Williamsfield, Illinois, sits in USDA hardiness zone 5b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
A short list that earns its place here — cabbage, cranberry, lavender, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in Williamsfield, 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 Williamsfield 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 Williamsfield — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Williamsfield — the short answer
Williamsfield, Illinois: USDA zone 5b, about 201 days between hard freezes, across 788 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 28
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~201
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 788 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 Williamsfield's average, not your lot's — a low corner or a tree line moves it. Against Williamsfield's 201-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Williamsfield
Each reading below is measured for Williamsfield itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredWilliamsfield runs about 201 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
MeasuredWilliamsfield 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 Williamsfield is in
Williamsfield sits in the Interior River Valleys and Hills — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Williamsfield's own centroid rather than borrowed from Knox County.
What Grows in Williamsfield
Every plant below cleared Williamsfield's own zone 5b and its 201-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Williamsfield?
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 28 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
What's on the federal record near Williamsfield
Closest first, within ~10 miles of Williamsfield. Listing isn't leaking, and distance isn't exposure.
- Williamsfield Comm Unit Dist 210Underground Storage Tanks · 700 ft
- Truro Township OfUnderground Storage Tanks · 950 ft
- Municipal GarageUnderground Storage Tanks · 1100 ft
- Williamsfield Retirement CenterUnderground Storage Tanks · 1100 ft
- Former Tucker FacilityUnderground Storage Tanks · 1200 ft
- Hurlbutt, Clayton T.Underground Storage Tanks · 1200 ft
- Lynn SunocoUnderground Storage Tanks · 1300 ft
- Williamsfield Fast StopUnderground Storage Tanks · 1300 ft
- Galifield IncUnderground Storage Tanks · 1600 ft
- Former Traveler's MartUnderground Storage Tanks · 1900 ft
- I M CUnderground Storage Tanks · 2600 ft
- Wight Chevrolet CoUnderground Storage Tanks · 0.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Williamsfield'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 Williamsfield.
Total Sites
45
within ~10 miles of Williamsfield
Risk Level
Low
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Williamsfield
Severity Distribution
within ~10 miles of Williamsfield
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Williamsfield, two things run higher than the national average within ~10 miles of Williamsfield — CAFO (3 sites) and Underground Storage Tanks (36 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Williamsfield
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 Williamsfield average
Your land is one point inside Williamsfield
Everything above resolves to Williamsfield as a whole — one PHZM band and one 28°F frost record, read across 788 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 Williamsfield Average
Williamsfield Average
- ●USDA Zones 5b, averaged across Williamsfield
- ●One soil character for all of Williamsfield
- ●Frost dates read at Williamsfield's scale: Apr 10 to Oct 28
YOUR Parcel
- ✓Your exact zone, not Williamsfield's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Williamsfield
Pull a site-specific report for your exact address in Williamsfield, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Williamsfield averages can't show:
We read public map data around Williamsfield — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Williamsfield average
How we know this about Williamsfield
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 Williamsfield’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 Williamsfield
When does frost risk typically end in Williamsfield?
The last hard freeze (28°F) in Williamsfield 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 Williamsfield?
The first hard freeze (28°F) in Williamsfield typically arrives around Oct 28, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 14, so the watching starts about Sep 28 — about 201 days after the spring freeze cleared.
How long is the growing season in Williamsfield?
Measured between 28°F hard freezes, Williamsfield sees about 201 frost-free days — roughly Apr 10 through Oct 28, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 1 to Oct 14, about 166 days.
Is the soil safe to grow vegetables in Williamsfield?
The federal record around Williamsfield is light — 45 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (36), the nearest Underground Storage Tanks record about 0.1 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Williamsfield?
From about Sep 28 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 28 (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 28. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Williamsfield's scale — its 5b band and its 201-day season. Your yard writes its own version of Williamsfield'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 Williamsfield’s own scale
6 of the readings below were taken at Williamsfield's own scale — its own ~201-day season between 28°F freezes, the 788 acres it covers and 45 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Williamsfield's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Williamsfield's own 28°F hard-freeze dates, about Apr 10 and Oct 28 and the ~201-day span between themNOAA 1991–2020 Climate Normals
- 45 documented contamination sites on the federal record near Williamsfield, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Williamsfield's boundary and the 788 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~201-day seasonGrowable Ground crop-matching engine
- The ecoregion at Williamsfield's own centroid, the Interior River Valleys and HillsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Williamsfield's 788 acres read through its county's SSURGO summaryfrom Knox County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Knox 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 Knox County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Williamsfield's 788 acreswhy one lot differs from the next →
- Which side of Williamsfield you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 788 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Williamsfield-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisWilliamsfield sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides