Imperial, California, sits in USDA hardiness zone 10a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
On paper, avocado, meyer lemon, tomato, and artichoke all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Imperial, 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 Imperial 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 Imperial — soil, climate, flood, and parcel records. How we handle your address.
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Imperial — the short answer
Imperial, California: USDA zone 10a, about 344 days between hard freezes, across 4K acres of city.
- USDA zone
- 10a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 15
- Imperial County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 25
- Imperial County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~344
- Imperial County normal — NOAA 1991–2020, nearest to this town
- City 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 Imperial County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 10a is Imperial's average, not your lot's — a low corner or a tree line moves it. Against Imperial's 344-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Imperial
Each reading below is measured for Imperial itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsImperial runs about 344 days between hard freezes (read from Imperial County, the closest normal to Imperial) — 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
MeasuredImperial sits in USDA hardiness zone 10a.
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 Imperial is in
Imperial sits in the Sonoran Basin and Range — EPA Level III, inside the wider North American Deserts. That is read at Imperial's own centroid rather than borrowed from Imperial County.
What Grows in Imperial
Plants matched to Imperial's USDA zones 10a, ordered by how much hardiness margin each has here — the ones with room to spare at both ends of this town's band lead. Each links to its full growing profile.
Is it too late to plant in Imperial?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. 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 25 — long-season crops need about 90 days of runway, quick greens only 30. And with a calendar this mild, the honest answer is that planting barely stops — winter opens seasons colder regions never see.
What's on the federal record near Imperial
Closest first, within ~10 miles of Imperial. Listing isn't leaking, and distance isn't exposure.
- ROSS FLYING SERVICE INCBrownfields · 1200 ft
- FOOTE PHOTO COBrownfields · 1300 ft
- TRANSPORTATION SECURITY ADMINBrownfields · 1500 ft
- MOKULELE AIRLINESBrownfields · 1500 ft
- A FARMER SERVICE CORP DBA VISCO FLYING COBrownfields · 1500 ft
- AUTOZONE #4187Brownfields · 1900 ft
- BRENNTAG PACIFIC, INCBrownfields · 2000 ft
- BRENNTAG PACIFIC, INCToxics Release Inventory · 2000 ft
- CITY OF IMPERIAL POLICE DEPARTMENTBrownfields · 2000 ft
- KENNY STRICKLAND INCBrownfields · 2100 ft
- COUNTY OF IMPERIAL ROAD DIST 3Brownfields · 2100 ft
- WFS - IMPERIAL (VALLEY CHEMICAL)Brownfields · 2300 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Imperial'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 Imperial.
Sources Checked
within ~10 miles of Imperial
Severity Distribution
within ~10 miles of Imperial
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Imperial, two things run higher than the national average within ~10 miles of Imperial — Brownfields (531 sites) and PFAS (6 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Imperial
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 Imperial average
Your land is one point inside Imperial
Everything above resolves to Imperial as a whole — one PHZM band, read across 4K acres, with hard-freeze dates borrowed from Imperial County’s record because no 30-year normal resolves at this city’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 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 Imperial Average
Imperial Average
- ●USDA Zones 10a, averaged across Imperial
- ●One soil character for all of Imperial
- ●Frost dates read at Imperial's scale: Jan 15 to Dec 25
YOUR Parcel
- ✓Your exact zone, not Imperial's 10a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Imperial
Pull a site-specific report for your exact address in Imperial, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Imperial averages can't show:
We read public map data around Imperial — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Imperial average
How we know this about Imperial
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 Imperial 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 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 Imperial
When does frost risk typically end in Imperial?
The last hard freeze (28°F) in Imperial 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 Imperial?
The first hard freeze (28°F) in Imperial typically arrives around Dec 25, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 11, so the watching starts about Nov 25 — about 344 days after the spring freeze cleared.
How long is the growing season in Imperial?
Measured between 28°F hard freezes, Imperial sees about 344 frost-free days — roughly Jan 15 through Dec 25, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 5 to Dec 11, about 309 days.
Is the soil safe to grow vegetables in Imperial?
The federal record around Imperial is a meaningful one — 601 documented sites, mostly Brownfields entries (531), the nearest Brownfields record about 0.2 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 Imperial?
From about Nov 25 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 25 (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 25. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Imperial's scale — its 10a band and its 344-day season. Your yard writes its own version of Imperial'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 Imperial’s own scale
4 of the readings below were taken at Imperial's own scale — the 4,036 acres it covers and 601 documented sites around it; 6 are borrowed from a wider read, named and linked below.
Measured here
- Imperial's own USDA hardiness band, zones 10aUSDA PHZM 2023
- 601 documented contamination sites on the federal record near Imperial, the closest Brownfields record about 0.2 miles out from the town centreFederal environmental registers
- Imperial's boundary and the 4,036 acres inside itUS Census TIGER/Line 2025
- The ecoregion at Imperial's own centroid, the Sonoran Basin and RangeUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Imperial has no normal of its own, so its county's is the closest measured readfrom Imperial County
- Soil character — no town-scale survey exists, so Imperial's 4,036 acres read through its county's SSURGO summaryfrom Imperial County
- The candidate plant list — California's curated set, filtered to this zone band and re-ordered by how much margin each has herefrom California
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Imperial 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 Imperial County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Imperial's 4,036 acreswhy one lot differs from the next →
- Which side of Imperial you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,036 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.2 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 Imperial-wide figureread your own land →