St. Peter, Illinois, sits in USDA hardiness zone 6b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Growers here do well with cabbage, hazelnut, lavender, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in St. Peter, 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 St. Peter 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 St. Peter — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
St. Peter — the short answer
St. Peter, Illinois: USDA zone 6b, about 217 days between hard freezes, across 333 acres of town.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~217
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 333 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 6b is St. Peter's average, not your lot's — a low corner or a tree line moves it. Against St. Peter's 217-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in St. Peter
Each reading below is measured for St. Peter itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSt. Peter runs about 217 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
MeasuredSt. Peter sits in USDA hardiness zone 6b.
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 St. Peter is in
St. Peter sits in the Interior River Valleys and Hills — EPA Level III, inside the wider Eastern Temperate Forests. That is read at St. Peter's own centroid rather than borrowed from Fayette County.
What Grows in St. Peter
Every plant below cleared St. Peter's own zone 6b and its 217-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in St. Peter?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 2; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 30 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 2 — 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 St. Peter
Closest first, within ~10 miles of St. Peter. Listing isn't leaking, and distance isn't exposure.
- W A Borchelt Lumber CoUnderground Storage Tanks · 800 ft
- Dougs & Toms StationUnderground Storage Tanks · 1100 ft
- South Central FS, Inc.Underground Storage Tanks · 1100 ft
- St Peter LumberUnderground Storage Tanks · 1100 ft
- Q Farms FertilizerUnderground Storage Tanks · 1300 ft
- E J WATER COOPPFAS · 1.9 mi
- St James ToolhouseUnderground Storage Tanks · 1.9 mi
- St. Peter Auto BodyUnderground Storage Tanks · 1.9 mi
- Wabash Independent Oil CoUnderground Storage Tanks · 3.5 mi
- Green/Line Equip IncUnderground Storage Tanks · 4.0 mi
- Jack Flash - FarinaUnderground Storage Tanks · 4.2 mi
- DOLLAR GENERAL STORE 11707Brownfields · 4.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from St. Peter'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 St. Peter.
Total Sites
33
within ~10 miles of St. Peter
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of St. Peter
Severity Distribution
within ~10 miles of St. Peter
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around St. Peter, Underground Storage Tanks runs higher than the national average — 24 sites within ~10 miles of St. Peter. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
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 St. Peter
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 St. Peter average
Your land is one point inside St. Peter
Everything above resolves to St. Peter as a whole — one PHZM band and one 28°F frost record, read across 333 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 St. Peter Average
St. Peter Average
- ●USDA Zones 6b, averaged across St. Peter
- ●One soil character for all of St. Peter
- ●Frost dates read at St. Peter's scale: Mar 30 to Nov 2
YOUR Parcel
- ✓Your exact zone, not St. Peter's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in St. Peter
Pull a site-specific report for your exact address in St. Peter, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that St. Peter averages can't show:
We read public map data around St. Peter — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the St. Peter average
How we know this about St. Peter
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 St. Peter’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 St. Peter
When does frost risk typically end in St. Peter?
The last hard freeze (28°F) in St. Peter typically lands around Mar 30, 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 20.
When is the first frost in St. Peter?
The first hard freeze (28°F) in St. Peter typically arrives around Nov 2, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 19, so the watching starts about Oct 3 — about 217 days after the spring freeze cleared.
How long is the growing season in St. Peter?
Measured between 28°F hard freezes, St. Peter sees about 217 frost-free days — roughly Mar 30 through Nov 2, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 20 to Oct 19, about 182 days.
Is the soil safe to grow vegetables in St. Peter?
The federal record around St. Peter shows 33 documented sites, mostly Underground Storage Tanks entries (24), the nearest Underground Storage Tanks record about 0.2 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 St. Peter?
From about Oct 3 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 2 (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 2. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at St. Peter's scale — its 6b band and its 217-day season. Your yard writes its own version of St. Peter'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 St. Peter’s own scale
6 of the readings below were taken at St. Peter's own scale — its own ~217-day season between 28°F freezes, the 333 acres it covers and 33 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- St. Peter's own USDA hardiness band, zones 6bUSDA PHZM 2023
- St. Peter's own 28°F hard-freeze dates, about Mar 30 and Nov 2 and the ~217-day span between themNOAA 1991–2020 Climate Normals
- 33 documented contamination sites on the federal record near St. Peter, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- St. Peter's boundary and the 333 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~217-day seasonGrowable Ground crop-matching engine
- The ecoregion at St. Peter'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 St. Peter's 333 acres read through its county's SSURGO summaryfrom Fayette County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Fayette 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 Fayette County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among St. Peter's 333 acreswhy one lot differs from the next →
- Which side of St. Peter you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 333 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 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 St. Peter-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisSt. Peter sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides