Herrin, Illinois, sits in USDA hardiness zone 7a — a zone band wide enough that plant choice, not possibility, is the interesting question.
A short list that earns its place here — cabbage, hazelnut, california poppy, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in Herrin, 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 Herrin 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 Herrin — soil, climate, flood, and parcel records. How we handle your address.
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Herrin — the short answer
Herrin, Illinois: USDA zone 7a, about 224 days between hard freezes, across 6K acres of city.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 27
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 6
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~224
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 6K 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 7a is Herrin's average, not your lot's — a low corner or a tree line moves it. Against Herrin's 224-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Herrin
Each reading below is measured for Herrin itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredHerrin runs about 224 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
MeasuredHerrin sits in USDA hardiness zone 7a.
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 Herrin is in
Herrin sits in the Interior River Valleys and Hills — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Herrin's own centroid rather than borrowed from Williamson County.
What Grows in Herrin
Every plant below cleared Herrin's own zone 7a and its 224-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Herrin?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 27; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 27 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 6 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
What's on the federal record near Herrin
Closest first, within ~10 miles of Herrin. Listing isn't leaking, and distance isn't exposure.
- Hucks #239Underground Storage Tanks · 850 ft
- Herrin BP #233Underground Storage Tanks · 1000 ft
- Norge Co Magic Chef CorpUnderground Storage Tanks · 1100 ft
- Amoco Ss #5539Underground Storage Tanks · 1300 ft
- Chittyville Elementary SchUnderground Storage Tanks · 1400 ft
- S Il Vault CoUnderground Storage Tanks · 1400 ft
- Cw Transport IncUnderground Storage Tanks · 1400 ft
- Marion Il RcagUnderground Storage Tanks · 1400 ft
- Herrin HospitalUnderground Storage Tanks · 1700 ft
- Southern BeverageUnderground Storage Tanks · 1900 ft
- Km 121-7263Underground Storage Tanks · 2100 ft
- KERR MCGEEBrownfields · 2100 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Herrin'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 Herrin.
Sources Checked
within ~10 miles of Herrin
Severity Distribution
within ~10 miles of Herrin
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Herrin, two things run higher than the national average within ~10 miles of Herrin — PFAS (6 sites) and Underground Storage Tanks (252 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Herrin
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 Herrin average
Your land is one point inside Herrin
Everything above resolves to Herrin as a whole — one PHZM band and one 28°F frost record, read across 6K 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 Herrin Average
Herrin Average
- ●USDA Zones 7a, averaged across Herrin
- ●One soil character for all of Herrin
- ●Frost dates read at Herrin's scale: Mar 27 to Nov 6
YOUR Parcel
- ✓Your exact zone, not Herrin's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Herrin
Pull a site-specific report for your exact address in Herrin, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Herrin averages can't show:
We read public map data around Herrin — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Herrin average
How we know this about Herrin
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 Herrin’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 Herrin
When does frost risk typically end in Herrin?
The last hard freeze (28°F) in Herrin typically lands around Mar 27, 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 17.
When is the first frost in Herrin?
The first hard freeze (28°F) in Herrin typically arrives around Nov 6, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 23, so the watching starts about Oct 7 — about 224 days after the spring freeze cleared.
How long is the growing season in Herrin?
Measured between 28°F hard freezes, Herrin sees about 224 frost-free days — roughly Mar 27 through Nov 6, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 17 to Oct 23, about 189 days.
Is the soil safe to grow vegetables in Herrin?
The federal record around Herrin is a meaningful one — 408 documented sites, mostly Underground Storage Tanks entries (252), the nearest Underground Storage Tanks 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 Herrin?
From about Oct 7 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 6 (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 6. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Herrin's scale — its 7a band and its 224-day season. Your yard writes its own version of Herrin'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 Herrin’s own scale
6 of the readings below were taken at Herrin's own scale — its own ~224-day season between 28°F freezes, the 6,191 acres it covers and 408 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Herrin's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Herrin's own 28°F hard-freeze dates, about Mar 27 and Nov 6 and the ~224-day span between themNOAA 1991–2020 Climate Normals
- 408 documented contamination sites on the federal record near Herrin, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Herrin's boundary and the 6,191 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~224-day seasonGrowable Ground crop-matching engine
- The ecoregion at Herrin'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 Herrin's 6,191 acres read through its county's SSURGO summaryfrom Williamson County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Williamson 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 Williamson County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Herrin's 6,191 acreswhy one lot differs from the next →
- Which side of Herrin you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 6,191 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 Herrin-wide figureread your own land →