LaSalle County, in 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.
A short list that earns its place here — cabbage, hazelnut, lavender, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
LaSalle County holds more than one microclimate.
Soils and elevations shift across LaSalle County, so your frost dates and drainage aren't the county average. 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 LaSalle County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
LaSalle County — the short answer
LaSalle County, Illinois: USDA zone 6a, about 210 days between hard freezes, across 726K acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 7
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 3
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~210
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 726K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 LaSalle County's average, not your lot's — a low corner or a tree line moves it. Against LaSalle County's 210-day season, see what your own ground reads.
Heat in LaSalle County
Across a year, LaSalle County accumulates about 3,020 growing degree days above 50°F, about 363 fewer than the middle Illinois county — ahead of 20 of Illinois’s 102 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in LaSalle County
Across LaSalle County, the ground is predominantly Mollisols, where Muscatune, Drummer, and Sable are the most extensive named soil series. The soil is generally somewhat poorly drained with a silt loam surface. Topsoil pH runs about 6.2–6.7, slightly acidic. Rainfall drains through hydrologic group B/D soils.
Soil order
Mollisols
Drainage
Somewhat poorly drained
Prime farmland
51%
Hydric soils
30%
Soil still varies lot by lot — soil types explained.
How the ground varies across LaSalle County
The USDA soil survey maps 40% of LaSalle County as somewhat poorly drained — but another 58% drains differently: 29% poorly drained, 14% moderately well drained.
Muscatune is the most extensive named soil at 9% of mapped acres, then Drummer (8%) and Sable (7%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in LaSalle County
Each reading below is measured for LaSalle County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across LaSalle County are somewhat poorly drained, in hydrologic group B/D — ground that sheds water slowly.
Beds can stay saturated for days after heavy rain, and the roots of most vegetables, berries, and fruit trees suffocate or rot in soil that never drains.
Raised beds or mounded rows lift roots above the wet zone; choose water-tolerant crops for the lowest spots.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across LaSalle County runs about pH 6.2–6.7, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredLaSalle County 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
MeasuredLaSalle County 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 LaSalle County is in
LaSalle County sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. One consistent ecological setting across the whole county.
What Grows in LaSalle County
We scored all 1,086 plants against LaSalle County's own USDA zone 6a and its own 210-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Illinois profile.
Is it too late to plant in LaSalle County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 10; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 7 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 3 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
Documented around LaSalle County
- Japanese beetle2 documented records
- monarch butterfly130 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in LaSalle County
USGS estimates 561,739 lb of Glyphosate on LaSalle County farmland in 2019, its largest by weight, ahead of Acetochlor (264,060 lb) and Atrazine (248,313 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across LaSalle County — and how to grow with it.
We checked the federal record across LaSalle County — 809 documented sites across 7 of the 9 source types we track.
The most significant on record: 22 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
LaSalle County carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near LaSalle County
Closest first, across LaSalle County. Listing isn't leaking, and distance isn't exposure.
- US SILICA COBrownfields · 2300 ft
- Village of NaplateUnderground Storage Tanks · 0.8 mi
- La Salle County Highway Dept.Underground Storage Tanks · 0.9 mi
- States Land Improvement Corp.Underground Storage Tanks · 1.0 mi
- PILKINGTON NORTH AMERICABrownfields · 1.1 mi
- PILKINGTON NORTH AMERICASuperfund · 1.1 mi
- PILKINGTON NORTH AMERICAToxics Release Inventory · 1.1 mi
- Ottawa Industrial Sand CoUnderground Storage Tanks · 1.1 mi
- CARVS CHEMICAL CO OTTAWA LABBrownfields · 1.2 mi
- CSX TRANSPORTATION INCBrownfields · 1.2 mi
- A&T AUTO ELECTRIC INCBrownfields · 1.3 mi
- CARGILL INCBrownfields · 1.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from LaSalle County'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 LaSalle County.
Sources Checked
across LaSalle County
Severity Distribution
across LaSalle County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around LaSalle County, two things run higher than the national average across LaSalle County — Superfund (22 sites) and Toxics Release Inventory (56 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 LaSalle County
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 LaSalle County average
Your land is one point inside LaSalle County
Everything above resolves to LaSalle County as a whole — one PHZM band and one county frost record, read across 726K 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 county 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 county average.
Your Lot vs the LaSalle County Average
LaSalle County Average
- ●USDA Zones 6a, averaged across LaSalle County
- ●One soil character for all of LaSalle County
- ●Frost dates read at LaSalle County's scale: Apr 7 to Nov 3
YOUR Parcel
- ✓Your exact zone, not LaSalle County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in LaSalle County
Pull a site-specific report for your exact address in LaSalle County, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that LaSalle County averages can't show:
We read public map data around LaSalle County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the LaSalle County average
How we know this about LaSalle County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where LaSalle County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about LaSalle County
When does frost risk typically end in LaSalle County?
The last hard freeze (28°F) in LaSalle County typically lands around Apr 7, 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 28.
How long is the growing season in LaSalle County?
Measured between 28°F hard freezes, LaSalle County sees about 210 frost-free days — roughly Apr 7 through Nov 3, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 28 to Oct 20, about 175 days.
Is the soil safe to grow vegetables in LaSalle County?
The federal record around LaSalle County runs heavier than most — 809 documented sites, mostly Underground Storage Tanks entries (455), the nearest Brownfields record about 0.4 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.
Everything above is measured at LaSalle County's scale — its 6a band and its 210-day season. Your yard writes its own version of LaSalle County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Illinois's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at LaSalle County’s own scale
9 of the readings below were taken at LaSalle County's own scale — its own ~210-day span between 28°F freezes, the 3 most extensive soil series mapped here and 809 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- LaSalle County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- LaSalle County's own 28°F hard-freeze dates and its ~210-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in LaSalle CountyUSDA NRCS SSURGO
- 809 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Brownfields record about 0.4 miles outFederal environmental registers
- LaSalle County's boundary and the 726,475 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~210-day seasonGrowable Ground crop-matching engine
- LaSalle County sitting wholly inside the Central Corn Belt PlainsUS EPA Level III Ecoregions
- Open occurrence records documented in LaSalle County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto LaSalle County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Illinois grower plans around — written at state scale, so they stay on the state guidefrom Illinois
What this page can’t tell you
- How the season shifts across LaSalle County — the ~210 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among LaSalle County's 726,475 acreswhy one lot differs from the next →
- Which of those 809 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over LaSalle Countyread your own land →