Annawan, Illinois, sits in USDA hardiness zone 5b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Crops well matched to these conditions include cabbage, cranberry, lavender, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Annawan, 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 Annawan 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 Annawan — soil, climate, flood, and parcel records. How we handle your address.
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Annawan — the short answer
Annawan, Illinois: USDA zone 5b, about 200 days between hard freezes, across 1K acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 27
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~200
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 Annawan's average, not your lot's — a low corner or a tree line moves it. Against Annawan's 200-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Annawan
Each reading below is measured for Annawan itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredAnnawan runs about 200 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
MeasuredAnnawan 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 Annawan is in
Annawan sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Annawan's own centroid rather than borrowed from Henry County.
What Grows in Annawan
Every plant below cleared Annawan's own zone 5b and its 200-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Annawan?
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 13; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 10 (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. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
What's on the federal record near Annawan
Closest first, within ~10 miles of Annawan. Listing isn't leaking, and distance isn't exposure.
- Annawan Fuel 24Underground Storage Tanks · 0.7 mi
- Tomahawk StationUnderground Storage Tanks · 0.8 mi
- JACKSON COLLISION REPAIRBrownfields · 0.8 mi
- Jaswal, Inc.Underground Storage Tanks · 0.8 mi
- Express Lane #69Underground Storage Tanks · 0.8 mi
- Tazewell Builder Supply IncUnderground Storage Tanks · 0.9 mi
- CHS ANNAWAN - TEST WELL CONSTRUCTIONToxics Release Inventory · 1.0 mi
- CHS ANNAWAN - TEST WELL CONSTRUCTIONBrownfields · 1.0 mi
- Thompson FarmUnderground Storage Tanks · 1.0 mi
- Annawan Unit Dist 226Underground Storage Tanks · 1.0 mi
- 2.5 miles NE of AnnawanNitrate · 1.3 mi
- Far Mar Chonstruction CoUnderground Storage Tanks · 3.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Annawan'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 Annawan.
Total Sites
78
within ~10 miles of Annawan
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Annawan
Severity Distribution
within ~10 miles of Annawan
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Annawan, two things run higher than the national average within ~10 miles of Annawan — CAFO (7 sites) and Underground Storage Tanks (48 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.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Annawan
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 Annawan average
Your land is one point inside Annawan
Everything above resolves to Annawan as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Annawan Average
Annawan Average
- ●USDA Zones 5b, averaged across Annawan
- ●One soil character for all of Annawan
- ●Frost dates read at Annawan's scale: Apr 10 to Oct 27
YOUR Parcel
- ✓Your exact zone, not Annawan's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Annawan
Pull a site-specific report for your exact address in Annawan, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Annawan averages can't show:
We read public map data around Annawan — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Annawan average
How we know this about Annawan
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 Annawan’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 Annawan
When does frost risk typically end in Annawan?
The last hard freeze (28°F) in Annawan typically lands around Apr 10, 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 May 1.
When is the first frost in Annawan?
The first hard freeze (28°F) in Annawan typically arrives around Oct 27, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 13, so the watching starts about Sep 27 — about 200 days after the spring freeze cleared.
How long is the growing season in Annawan?
Measured between 28°F hard freezes, Annawan sees about 200 frost-free days — roughly Apr 10 through Oct 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 1 to Oct 13, about 165 days.
Is the soil safe to grow vegetables in Annawan?
The federal record around Annawan is a meaningful one — 78 documented sites, mostly Underground Storage Tanks entries (48), the nearest Underground Storage Tanks record about 0.7 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 Annawan?
From about Sep 27 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 27 (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 27. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Annawan's scale — its 5b band and its 200-day season. Your yard writes its own version of Annawan'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 Annawan’s own scale
6 of the readings below were taken at Annawan's own scale — its own ~200-day season between 28°F freezes, the 1,371 acres it covers and 78 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Annawan's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Annawan's own 28°F hard-freeze dates, about Apr 10 and Oct 27 and the ~200-day span between themNOAA 1991–2020 Climate Normals
- 78 documented contamination sites on the federal record near Annawan, the closest Underground Storage Tanks record about 0.7 miles out from the town centreFederal environmental registers
- Annawan's boundary and the 1,371 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~200-day seasonGrowable Ground crop-matching engine
- The ecoregion at Annawan'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 Annawan's 1,371 acres read through its county's SSURGO summaryfrom Henry County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Henry 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 Henry County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Annawan's 1,371 acreswhy one lot differs from the next →
- Which side of Annawan you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,371 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.7 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 Annawan-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisAnnawan sits outside our named growing regions, so Illinois as a whole is its closest context here.