 17 through Oct 3, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 7 to Sep 19, about 104 days.
Is the soil safe to grow vegetables in Iron Horse?
The federal record around Iron Horse shows 52 documented sites, mostly Brownfields entries (42), the nearest Mining record about 1.1 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 gardeners stretch the season in Iron Horse?
With about 139 frost-free days between hard freezes, Iron Horse 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 167 to 195 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 17 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Iron Horse's scale — its 6b band and its 139-day season. Your yard writes its own version of Iron Horse'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 Iron Horse’s own scale
6 of the readings below were taken at Iron Horse's own scale — its own ~139-day season between 28°F freezes, the 4,956 acres it covers and 52 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Iron Horse's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Iron Horse's own 28°F hard-freeze dates, about May 17 and Oct 3 and the ~139-day span between themNOAA 1991–2020 Climate Normals
- 52 documented contamination sites on the federal record near Iron Horse, the closest Mining record about 1.1 miles out from the town centreFederal environmental registers
- Iron Horse's boundary and the 4,956 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~139-day seasonGrowable Ground crop-matching engine
- The ecoregion at Iron Horse's own centroid, the Sierra NevadaUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Iron Horse's 4,956 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 Iron Horse's 4,956 acreswhy one lot differs from the next →
- Which side of Iron Horse you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,956 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Mining record about 1.1 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 Iron Horse-wide figureread your own land →