Joliet, Illinois, sits in USDA hardiness zone 5b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
The conditions favor cabbage, blueberry, lavender, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Joliet, 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 Joliet 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 Joliet — soil, climate, flood, and parcel records. How we handle your address.
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Joliet — the short answer
Joliet, Illinois: USDA zone 5b, about 210 days between hard freezes, across 42K acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 6
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~210
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 42K 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 5b is Joliet's average, not your lot's — a low corner or a tree line moves it. Against Joliet's 210-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Joliet
Each reading below is measured for Joliet itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredJoliet runs about 210 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredJoliet sits in USDA hardiness zone 5b.
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 Joliet is in
Joliet sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Joliet's own centroid rather than borrowed from Will County.
What Grows in Joliet
Every plant below cleared Joliet's own zone 5b and its 210-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Joliet?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 9; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 6 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 2 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
Documented around Joliet
Spotted lanternfly documented 16 miles from Joliet, first recorded 2023. What to watch for.
What's on the federal record near Joliet
Closest first, within ~10 miles of Joliet. Listing isn't leaking, and distance isn't exposure.
- Herald NewsUnderground Storage Tanks · 550 ft
- US ARMY RESERVE CENTERBrownfields · 800 ft
- Il Dept Of CorrectionsUnderground Storage Tanks · 1100 ft
- BOC GASESToxics Release Inventory · 1500 ft
- Canteen CorpUnderground Storage Tanks · 1600 ft
- Brandon Road Lock & DamUnderground Storage Tanks · 1900 ft
- Blue Ribbon Products CoUnderground Storage Tanks · 1900 ft
- DUKES OF JOLIETBrownfields · 1900 ft
- U S Auto GlassUnderground Storage Tanks · 1900 ft
- Thornton Oil 302Underground Storage Tanks · 1900 ft
- Joliet Nissan IncUnderground Storage Tanks · 2000 ft
- FMS 12 JolietUnderground Storage Tanks · 2000 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Joliet'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 Joliet.
Sources Checked
within ~10 miles of Joliet
Severity Distribution
within ~10 miles of Joliet
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Joliet, two things run higher than the national average within ~10 miles of Joliet — Superfund (20 sites) and PFAS (12 sites). That's not a problem with your land — it's information about it.
Superfund: Superfund sites represent the most severe contamination in the federal system.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Joliet
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 Joliet average
Your land is one point inside Joliet
Everything above resolves to Joliet as a whole — one PHZM band and one 28°F frost record, read across 42K 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 Joliet Average
Joliet Average
- ●USDA Zones 5b, averaged across Joliet
- ●One soil character for all of Joliet
- ●Frost dates read at Joliet's scale: Apr 6 to Nov 2
YOUR Parcel
- ✓Your exact zone, not Joliet's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Joliet
Pull a site-specific report for your exact address in Joliet, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Joliet averages can't show:
We read public map data around Joliet — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Joliet average
How we know this about Joliet
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 Joliet’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 Joliet
When does frost risk typically end in Joliet?
The last hard freeze (28°F) in Joliet typically lands around Apr 6, 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 Apr 27.
When is the first frost in Joliet?
The first hard freeze (28°F) in Joliet typically arrives around Nov 2, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 19, so the watching starts about Oct 3 — about 210 days after the spring freeze cleared.
How long is the growing season in Joliet?
Measured between 28°F hard freezes, Joliet sees about 210 frost-free days — roughly Apr 6 through Nov 2, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 27 to Oct 19, about 175 days.
Is the soil safe to grow vegetables in Joliet?
The federal record around Joliet runs heavier than most — 1,146 documented sites, mostly Brownfields entries (507), the nearest Underground Storage Tanks record about 0.1 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 Joliet?
From about Oct 3 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 Nov 2 (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 Nov 2. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Joliet's scale — its 5b band and its 210-day season. Your yard writes its own version of Joliet'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 Joliet’s own scale
7 of the readings below were taken at Joliet's own scale — its own ~210-day season between 28°F freezes, the 42,423 acres it covers and 1,146 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Joliet's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Joliet's own 28°F hard-freeze dates, about Apr 6 and Nov 2 and the ~210-day span between themNOAA 1991–2020 Climate Normals
- 1,146 documented contamination sites on the federal record near Joliet, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Joliet's boundary and the 42,423 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~210-day seasonGrowable Ground crop-matching engine
- The ecoregion at Joliet's own centroid, the Central Corn Belt PlainsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Jolietlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Joliet's 42,423 acres read through its county's SSURGO summaryfrom Will County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Will 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 Will County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Joliet's 42,423 acreswhy one lot differs from the next →
- Which side of Joliet you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 42,423 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 Joliet-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisJoliet sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides