Savanna, Illinois, sits in USDA hardiness zone 5a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Expect cabbage, cranberry, lavender, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Savanna, 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 Savanna 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 Savanna — soil, climate, flood, and parcel records. How we handle your address.
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Savanna — the short answer
Savanna, Illinois: USDA zone 5a, about 197 days between hard freezes, across 2K acres of city.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 9
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~197
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 2K 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 5a is Savanna's average, not your lot's — a low corner or a tree line moves it. Against Savanna's 197-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Savanna
Each reading below is measured for Savanna itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSavanna runs about 197 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredSavanna sits in USDA hardiness zone 5a.
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 Savanna is in
Savanna sits in the Driftless Area — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Savanna's own centroid, and it is not what its county reads: Carroll County is mostly Central Corn Belt Plains. The wider page above you is answering a different question about different ground.
What Grows in Savanna
Every plant below cleared Savanna's own zone 5a and its 197-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Savanna?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 23 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What's on the federal record near Savanna
Closest first, within ~10 miles of Savanna. Listing isn't leaking, and distance isn't exposure.
- Savanna StationUnderground Storage Tanks · 1900 ft
- Big 10 MartUnderground Storage Tanks · 2000 ft
- Casey's General Store #2535Underground Storage Tanks · 2200 ft
- Econo Gas StationUnderground Storage Tanks · 2300 ft
- Mt Carroll Microwave SiteUnderground Storage Tanks · 0.6 mi
- Soo Line RrUnderground Storage Tanks · 0.6 mi
- Burlington NorthernUnderground Storage Tanks · 0.6 mi
- Michl Oil CoUnderground Storage Tanks · 0.8 mi
- Lazy River Marina IncUnderground Storage Tanks · 0.8 mi
- J & L Oil IncUnderground Storage Tanks · 0.8 mi
- Savanna MarinaUnderground Storage Tanks · 0.8 mi
- UNITED STATES POST OFFICEBrownfields · 0.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Savanna'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 Savanna.
Total Sites
100
within ~10 miles of Savanna
Risk Level
Moderate
Highest-severity
8 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Savanna
Severity Distribution
within ~10 miles of Savanna
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Savanna, two things run higher than the national average within ~10 miles of Savanna — CAFO (3 sites) and Toxics Release Inventory (8 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.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Savanna
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 Savanna average
Your land is one point inside Savanna
Everything above resolves to Savanna as a whole — one PHZM band and one 28°F frost record, read across 2K 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 Savanna Average
Savanna Average
- ●USDA Zones 5a, averaged across Savanna
- ●One soil character for all of Savanna
- ●Frost dates read at Savanna's scale: Apr 9 to Oct 23
YOUR Parcel
- ✓Your exact zone, not Savanna's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Savanna
Pull a site-specific report for your exact address in Savanna, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Savanna averages can't show:
We read public map data around Savanna — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Savanna average
How we know this about Savanna
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 Savanna’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 Savanna
When does frost risk typically end in Savanna?
The last hard freeze (28°F) in Savanna typically lands around Apr 9, 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 30.
When is the first frost in Savanna?
The first hard freeze (28°F) in Savanna typically arrives around Oct 23, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 9, so the watching starts about Sep 23 — about 197 days after the spring freeze cleared.
How long is the growing season in Savanna?
Measured between 28°F hard freezes, Savanna sees about 197 frost-free days — roughly Apr 9 through Oct 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 30 to Oct 9, about 162 days.
Is the soil safe to grow vegetables in Savanna?
The federal record around Savanna shows 100 documented sites, mostly Underground Storage Tanks entries (60), the nearest Underground Storage Tanks record about 0.4 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 Savanna?
From about Sep 23 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 23 (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 23. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Savanna's scale — its 5a band and its 197-day season. Your yard writes its own version of Savanna'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 Savanna’s own scale
6 of the readings below were taken at Savanna's own scale — its own ~197-day season between 28°F freezes, the 1,674 acres it covers and 100 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Savanna's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Savanna's own 28°F hard-freeze dates, about Apr 9 and Oct 23 and the ~197-day span between themNOAA 1991–2020 Climate Normals
- 100 documented contamination sites on the federal record near Savanna, the closest Underground Storage Tanks record about 0.4 miles out from the town centreFederal environmental registers
- Savanna's boundary and the 1,674 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~197-day seasonGrowable Ground crop-matching engine
- Savanna sits in the Driftless Area — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Savanna's 1,674 acres read through its county's SSURGO summaryfrom Carroll County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Carroll 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 Carroll County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Savanna's 1,674 acreswhy one lot differs from the next →
- Which side of Savanna you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,674 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.4 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 Savanna-wide figureread your own land →
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