Alexander County, in Illinois, sits in USDA hardiness zone 7a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Expect cabbage, hazelnut, california poppy, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Alexander County lies within the Shawnee Hills / Southern Illinois (Little Egypt) — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Alexander County holds more than one microclimate.
Soils and elevations shift across Alexander 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 Alexander County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Alexander County — the short answer
Alexander County, Illinois: USDA zone 7a, about 244 days between hard freezes, across 151K acres.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 17
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 16
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~244
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 151K 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 7a is Alexander County's average, not your lot's — a low corner or a tree line moves it. Against Alexander County's 244-day season, see what your own ground reads.
Heat and winter chill in Alexander County
Across a year, Alexander County accumulates about 4,261 growing degree days above 50°F, about 878 more than the middle Illinois county — ahead of every other Illinois county. 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.
Winter banks about 2,452 hours below 45°F. Chill is what tells a fruit tree its dormancy is over, and it is set by climate rather than by anything you can build.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Alexander County
Across Alexander County, the ground is predominantly Alfisols, where Stookey, Darwin, and Menfro are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 5.9–6.7, slightly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Alfisols
Drainage
Well drained
Prime farmland
14%
Hydric soils
44%
Soil still varies lot by lot — soil types explained.
How the ground varies across Alexander County
The USDA soil survey maps 41% of Alexander County as well drained — but another 51% drains differently: 23% poorly drained, 13% somewhat poorly drained.
Stookey is the most extensive named soil at 13% of mapped acres, then Darwin (8%) and Menfro (8%).
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 Alexander County
Each reading below is measured for Alexander 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 Alexander County are well drained, in hydrologic group B — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Alexander County runs about pH 5.9–6.7, 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
Wet ground
MeasuredAbout 44% of Alexander County is mapped as hydric — wetland — soil.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Season length
MeasuredAlexander County runs about 244 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
The kind of country Alexander County is in
Alexander County spans 3 EPA Level III ecoregions — Interior River Valleys and Hills (56%), Mississippi Alluvial Plain (39%) and Interior Plateau (6%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Alexander County
We scored all 1,086 plants against Alexander County's own USDA zone 7a and its own 244-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 Alexander County?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Feb 17; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 16 — 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.
What gets applied to farmland in Alexander County
USGS estimates 41,847 lb of Glyphosate on Alexander County farmland in 2019, its largest by weight, ahead of Metolachlor & Metolachlor-s (33,000 lb) and Metolachlor-s (23,780 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 Alexander County — and how to grow with it.
We checked the federal record across Alexander County — 74 documented sites across 5 of the 9 source types we track.
The most significant on record: 3 Superfund sites. 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 Alexander 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 Alexander County
Closest first, across Alexander County. Listing isn't leaking, and distance isn't exposure.
- Ford Bruce & CliffordUnderground Storage Tanks · 1.0 mi
- County Maint YardUnderground Storage Tanks · 1.0 mi
- Watson Oil Products IncUnderground Storage Tanks · 1.0 mi
- Fill-Up MartUnderground Storage Tanks · 1.1 mi
- Jones Service StationUnderground Storage Tanks · 1.1 mi
- 16S 2W- 4.8bNitrate · 2.5 mi
- 16S 2E- 7.7fNitrate · 3.8 mi
- Pulaski/Sandusky Rd and IL-127Nitrate · 4.7 mi
- Huffman's ServiceUnderground Storage Tanks · 5.6 mi
- Butcher BlockUnderground Storage Tanks · 5.6 mi
- Egyptian School Dist #5Underground Storage Tanks · 5.9 mi
- Unimin Specialty Minerals IncUnderground Storage Tanks · 5.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Alexander 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 Alexander County.
Sources Checked
across Alexander County
Severity Distribution
across Alexander County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Alexander County, Superfund runs higher than the national average — 3 sites across Alexander County. 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.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Alexander 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 Alexander County average
Your land is one point inside Alexander County
Everything above resolves to Alexander County as a whole — one PHZM band and one county frost record, read across 151K 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 Alexander County Average
Alexander County Average
- ●USDA Zones 7a, averaged across Alexander County
- ●One soil character for all of Alexander County
- ●Frost dates read at Alexander County's scale: Mar 17 to Nov 16
YOUR Parcel
- ✓Your exact zone, not Alexander County's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Alexander County
Pull a site-specific report for your exact address in Alexander County, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Alexander County averages can't show:
We read public map data around Alexander County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Alexander County average
How we know this about Alexander 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 Alexander County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Alexander County
When does frost risk typically end in Alexander County?
The last hard freeze (28°F) in Alexander County typically lands around Mar 17, 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 7.
How long is the growing season in Alexander County?
Measured between 28°F hard freezes, Alexander County sees about 244 frost-free days — roughly Mar 17 through Nov 16, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 7 to Nov 2, about 209 days.
Is the soil safe to grow vegetables in Alexander County?
The federal record around Alexander County is a meaningful one — 74 documented sites, mostly Underground Storage Tanks entries (45), the nearest Underground Storage Tanks record about 1.0 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 Alexander County's scale — its 7a band and its 244-day season. Your yard writes its own version of Alexander 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 Alexander County’s own scale
8 of the readings below were taken at Alexander County's own scale — its own ~244-day span between 28°F freezes, the 3 most extensive soil series mapped here and 74 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Alexander County's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Alexander County's own 28°F hard-freeze dates and its ~244-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Alexander CountyUSDA NRCS SSURGO
- 74 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 1.0 miles outFederal environmental registers
- Alexander County's boundary and the 150,652 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~244-day seasonGrowable Ground crop-matching engine
- The 3 ecoregions Alexander County spans, Interior River Valleys and Hills the largestUS EPA Level III Ecoregions
- Which agricultural compounds go onto Alexander 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 Alexander County — the ~244 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 Alexander County's 150,652 acreswhy one lot differs from the next →
- Which of those 74 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 Alexander Countyread your own land →