Penryn, California, sits in USDA hardiness zone 9b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Well-matched crops include okra, meyer lemon, california poppy, and artichoke, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Penryn, 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 Penryn 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 Penryn — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Penryn — the short answer
Penryn, California: USDA zone 9b, about 290 days between hard freezes, across 1K acres of town.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 23
- Placer County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 10
- Placer County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~290
- Placer County normal — NOAA 1991–2020, nearest to this town
- Town area
- 1K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Placer County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is Penryn's average, not your lot's — a low corner or a tree line moves it. Against Penryn's 290-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Penryn
Each reading below is measured for Penryn itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsPenryn runs about 290 days between hard freezes (read from Placer County, the closest normal to Penryn) — 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
MeasuredPenryn sits in USDA hardiness zone 9b.
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 Penryn is in
Penryn sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Penryn's own centroid, and it is not what its county reads: Placer County is mostly Sierra Nevada. The wider page above you is answering a different question about different ground.
What Grows in Penryn
Every plant below cleared Penryn's own zone 9b and its 290-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Penryn?
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 26; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 23 (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. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
What's on the federal record near Penryn
Closest first, within ~10 miles of Penryn. Listing isn't leaking, and distance isn't exposure.
- GEORGE BOEGER DBA GB TRUCK REPAIRBrownfields · 1700 ft
- PENRYN AUTOBrownfields · 1700 ft
- HURLIMAN BOAT & REPAIRBrownfields · 1700 ft
- Elizabeth MineMining · 0.7 mi
- CAL'S MARINEBrownfields · 0.7 mi
- Alabama MineMining · 0.7 mi
- AlabamaMining · 0.7 mi
- ChicagoMining · 0.7 mi
- Alabama-California MineMining · 0.8 mi
- PENRYN GAS & LIQUORBrownfields · 0.8 mi
- PENRYN GAS & LIQUORUnderground Storage Tanks · 0.8 mi
- PENRYN 76Underground Storage Tanks · 0.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Penryn'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 Penryn.
Total Sites
1,554
within ~10 miles of Penryn
Risk Level
High
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Penryn
Severity Distribution
within ~10 miles of Penryn
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Penryn, two things run higher than the national average within ~10 miles of Penryn — Brownfields (1,261 sites) and Mining (115 sites). 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.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Penryn
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 Penryn average
Your land is one point inside Penryn
Everything above resolves to Penryn as a whole — one PHZM band, read across 1K acres, with hard-freeze dates borrowed from Placer County’s record because no 30-year normal resolves at this town’s own centroid. 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 Penryn Average
Penryn Average
- ●USDA Zones 9b, averaged across Penryn
- ●One soil character for all of Penryn
- ●Frost dates read at Penryn's scale: Feb 23 to Dec 10
YOUR Parcel
- ✓Your exact zone, not Penryn's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Penryn
Pull a site-specific report for your exact address in Penryn, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Penryn averages can't show:
We read public map data around Penryn — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Penryn average
How we know this about Penryn
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 Placer County’s record, because none resolves here; 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 Penryn
When does frost risk typically end in Penryn?
The last hard freeze (28°F) in Penryn typically lands around Feb 23, 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 16.
When is the first frost in Penryn?
The first hard freeze (28°F) in Penryn 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 290 days after the spring freeze cleared.
How long is the growing season in Penryn?
Measured between 28°F hard freezes, Penryn sees about 290 frost-free days — roughly Feb 23 through Dec 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 16 to Nov 26, about 255 days.
Is the soil safe to grow vegetables in Penryn?
The federal record around Penryn runs heavier than most — 1,554 documented sites, mostly Brownfields entries (1,261), the nearest Brownfields record about 0.3 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do I protect my plants from frost in Penryn?
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 Penryn's scale — its 9b band and its 290-day season. Your yard writes its own version of Penryn'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 Penryn’s own scale
5 of the readings below were taken at Penryn's own scale — the 1,218 acres it covers and 1,554 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Penryn's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 1,554 documented contamination sites on the federal record near Penryn, the closest Brownfields record about 0.3 miles out from the town centreFederal environmental registers
- Penryn's boundary and the 1,218 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~290-day seasonGrowable Ground crop-matching engine
- Penryn sits in the Central California Foothills and Coastal Mountains — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Penryn has no normal of its own, so its county's is the closest measured readfrom Placer County
- Soil character — no town-scale survey exists, so Penryn's 1,218 acres read through its county's SSURGO summaryfrom Placer County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Placer 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 Placer County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Penryn's 1,218 acreswhy one lot differs from the next →
- Which side of Penryn you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,218 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Penryn-wide figureread your own land →
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