Jacksonville, Illinois, sits in USDA hardiness zone 6a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Among the crops suited to this profile: cabbage, hazelnut, lavender, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Jacksonville, 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 Jacksonville 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 Jacksonville — soil, climate, flood, and parcel records. How we handle your address.
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Jacksonville — the short answer
Jacksonville, Illinois: USDA zone 6a, about 206 days between hard freezes, across 7K acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 3
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~206
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 7K 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 6a is Jacksonville's average, not your lot's — a low corner or a tree line moves it. Against Jacksonville's 206-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Jacksonville
Each reading below is measured for Jacksonville itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredJacksonville runs about 206 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
MeasuredJacksonville sits in USDA hardiness zone 6a.
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 Jacksonville is in
Jacksonville sits in the Interior River Valleys and Hills — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Jacksonville's own centroid rather than borrowed from Morgan County.
What Grows in Jacksonville
Every plant below cleared Jacksonville's own zone 6a and its 206-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Jacksonville?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 6; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 3 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 26 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
What's on the federal record near Jacksonville
Closest first, within ~10 miles of Jacksonville. Listing isn't leaking, and distance isn't exposure.
- A Gaudio & Sons IncUnderground Storage Tanks · 650 ft
- MAIN ST EXPRESS CLEANERSBrownfields · 850 ft
- BescoUnderground Storage Tanks · 1200 ft
- Soyland Power Coop IncUnderground Storage Tanks · 1300 ft
- Zeller Bradley AUnderground Storage Tanks · 1300 ft
- Grizzly CorpUnderground Storage Tanks · 1300 ft
- Cropmate CoUnderground Storage Tanks · 1300 ft
- Western AsphaltUnderground Storage Tanks · 1300 ft
- Jacksonville Correctional CenterUnderground Storage Tanks · 1300 ft
- Clark RaymondUnderground Storage Tanks · 1300 ft
- Pisgah Coop Grain ElevUnderground Storage Tanks · 1300 ft
- Cully Gary SUnderground Storage Tanks · 1300 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Jacksonville'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 Jacksonville.
Total Sites
209
within ~10 miles of Jacksonville
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Jacksonville
Severity Distribution
within ~10 miles of Jacksonville
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Jacksonville, Underground Storage Tanks runs higher than the national average — 135 sites within ~10 miles of Jacksonville. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Jacksonville
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 Jacksonville average
Your land is one point inside Jacksonville
Everything above resolves to Jacksonville as a whole — one PHZM band and one 28°F frost record, read across 7K 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 Jacksonville Average
Jacksonville Average
- ●USDA Zones 6a, averaged across Jacksonville
- ●One soil character for all of Jacksonville
- ●Frost dates read at Jacksonville's scale: Apr 3 to Oct 26
YOUR Parcel
- ✓Your exact zone, not Jacksonville's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Jacksonville
Pull a site-specific report for your exact address in Jacksonville, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Jacksonville averages can't show:
We read public map data around Jacksonville — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Jacksonville average
How we know this about Jacksonville
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 Jacksonville’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 Jacksonville
When does frost risk typically end in Jacksonville?
The last hard freeze (28°F) in Jacksonville typically lands around Apr 3, 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 24.
When is the first frost in Jacksonville?
The first hard freeze (28°F) in Jacksonville typically arrives around Oct 26, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 12, so the watching starts about Sep 26 — about 206 days after the spring freeze cleared.
How long is the growing season in Jacksonville?
Measured between 28°F hard freezes, Jacksonville sees about 206 frost-free days — roughly Apr 3 through Oct 26, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 24 to Oct 12, about 171 days.
Is the soil safe to grow vegetables in Jacksonville?
The federal record around Jacksonville is a meaningful one — 209 documented sites, mostly Underground Storage Tanks entries (135), the nearest Underground Storage Tanks record about 0.1 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 Jacksonville?
From about Sep 26 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 26 (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 26. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Jacksonville's scale — its 6a band and its 206-day season. Your yard writes its own version of Jacksonville'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 Jacksonville’s own scale
6 of the readings below were taken at Jacksonville's own scale — its own ~206-day season between 28°F freezes, the 6,760 acres it covers and 209 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Jacksonville's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Jacksonville's own 28°F hard-freeze dates, about Apr 3 and Oct 26 and the ~206-day span between themNOAA 1991–2020 Climate Normals
- 209 documented contamination sites on the federal record near Jacksonville, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Jacksonville's boundary and the 6,760 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~206-day seasonGrowable Ground crop-matching engine
- The ecoregion at Jacksonville's own centroid, the Interior River Valleys and HillsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Jacksonville's 6,760 acres read through its county's SSURGO summaryfrom Morgan County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Morgan 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 Morgan County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Jacksonville's 6,760 acreswhy one lot differs from the next →
- Which side of Jacksonville you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 6,760 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 Jacksonville-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisJacksonville sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides