Mill Creek, Illinois, sits in USDA hardiness zone 7a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Crops well matched to these conditions include cabbage, hazelnut, california poppy, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Mill Creek, 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 Mill Creek 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 Mill Creek — soil, climate, flood, and parcel records. How we handle your address.
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Mill Creek — the short answer
Mill Creek, Illinois: USDA zone 7a, about 241 days between hard freezes, across 241 acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 16
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~241
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 241 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 7a is Mill Creek's average, not your lot's — a low corner or a tree line moves it. Against Mill Creek's 241-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Mill Creek
Each reading below is measured for Mill Creek itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMill Creek runs about 241 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
MeasuredMill Creek sits in USDA hardiness zone 7a.
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 Mill Creek is in
Mill Creek sits in the Interior Plateau — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Mill Creek's own centroid rather than borrowed from Union County.
What Grows in Mill Creek
Every plant below cleared Mill Creek's own zone 7a and its 241-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Mill Creek?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Feb 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 20 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 16 — 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 Mill Creek
Closest first, within ~10 miles of Mill Creek. Listing isn't leaking, and distance isn't exposure.
- ANNA QUARRIES INCBrownfields · 2.2 mi
- Jonesboro Health Care CenterUnderground Storage Tanks · 4.8 mi
- Dongola Village Garage BldgUnderground Storage Tanks · 4.8 mi
- Dongola Unit School Dist #66Underground Storage Tanks · 4.9 mi
- Corzine ServiceUnderground Storage Tanks · 5.1 mi
- DOLLAR GENERAL STORE 13825Brownfields · 5.1 mi
- Jerrys Service StationUnderground Storage Tanks · 5.2 mi
- Ullin Auto Body WorksUnderground Storage Tanks · 5.4 mi
- Cheek Oil CoUnderground Storage Tanks · 5.4 mi
- Southern Il Electric CoopUnderground Storage Tanks · 5.4 mi
- AceesUnderground Storage Tanks · 5.6 mi
- Fruit Belt Ser CoUnderground Storage Tanks · 5.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Mill Creek'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 Mill Creek.
Total Sites
112
within ~10 miles of Mill Creek
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Mill Creek
Severity Distribution
within ~10 miles of Mill Creek
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mill Creek, Underground Storage Tanks runs higher than the national average — 82 sites within ~10 miles of Mill Creek. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Mill Creek
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 Mill Creek average
Your land is one point inside Mill Creek
Everything above resolves to Mill Creek as a whole — one PHZM band and one 28°F frost record, read across 241 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 Mill Creek Average
Mill Creek Average
- ●USDA Zones 7a, averaged across Mill Creek
- ●One soil character for all of Mill Creek
- ●Frost dates read at Mill Creek's scale: Mar 20 to Nov 16
YOUR Parcel
- ✓Your exact zone, not Mill Creek's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Mill Creek
Pull a site-specific report for your exact address in Mill Creek, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mill Creek averages can't show:
We read public map data around Mill Creek — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mill Creek average
How we know this about Mill Creek
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 Mill Creek’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 Mill Creek
When does frost risk typically end in Mill Creek?
The last hard freeze (28°F) in Mill Creek typically lands around Mar 20, 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 10.
When is the first frost in Mill Creek?
The first hard freeze (28°F) in Mill Creek typically arrives around Nov 16, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 2, so the watching starts about Oct 17 — about 241 days after the spring freeze cleared.
How long is the growing season in Mill Creek?
Measured between 28°F hard freezes, Mill Creek sees about 241 frost-free days — roughly Mar 20 through Nov 16, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 10 to Nov 2, about 206 days.
Is the soil safe to grow vegetables in Mill Creek?
The federal record around Mill Creek shows 112 documented sites, mostly Underground Storage Tanks entries (82), the nearest Brownfields record about 2.2 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 Mill Creek?
From about Oct 17 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 16 (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 16. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Mill Creek's scale — its 7a band and its 241-day season. Your yard writes its own version of Mill Creek'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 Mill Creek’s own scale
6 of the readings below were taken at Mill Creek's own scale — its own ~241-day season between 28°F freezes, the 241 acres it covers and 112 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Mill Creek's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Mill Creek's own 28°F hard-freeze dates, about Mar 20 and Nov 16 and the ~241-day span between themNOAA 1991–2020 Climate Normals
- 112 documented contamination sites on the federal record near Mill Creek, the closest Brownfields record about 2.2 miles out from the town centreFederal environmental registers
- Mill Creek's boundary and the 241 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~241-day seasonGrowable Ground crop-matching engine
- The ecoregion at Mill Creek's own centroid, the Interior PlateauUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Mill Creek's 241 acres read through its county's SSURGO summaryfrom Union County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Union 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 Union County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Mill Creek's 241 acreswhy one lot differs from the next →
- Which side of Mill Creek you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 241 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 2.2 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 Mill Creek-wide figureread your own land →