Stockton, Illinois, sits in USDA hardiness zone 5a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
On paper, cabbage, cranberry, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Stockton, 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 Stockton 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 Stockton — soil, climate, flood, and parcel records. How we handle your address.
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Stockton — the short answer
Stockton, Illinois: USDA zone 5a, about 183 days between hard freezes, across 1K acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 19
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 19
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~183
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 5a is Stockton's average, not your lot's — a low corner or a tree line moves it. Against Stockton's 183-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Stockton
Each reading below is measured for Stockton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredStockton runs about 183 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredStockton sits in USDA hardiness zone 5a.
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 Stockton is in
Stockton sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Stockton's own centroid, and it is not what its county reads: Jo Daviess County is mostly Driftless Area. The wider page above you is answering a different question about different ground.
What Grows in Stockton
Every plant below cleared Stockton's own zone 5a and its 183-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Stockton?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 22; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 19 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 19 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Stockton
Closest first, within ~10 miles of Stockton. Listing isn't leaking, and distance isn't exposure.
- Stockton YardUnderground Storage Tanks · 650 ft
- Stockton Schools Bus GarageUnderground Storage Tanks · 700 ft
- Johnston Feed Ser IncUnderground Storage Tanks · 1500 ft
- ILDOT DIV OF HIGHWAYSBrownfields · 1600 ft
- Bocker Motors IncUnderground Storage Tanks · 1700 ft
- Previous US Post OfficeUnderground Storage Tanks · 1700 ft
- Atwood Auto/Stockton PlantUnderground Storage Tanks · 1700 ft
- Stockton Travel CenterUnderground Storage Tanks · 1800 ft
- NICOR GASBrownfields · 1800 ft
- Casey's General Store #2505Underground Storage Tanks · 1800 ft
- Express Lane Gas & Food Mart, Inc.Underground Storage Tanks · 1800 ft
- Express Lane Gas & Food MartUnderground Storage Tanks · 1900 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Stockton'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 Stockton.
Total Sites
84
within ~10 miles of Stockton
Risk Level
Moderate
Highest-severity
4 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Stockton
Severity Distribution
within ~10 miles of Stockton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Stockton, two things run higher than the national average within ~10 miles of Stockton — CAFO (9 sites) and Underground Storage Tanks (59 sites). That's not a problem with your land — it's information about it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Stockton
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 Stockton average
Your land is one point inside Stockton
Everything above resolves to Stockton as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Stockton Average
Stockton Average
- ●USDA Zones 5a, averaged across Stockton
- ●One soil character for all of Stockton
- ●Frost dates read at Stockton's scale: Apr 19 to Oct 19
YOUR Parcel
- ✓Your exact zone, not Stockton's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Stockton
Pull a site-specific report for your exact address in Stockton, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Stockton averages can't show:
We read public map data around Stockton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Stockton average
How we know this about Stockton
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 Stockton’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 Stockton
When does frost risk typically end in Stockton?
The last hard freeze (28°F) in Stockton typically lands around Apr 19, 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 May 10.
When is the first frost in Stockton?
The first hard freeze (28°F) in Stockton typically arrives around Oct 19, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 5, so the watching starts about Sep 19 — about 183 days after the spring freeze cleared.
How long is the growing season in Stockton?
Measured between 28°F hard freezes, Stockton sees about 183 frost-free days — roughly Apr 19 through Oct 19, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 10 to Oct 5, about 148 days.
Is the soil safe to grow vegetables in Stockton?
The federal record around Stockton shows 84 documented sites, mostly Underground Storage Tanks entries (59), the nearest Underground Storage Tanks record about 0.1 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 I protect my plants from frost in Stockton?
From about Sep 19 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 Oct 19 (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 Oct 19. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Stockton's scale — its 5a band and its 183-day season. Your yard writes its own version of Stockton'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 Stockton’s own scale
6 of the readings below were taken at Stockton's own scale — its own ~183-day season between 28°F freezes, the 1,201 acres it covers and 84 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Stockton's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Stockton's own 28°F hard-freeze dates, about Apr 19 and Oct 19 and the ~183-day span between themNOAA 1991–2020 Climate Normals
- 84 documented contamination sites on the federal record near Stockton, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Stockton's boundary and the 1,201 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~183-day seasonGrowable Ground crop-matching engine
- Stockton sits in the Central Corn Belt Plains — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Stockton's 1,201 acres read through its county's SSURGO summaryfrom Jo Daviess County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Jo Daviess County
- The growing challenges every Illinois grower plans around — written at state scale, so they stay on the state guidefrom Illinois
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Jo Daviess County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Stockton's 1,201 acreswhy one lot differs from the next →
- Which side of Stockton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,201 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Stockton-wide figureread your own land →
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