Portola, California, sits in USDA hardiness zone 6b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Among the crops suited to this profile: cabbage, blackberry, california poppy, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Portola, 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 Portola 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 Portola — soil, climate, flood, and parcel records. How we handle your address.
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Portola — the short answer
Portola, California: USDA zone 6b, about 130 days between hard freezes, across 3K acres of city.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 24
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 1
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~130
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 3K 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 Portola's average, not your lot's — a low corner or a tree line moves it. Against Portola's 130-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Portola
Each reading below is measured for Portola itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredPortola runs about 130 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
MeasuredPortola 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 Portola is in
Portola sits in the Sierra Nevada — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Portola's own centroid rather than borrowed from Plumas County.
What Grows in Portola
Every plant below cleared Portola's own zone 6b and its 130-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Portola?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Apr 26; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 24 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 1 — long-season crops need about 90 days of runway, quick greens only 30. Short seasons reward decisiveness — quick-maturing varieties late, hardy greens under cover, and next year’s garlic in the ground before it closes.
What's on the federal record near Portola
Closest first, within ~10 miles of Portola. Listing isn't leaking, and distance isn't exposure.
- PHIL ALLEGRIBrownfields · 0.6 mi
- PACIFIC BELLBrownfields · 0.7 mi
- Sierra Energy #36Underground Storage Tanks · 0.8 mi
- DILLON'S MOBILE REPAIRBrownfields · 0.8 mi
- KS MarketUnderground Storage Tanks · 0.8 mi
- TOMS SIERRA CO INC DBA SIERRA SUPER STOP 36Brownfields · 0.8 mi
- TROY'S AUTOMOTIVE SERVICEBrownfields · 0.8 mi
- PORTOLA AUTOMOTIVEBrownfields · 0.8 mi
- PORTOLA SENIOR LPBrownfields · 0.9 mi
- DOLLAR GENERAL #16097Brownfields · 0.9 mi
- CITY OF PORTOLA-PUBLIC WORKSBrownfields · 1.0 mi
- UNION PACIFIC RAILROAD PORTOLABrownfields · 1.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Portola'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 Portola.
Sources Checked
within ~10 miles of Portola
Severity Distribution
within ~10 miles of Portola
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Portola, Brownfields runs higher than the national average — 42 sites within ~10 miles of Portola. That's not a problem with your land — it's information about 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 Portola
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 Portola average
Your land is one point inside Portola
Everything above resolves to Portola as a whole — one PHZM band and one 28°F frost record, read across 3K 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 city 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 Portola Average
Portola Average
- ●USDA Zones 6b, averaged across Portola
- ●One soil character for all of Portola
- ●Frost dates read at Portola's scale: May 24 to Oct 1
YOUR Parcel
- ✓Your exact zone, not Portola's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Portola
Pull a site-specific report for your exact address in Portola, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Portola averages can't show:
We read public map data around Portola — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Portola average
How we know this about Portola
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Portola’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 city grain anywhere on this page — there is no city-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 Portola
When does frost risk typically end in Portola?
The last hard freeze (28°F) in Portola typically lands around May 24, 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 14.
When is the first frost in Portola?
The first hard freeze (28°F) in Portola typically arrives around Oct 1, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 17, so the watching starts about Sep 1 — about 130 days after the spring freeze cleared.
How long is the growing season in Portola?
Measured between 28°F hard freezes, Portola sees about 130 frost-free days — roughly May 24 through Oct 1, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 14 to Sep 17, about 95 days.
Is the soil safe to grow vegetables in Portola?
The federal record around Portola shows 52 documented sites, mostly Brownfields entries (42), the nearest Brownfields 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 gardeners stretch the season in Portola?
With about 130 frost-free days between hard freezes, Portola 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 158 to 186 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 24 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Portola's scale — its 6b band and its 130-day season. Your yard writes its own version of Portola'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 Portola’s own scale
6 of the readings below were taken at Portola's own scale — its own ~130-day season between 28°F freezes, the 3,460 acres it covers and 52 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Portola's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Portola's own 28°F hard-freeze dates, about May 24 and Oct 1 and the ~130-day span between themNOAA 1991–2020 Climate Normals
- 52 documented contamination sites on the federal record near Portola, the closest Brownfields record about 0.6 miles out from the town centreFederal environmental registers
- Portola's boundary and the 3,460 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~130-day seasonGrowable Ground crop-matching engine
- The ecoregion at Portola's own centroid, the Sierra NevadaUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Portola's 3,460 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 Portola's 3,460 acreswhy one lot differs from the next →
- Which side of Portola you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,460 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Portola-wide figureread your own land →