Logan County, in Illinois, sits in USDA hardiness zone 6a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Among the crops suited to this profile: cabbage, hazelnut, lavender, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Logan County holds more than one microclimate.
Soils and elevations shift across Logan 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 Logan County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Logan County — the short answer
Logan County, Illinois: USDA zone 6a, about 206 days between hard freezes, across 396K acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 4
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 27
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~206
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 396K 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 Logan County's average, not your lot's — a low corner or a tree line moves it. Against Logan County's 206-day season, see what your own ground reads.
Heat in Logan County
Across a year, Logan County accumulates about 3,367 growing degree days above 50°F, about 16 fewer than the middle Illinois county — ahead of 48 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 Logan County
Across Logan County, the ground is predominantly Mollisols, where Sable, Ipava, and Sawmill are the most extensive named soil series. The soil is generally poorly drained with a silt loam surface. Topsoil pH runs about 6.0–6.7, slightly acidic. Rainfall drains through hydrologic group B/D soils.
Soil order
Mollisols
Drainage
Poorly drained
Prime farmland
50%
Hydric soils
34%
Soil still varies lot by lot — soil types explained.
How the ground varies across Logan County
The USDA soil survey maps 35% of Logan County as poorly drained — but another 65% drains differently: 30% well drained, 28% somewhat poorly drained.
Sable is the most extensive named soil at 19% of mapped acres, then Ipava (19%) and Sawmill (6%).
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 Logan County
Each reading below is measured for Logan 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 Logan County are 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 Logan County runs about pH 6.0–6.7, 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
MeasuredLogan County 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
MeasuredLogan 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 Logan County is in
Logan 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 Logan County
We scored all 1,086 plants against Logan County's own USDA zone 6a and its own 206-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 Logan 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 7; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 4 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 27 — 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 gets applied to farmland in Logan County
USGS estimates 403,636 lb of Glyphosate on Logan County farmland in 2019, its largest by weight, ahead of Atrazine (181,604 lb) and Metolachlor & Metolachlor-s (167,951 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 Logan County — and how to grow with it.
We checked the federal record across Logan County — 242 documented sites across 8 of the 9 source types we track.
The most significant on record: 3 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Logan County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Logan County
Closest first, across Logan County. Listing isn't leaking, and distance isn't exposure.
- CUSTOM CREATIONSBrownfields · 1100 ft
- VULCAN MATERIALS COBrownfields · 0.5 mi
- IL American - LincolnPFAS · 0.7 mi
- THOMPSON AUTOBODYBrownfields · 0.7 mi
- Art Truck & AutoUnderground Storage Tanks · 0.8 mi
- United Water IllinoisUnderground Storage Tanks · 0.8 mi
- PEPL-LINCOLN M&RBrownfields · 0.9 mi
- Contractors Ready Mix IncUnderground Storage Tanks · 0.9 mi
- Logan County Highway DeptUnderground Storage Tanks · 0.9 mi
- Quality Glass CoUnderground Storage Tanks · 1.0 mi
- Larson Mfg CoUnderground Storage Tanks · 1.0 mi
- Goodyear TireUnderground Storage Tanks · 1.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Logan 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 Logan County.
Total Sites
242
across Logan County
Risk Level
Elevated
Highest-severity
3 Superfund sites (none NPL-listed)
Severity Distribution
across Logan County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Logan County, two things run higher than the national average across Logan County — CAFO (8 sites) and Superfund (3 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Logan 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 Logan County average
Your land is one point inside Logan County
Everything above resolves to Logan County as a whole — one PHZM band and one county frost record, read across 396K 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 Logan County Average
Logan County Average
- ●USDA Zones 6a, averaged across Logan County
- ●One soil character for all of Logan County
- ●Frost dates read at Logan County's scale: Apr 4 to Oct 27
YOUR Parcel
- ✓Your exact zone, not Logan County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Logan County
Pull a site-specific report for your exact address in Logan County, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Logan County averages can't show:
We read public map data around Logan County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Logan County average
How we know this about Logan 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 Logan County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Logan County
When does frost risk typically end in Logan County?
The last hard freeze (28°F) in Logan County typically lands around Apr 4, 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 25.
How long is the growing season in Logan County?
Measured between 28°F hard freezes, Logan County sees about 206 frost-free days — roughly Apr 4 through Oct 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 25 to Oct 13, about 171 days.
Is the soil safe to grow vegetables in Logan County?
The federal record around Logan County is a meaningful one — 242 documented sites, mostly Underground Storage Tanks entries (145), the nearest Brownfields 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.
Everything above is measured at Logan County's scale — its 6a band and its 206-day season. Your yard writes its own version of Logan 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 Logan County’s own scale
8 of the readings below were taken at Logan County's own scale — its own ~206-day span between 28°F freezes, the 3 most extensive soil series mapped here and 242 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Logan County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Logan County's own 28°F hard-freeze dates and its ~206-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Logan CountyUSDA NRCS SSURGO
- 242 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Brownfields record about 0.2 miles outFederal environmental registers
- Logan County's boundary and the 395,553 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~206-day seasonGrowable Ground crop-matching engine
- Logan County sitting wholly inside the Central Corn Belt PlainsUS EPA Level III Ecoregions
- Which agricultural compounds go onto Logan 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 Logan County — the ~206 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 Logan County's 395,553 acreswhy one lot differs from the next →
- Which of those 242 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 Logan Countyread your own land →