Ophiem, Illinois, sits in USDA hardiness zone 5b — a zone band wide enough that plant choice, not possibility, is the interesting question.
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 Ophiem, 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 Ophiem 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 Ophiem — soil, climate, flood, and parcel records. How we handle your address.
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Ophiem — the short answer
Ophiem, Illinois: USDA zone 5b, about 203 days between hard freezes, across 756 acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 8
- 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
- ~203
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 756 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 Ophiem's average, not your lot's — a low corner or a tree line moves it. Against Ophiem's 203-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Ophiem
Each reading below is measured for Ophiem itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredOphiem runs about 203 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
MeasuredOphiem 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 Ophiem is in
Ophiem sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Ophiem's own centroid rather than borrowed from Henry County.
What Grows in Ophiem
Every plant below cleared Ophiem's own zone 5b and its 203-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Ophiem?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 11; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 8 (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. 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 Ophiem
Closest first, within ~10 miles of Ophiem. Listing isn't leaking, and distance isn't exposure.
- NELSON FAMILY FARMSCAFO · 1.7 mi
- CURRY FARMSCAFO · 3.1 mi
- LYNN CENTER EQUIPMENT INCBrownfields · 3.1 mi
- National By-Products, Inc.Underground Storage Tanks · 3.2 mi
- IDOT Lynn Center Maint YardUnderground Storage Tanks · 3.5 mi
- Alpha DivUnderground Storage Tanks · 3.6 mi
- Drs Rehn & Larson PcUnderground Storage Tanks · 3.6 mi
- Growmark Inc Fs Dist CtrUnderground Storage Tanks · 3.6 mi
- Bills Auto RepairUnderground Storage Tanks · 3.6 mi
- L AND K ANDERSON FARMCAFO · 3.6 mi
- Richland Grove TownshipUnderground Storage Tanks · 3.7 mi
- SG SWINE - NEW WINDSORCAFO · 3.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Ophiem'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 Ophiem.
Total Sites
89
within ~10 miles of Ophiem
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Ophiem
Severity Distribution
within ~10 miles of Ophiem
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Ophiem, two things run higher than the national average within ~10 miles of Ophiem — CAFO (12 sites) and Underground Storage Tanks (61 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 Ophiem
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 Ophiem average
Your land is one point inside Ophiem
Everything above resolves to Ophiem as a whole — one PHZM band and one 28°F frost record, read across 756 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 Ophiem Average
Ophiem Average
- ●USDA Zones 5b, averaged across Ophiem
- ●One soil character for all of Ophiem
- ●Frost dates read at Ophiem's scale: Apr 8 to Oct 28
YOUR Parcel
- ✓Your exact zone, not Ophiem's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Ophiem
Pull a site-specific report for your exact address in Ophiem, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Ophiem averages can't show:
We read public map data around Ophiem — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Ophiem average
How we know this about Ophiem
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 Ophiem’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 Ophiem
When does frost risk typically end in Ophiem?
The last hard freeze (28°F) in Ophiem typically lands around Apr 8, 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 29.
When is the first frost in Ophiem?
The first hard freeze (28°F) in Ophiem 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 203 days after the spring freeze cleared.
How long is the growing season in Ophiem?
Measured between 28°F hard freezes, Ophiem sees about 203 frost-free days — roughly Apr 8 through Oct 28, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 29 to Oct 14, about 168 days.
Is the soil safe to grow vegetables in Ophiem?
The federal record around Ophiem shows 89 documented sites, mostly Underground Storage Tanks entries (61), the nearest CAFO record about 1.7 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Ophiem?
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 Ophiem's scale — its 5b band and its 203-day season. Your yard writes its own version of Ophiem'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 Ophiem’s own scale
6 of the readings below were taken at Ophiem's own scale — its own ~203-day season between 28°F freezes, the 756 acres it covers and 89 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Ophiem's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Ophiem's own 28°F hard-freeze dates, about Apr 8 and Oct 28 and the ~203-day span between themNOAA 1991–2020 Climate Normals
- 89 documented contamination sites on the federal record near Ophiem, the closest CAFO record about 1.7 miles out from the town centreFederal environmental registers
- Ophiem's boundary and the 756 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~203-day seasonGrowable Ground crop-matching engine
- The ecoregion at Ophiem'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 Ophiem's 756 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 Ophiem's 756 acreswhy one lot differs from the next →
- Which side of Ophiem you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 756 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest CAFO record about 1.7 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 Ophiem-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisOphiem sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides