Dover, Illinois, sits in USDA hardiness zone 5b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Reliable performers under these conditions include cabbage, cranberry, lavender, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Dover, 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 Dover 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 Dover — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Dover — the short answer
Dover, Illinois: USDA zone 5b, about 201 days between hard freezes, across 174 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
- 174 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 Dover's average, not your lot's — a low corner or a tree line moves it. Against Dover's 201-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Dover
Each reading below is measured for Dover itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDover 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
MeasuredDover 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 Dover is in
Dover sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Dover's own centroid rather than borrowed from Bureau County.
What Grows in Dover
Every plant below cleared Dover'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 Dover?
Usually not — gardeners here simply switch what goes in the ground as the season moves. 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 Dover
Closest first, within ~10 miles of Dover. Listing isn't leaking, and distance isn't exposure.
- DOVERPFAS · 450 ft
- Aj Country Car CornerUnderground Storage Tanks · 950 ft
- Dover Gas & GroceryUnderground Storage Tanks · 1100 ft
- Prairie View HomeUnderground Storage Tanks · 0.8 mi
- Lutes Well Drilling IncUnderground Storage Tanks · 1.5 mi
- Malden Grade SchoolUnderground Storage Tanks · 1.5 mi
- 17N10E-29.5c2Nitrate · 1.6 mi
- Malden Repair BldgUnderground Storage Tanks · 1.6 mi
- Berlin Township OfUnderground Storage Tanks · 1.8 mi
- AG VIEW FSBrownfields · 2.3 mi
- PENSKE TRUCK LEASING CO LPBrownfields · 3.6 mi
- HOLLANDS WEST INCBrownfields · 3.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Dover'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 Dover.
Sources Checked
within ~10 miles of Dover
Severity Distribution
within ~10 miles of Dover
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Dover, two things run higher than the national average within ~10 miles of Dover — Superfund (3 sites) and Underground Storage Tanks (103 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Dover
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 Dover average
Your land is one point inside Dover
Everything above resolves to Dover as a whole — one PHZM band and one 28°F frost record, read across 174 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 Dover Average
Dover Average
- ●USDA Zones 5b, averaged across Dover
- ●One soil character for all of Dover
- ●Frost dates read at Dover's scale: Apr 10 to Oct 28
YOUR Parcel
- ✓Your exact zone, not Dover's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Dover
Pull a site-specific report for your exact address in Dover, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Dover averages can't show:
We read public map data around Dover — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Dover average
How we know this about Dover
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 Dover’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 Dover
When does frost risk typically end in Dover?
The last hard freeze (28°F) in Dover 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 Dover?
The first hard freeze (28°F) in Dover 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 Dover?
Measured between 28°F hard freezes, Dover 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 Dover?
The federal record around Dover is a meaningful one — 152 documented sites, mostly Underground Storage Tanks entries (103), the nearest PFAS record under a tenth of a mile out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do I protect my plants from frost in Dover?
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 Dover's scale — its 5b band and its 201-day season. Your yard writes its own version of Dover'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 Dover’s own scale
6 of the readings below were taken at Dover's own scale — its own ~201-day season between 28°F freezes, the 174 acres it covers and 152 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Dover's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Dover's own 28°F hard-freeze dates, about Apr 10 and Oct 28 and the ~201-day span between themNOAA 1991–2020 Climate Normals
- 152 documented contamination sites on the federal record near Dover, the closest PFAS record under a tenth of a mile out from the town centreFederal environmental registers
- Dover's boundary and the 174 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 Dover'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 Dover's 174 acres read through its county's SSURGO summaryfrom Bureau County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Bureau 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 Bureau County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Dover's 174 acreswhy one lot differs from the next →
- Which side of Dover you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 174 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest PFAS record under a tenth of a mile 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 Dover-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisDover sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides