Marseilles, Illinois, sits in USDA hardiness zone 5b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Among the crops suited to this profile: cabbage, cranberry, lavender, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Marseilles, 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 Marseilles 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 Marseilles — soil, climate, flood, and parcel records. How we handle your address.
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Marseilles — the short answer
Marseilles, Illinois: USDA zone 5b, about 204 days between hard freezes, across 6K acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 9
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~204
- 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 5b is Marseilles's average, not your lot's — a low corner or a tree line moves it. Against Marseilles's 204-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Marseilles
Each reading below is measured for Marseilles itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMarseilles runs about 204 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
MeasuredMarseilles 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 Marseilles is in
Marseilles sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Marseilles's own centroid rather than borrowed from LaSalle County.
What Grows in Marseilles
Every plant below cleared Marseilles's own zone 5b and its 204-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Marseilles?
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 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 30 — 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 Marseilles
Closest first, within ~10 miles of Marseilles. Listing isn't leaking, and distance isn't exposure.
- IL ARNG MARSEILLES TRN AREABrownfields · 1.2 mi
- US ARMY NATIONAL GUARD MARSEILLES TRAINING CENTER RANGESToxics Release Inventory · 1.2 mi
- EXELON LASALLE COUNTY STATIONBrownfields · 2.6 mi
- GLEN-GERY CORPToxics Release Inventory · 2.7 mi
- GLEN-GERY CORPBrownfields · 2.7 mi
- ASPHALT MATERIALSBrownfields · 2.8 mi
- INDEPENDENCE TUBE CORPToxics Release Inventory · 2.8 mi
- OLDCASTLE LAWN & GARDEN INCToxics Release Inventory · 2.8 mi
- PCS PHOSPHATE COMPANY, INC.Brownfields · 2.9 mi
- PCS PHOSPHATE COMPANY, INC.Toxics Release Inventory · 2.9 mi
- MARSEILLES FEED PLANTToxics Release Inventory · 2.9 mi
- ILLINI STATE PARK STPBrownfields · 2.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Marseilles'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 Marseilles.
Sources Checked
within ~10 miles of Marseilles
Severity Distribution
within ~10 miles of Marseilles
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Marseilles, two things run higher than the national average within ~10 miles of Marseilles — Superfund (7 sites) and Toxics Release Inventory (15 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.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Marseilles
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 Marseilles average
Your land is one point inside Marseilles
Everything above resolves to Marseilles 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 Marseilles Average
Marseilles Average
- ●USDA Zones 5b, averaged across Marseilles
- ●One soil character for all of Marseilles
- ●Frost dates read at Marseilles's scale: Apr 9 to Oct 30
YOUR Parcel
- ✓Your exact zone, not Marseilles's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Marseilles
Pull a site-specific report for your exact address in Marseilles, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Marseilles averages can't show:
We read public map data around Marseilles — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Marseilles average
How we know this about Marseilles
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 Marseilles’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 Marseilles
When does frost risk typically end in Marseilles?
The last hard freeze (28°F) in Marseilles typically lands around Apr 9, 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 30.
When is the first frost in Marseilles?
The first hard freeze (28°F) in Marseilles typically arrives around Oct 30, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 16, so the watching starts about Sep 30 — about 204 days after the spring freeze cleared.
How long is the growing season in Marseilles?
Measured between 28°F hard freezes, Marseilles sees about 204 frost-free days — roughly Apr 9 through Oct 30, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 30 to Oct 16, about 169 days.
Is the soil safe to grow vegetables in Marseilles?
The federal record around Marseilles is a meaningful one — 190 documented sites, mostly Underground Storage Tanks entries (108), the nearest Brownfields record about 1.2 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 Marseilles?
From about Sep 30 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 30 (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 30. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Marseilles's scale — its 5b band and its 204-day season. Your yard writes its own version of Marseilles'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 Marseilles’s own scale
6 of the readings below were taken at Marseilles's own scale — its own ~204-day season between 28°F freezes, the 5,791 acres it covers and 190 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Marseilles's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Marseilles's own 28°F hard-freeze dates, about Apr 9 and Oct 30 and the ~204-day span between themNOAA 1991–2020 Climate Normals
- 190 documented contamination sites on the federal record near Marseilles, the closest Brownfields record about 1.2 miles out from the town centreFederal environmental registers
- Marseilles's boundary and the 5,791 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~204-day seasonGrowable Ground crop-matching engine
- The ecoregion at Marseilles's own centroid, the Central Corn Belt PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Marseilles's 5,791 acres read through its county's SSURGO summaryfrom LaSalle County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom LaSalle 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 LaSalle County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Marseilles's 5,791 acreswhy one lot differs from the next →
- Which side of Marseilles you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 5,791 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 1.2 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 Marseilles-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisMarseilles sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides