Hartley, California, sits in USDA hardiness zone 9b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
These conditions suit okra, meyer lemon, california poppy, and artichoke — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Hartley, 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 Hartley 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 Hartley — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Hartley — the short answer
Hartley, California: USDA zone 9b, about 335 days between hard freezes, across 4K acres of town.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 15
- Solano County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 16
- Solano County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~335
- Solano County normal — NOAA 1991–2020, nearest to this town
- Town area
- 4K 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 Solano County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is Hartley's average, not your lot's — a low corner or a tree line moves it. Against Hartley's 335-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Hartley
Each reading below is measured for Hartley itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsHartley runs about 335 days between hard freezes (read from Solano County, the closest normal to Hartley) — 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
MeasuredHartley 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 Hartley is in
Hartley sits in the Central California Valley — EPA Level III, inside the wider Mediterranean California. That is read at Hartley's own centroid rather than borrowed from Solano County.
What Grows in Hartley
Every plant below cleared Hartley's own zone 9b and its 335-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Hartley?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Jan 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jan 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 16 — long-season crops need about 90 days of runway, quick greens only 30. Here the calendar nearly circles: cool-season crops take the winter shift, and the next window is always close.
What's on the federal record near Hartley
Closest first, within ~10 miles of Hartley. Listing isn't leaking, and distance isn't exposure.
- Oates' Country StoreUnderground Storage Tanks · 1400 ft
- 700 CROCKER DR OWNER LLCBrownfields · 0.6 mi
- MATHESON TRI-GASBrownfields · 0.9 mi
- LIQUID CARBONIC INDUSTRIES MEDICAL CORPToxics Release Inventory · 0.9 mi
- 007N001W35M001MNitrate · 0.9 mi
- SANTA FE PACIFIC PIPELINE ELMIRA BOOSTER STNBrownfields · 1.0 mi
- MARIANI PACKINGBrownfields · 1.0 mi
- MARIANI PACKINGToxics Release Inventory · 1.0 mi
- FRANK'S SEPTIC SERVICE, INCBrownfields · 1.1 mi
- SUPERIOR SIGN SYSTEMSBrownfields · 1.2 mi
- MASTER PLASTICS INCBrownfields · 1.3 mi
- CLARK PEST CONTROLBrownfields · 1.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Hartley'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 Hartley.
Total Sites
760
within ~10 miles of Hartley
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Hartley
Severity Distribution
within ~10 miles of Hartley
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Hartley, Brownfields runs higher than the national average — 620 sites within ~10 miles of Hartley. 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 Hartley
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 Hartley average
Your land is one point inside Hartley
Everything above resolves to Hartley as a whole — one PHZM band, read across 4K acres, with hard-freeze dates borrowed from Solano 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 Hartley Average
Hartley Average
- ●USDA Zones 9b, averaged across Hartley
- ●One soil character for all of Hartley
- ●Frost dates read at Hartley's scale: Jan 15 to Dec 16
YOUR Parcel
- ✓Your exact zone, not Hartley's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Hartley
Pull a site-specific report for your exact address in Hartley, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Hartley averages can't show:
We read public map data around Hartley — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Hartley average
How we know this about Hartley
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 Solano 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 Hartley
When does frost risk typically end in Hartley?
The last hard freeze (28°F) in Hartley typically lands around Jan 15, 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 Feb 5.
When is the first frost in Hartley?
The first hard freeze (28°F) in Hartley typically arrives around Dec 16, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 2, so the watching starts about Nov 16 — about 335 days after the spring freeze cleared.
How long is the growing season in Hartley?
Measured between 28°F hard freezes, Hartley sees about 335 frost-free days — roughly Jan 15 through Dec 16, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 5 to Dec 2, about 300 days.
Is the soil safe to grow vegetables in Hartley?
The federal record around Hartley is a meaningful one — 760 documented sites, mostly Brownfields entries (620), the nearest Underground Storage Tanks record about 0.3 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 Hartley?
From about Nov 16 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 16 (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 16. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Hartley's scale — its 9b band and its 335-day season. Your yard writes its own version of Hartley'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 Hartley’s own scale
5 of the readings below were taken at Hartley's own scale — the 4,142 acres it covers and 760 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Hartley's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 760 documented contamination sites on the federal record near Hartley, the closest Underground Storage Tanks record about 0.3 miles out from the town centreFederal environmental registers
- Hartley's boundary and the 4,142 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~335-day seasonGrowable Ground crop-matching engine
- The ecoregion at Hartley's own centroid, the Central California ValleyUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Hartley has no normal of its own, so its county's is the closest measured readfrom Solano County
- Soil character — no town-scale survey exists, so Hartley's 4,142 acres read through its county's SSURGO summaryfrom Solano County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Solano 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 Solano County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Hartley's 4,142 acreswhy one lot differs from the next →
- Which side of Hartley you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,142 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 Hartley-wide figureread your own land →
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