Delavan, Illinois, sits in USDA hardiness zone 6a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
On paper, cabbage, hazelnut, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Delavan, 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 Delavan 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 Delavan — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Delavan — the short answer
Delavan, Illinois: USDA zone 6a, about 207 days between hard freezes, across 923 acres of city.
- 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)
- Oct 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~207
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 923 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 Delavan's average, not your lot's — a low corner or a tree line moves it. Against Delavan's 207-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Delavan
Each reading below is measured for Delavan itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDelavan runs about 207 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
MeasuredDelavan 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 Delavan is in
Delavan sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Delavan's own centroid rather than borrowed from Tazewell County.
What Grows in Delavan
Every plant below cleared Delavan's own zone 6a and its 207-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Delavan?
Usually not — gardeners here simply switch what goes in the ground as the season moves. 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 Oct 29 — 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's on the federal record near Delavan
Closest first, within ~10 miles of Delavan. Listing isn't leaking, and distance isn't exposure.
- DOLLAR GENERAL STORE 8435Brownfields · 150 ft
- Dicks Super SerUnderground Storage Tanks · 300 ft
- Noonan True Value HardwareUnderground Storage Tanks · 300 ft
- DICKS SUPER SVCBrownfields · 350 ft
- Ag-Land Fs IncUnderground Storage Tanks · 500 ft
- Marco Farm SupplyUnderground Storage Tanks · 550 ft
- Delavan RadioUnderground Storage Tanks · 550 ft
- Bhalla Oil CompanyUnderground Storage Tanks · 550 ft
- Delavan Cooperative Elevator CoUnderground Storage Tanks · 600 ft
- Burrell CharlesUnderground Storage Tanks · 900 ft
- Delavan Twp GarageUnderground Storage Tanks · 1600 ft
- Casey's General Store #2649Underground Storage Tanks · 1700 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Delavan'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 Delavan.
Total Sites
76
within ~10 miles of Delavan
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Delavan
Severity Distribution
within ~10 miles of Delavan
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Delavan, CAFO runs higher than the national average — 10 sites within ~10 miles of Delavan. 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.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Check your specific parcel in Delavan
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 Delavan average
Your land is one point inside Delavan
Everything above resolves to Delavan as a whole — one PHZM band and one 28°F frost record, read across 923 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 city 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 Delavan Average
Delavan Average
- ●USDA Zones 6a, averaged across Delavan
- ●One soil character for all of Delavan
- ●Frost dates read at Delavan's scale: Apr 5 to Oct 29
YOUR Parcel
- ✓Your exact zone, not Delavan's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Delavan
Pull a site-specific report for your exact address in Delavan, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Delavan averages can't show:
We read public map data around Delavan — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Delavan average
How we know this about Delavan
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Delavan’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 city grain anywhere on this page — there is no city-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 Delavan
When does frost risk typically end in Delavan?
The last hard freeze (28°F) in Delavan 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 Delavan?
The first hard freeze (28°F) in Delavan typically arrives around Oct 29, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 15, so the watching starts about Sep 29 — about 207 days after the spring freeze cleared.
How long is the growing season in Delavan?
Measured between 28°F hard freezes, Delavan sees about 207 frost-free days — roughly Apr 5 through Oct 29, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 26 to Oct 15, about 172 days.
Is the soil safe to grow vegetables in Delavan?
The federal record around Delavan is a meaningful one — 76 documented sites, mostly Underground Storage Tanks entries (41), the nearest Brownfields record under a tenth of a mile 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 Delavan?
From about Sep 29 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 29 (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 29. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Delavan's scale — its 6a band and its 207-day season. Your yard writes its own version of Delavan'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 Delavan’s own scale
6 of the readings below were taken at Delavan's own scale — its own ~207-day season between 28°F freezes, the 923 acres it covers and 76 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Delavan's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Delavan's own 28°F hard-freeze dates, about Apr 5 and Oct 29 and the ~207-day span between themNOAA 1991–2020 Climate Normals
- 76 documented contamination sites on the federal record near Delavan, the closest Brownfields record under a tenth of a mile out from the town centreFederal environmental registers
- Delavan's boundary and the 923 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~207-day seasonGrowable Ground crop-matching engine
- The ecoregion at Delavan'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 Delavan's 923 acres read through its county's SSURGO summaryfrom Tazewell County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Tazewell 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 Tazewell County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Delavan's 923 acreswhy one lot differs from the next →
- Which side of Delavan you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 923 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record under a tenth of a mile 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 Delavan-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisDelavan sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides