Glenwood, Illinois, sits in USDA hardiness zone 6a — a zone band wide enough that plant choice, not possibility, is the interesting question.
The conditions favor cabbage, hazelnut, lavender, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Glenwood, 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 Glenwood 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 Glenwood — soil, climate, flood, and parcel records. How we handle your address.
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Glenwood — the short answer
Glenwood, Illinois: USDA zone 6a, about 216 days between hard freezes, across 2K acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 5
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~216
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 2K 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 6a is Glenwood's average, not your lot's — a low corner or a tree line moves it. Against Glenwood's 216-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Glenwood
Each reading below is measured for Glenwood itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredGlenwood runs about 216 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
MeasuredGlenwood 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 Glenwood is in
Glenwood sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Glenwood's own centroid rather than borrowed from Cook County.
What Grows in Glenwood
Every plant below cleared Glenwood's own zone 6a and its 216-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Glenwood?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Mar 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 5 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 7 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
Documented around Glenwood
Spotted lanternfly documented 12 miles from Glenwood, first recorded 2023. What to watch for.
What's on the federal record near Glenwood
Closest first, within ~10 miles of Glenwood. Listing isn't leaking, and distance isn't exposure.
- GLENWOODPFAS · 900 ft
- Construction SiteUnderground Storage Tanks · 1800 ft
- Village of GlenwoodUnderground Storage Tanks · 1900 ft
- Glenwoodie CcUnderground Storage Tanks · 0.5 mi
- 35N14E- 3.3c1Nitrate · 0.6 mi
- Your Local Gas, Inc.Underground Storage Tanks · 0.6 mi
- GLENWOOD WOODS SOUTH FOREST PRESERVEBrownfields · 0.6 mi
- Booster Station #2Underground Storage Tanks · 0.7 mi
- 35N14E-10.1g1Nitrate · 0.7 mi
- ROLL SERVICES INCToxics Release Inventory · 0.7 mi
- 2 SCIENCE RDToxics Release Inventory · 0.7 mi
- LANDAUER INCBrownfields · 0.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Glenwood'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 Glenwood.
Sources Checked
within ~10 miles of Glenwood
Severity Distribution
within ~10 miles of Glenwood
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Glenwood, two things run higher than the national average within ~10 miles of Glenwood — Superfund (73 sites) and PFAS (40 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.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Glenwood
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 Glenwood average
Your land is one point inside Glenwood
Everything above resolves to Glenwood as a whole — one PHZM band and one 28°F frost record, read across 2K 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 town 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 Glenwood Average
Glenwood Average
- ●USDA Zones 6a, averaged across Glenwood
- ●One soil character for all of Glenwood
- ●Frost dates read at Glenwood's scale: Apr 5 to Nov 7
YOUR Parcel
- ✓Your exact zone, not Glenwood's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Glenwood
Pull a site-specific report for your exact address in Glenwood, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Glenwood averages can't show:
We read public map data around Glenwood — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Glenwood average
How we know this about Glenwood
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Glenwood’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 town grain anywhere on this page — there is no town-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 Glenwood
When does frost risk typically end in Glenwood?
The last hard freeze (28°F) in Glenwood typically lands around Apr 5, 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 26.
When is the first frost in Glenwood?
The first hard freeze (28°F) in Glenwood typically arrives around Nov 7, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 24, so the watching starts about Oct 8 — about 216 days after the spring freeze cleared.
How long is the growing season in Glenwood?
Measured between 28°F hard freezes, Glenwood sees about 216 frost-free days — roughly Apr 5 through Nov 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 26 to Oct 24, about 181 days.
Is the soil safe to grow vegetables in Glenwood?
The federal record around Glenwood runs heavier than most — 2,903 documented sites, mostly Underground Storage Tanks entries (1,456), the nearest PFAS record about 0.2 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.
How do I protect my plants from frost in Glenwood?
From about Oct 8 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 7 (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 7. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Glenwood's scale — its 6a band and its 216-day season. Your yard writes its own version of Glenwood'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 Glenwood’s own scale
7 of the readings below were taken at Glenwood's own scale — its own ~216-day season between 28°F freezes, the 2,102 acres it covers and 2,903 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Glenwood's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Glenwood's own 28°F hard-freeze dates, about Apr 5 and Nov 7 and the ~216-day span between themNOAA 1991–2020 Climate Normals
- 2,903 documented contamination sites on the federal record near Glenwood, the closest PFAS record about 0.2 miles out from the town centreFederal environmental registers
- Glenwood's boundary and the 2,102 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~216-day seasonGrowable Ground crop-matching engine
- The ecoregion at Glenwood's own centroid, the Central Corn Belt PlainsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Glenwoodlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Glenwood's 2,102 acres read through its county's SSURGO summaryfrom Cook County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Cook 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 Cook County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Glenwood's 2,102 acreswhy one lot differs from the next →
- Which side of Glenwood you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,102 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest PFAS 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 Glenwood-wide figureread your own land →